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pdfEconomic
Research
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Economic
Research
Report
Number 290
June 2021
Honey Bees on the Move:
From Pollination to Honey
Production and Back
Jennifer K. Bond, Claudia Hitaj, David Smith, Kevin
Hunt, Agnes Perez, and Gustavo Ferreira
Economic Research Service
www.ers.usda.gov
Recommended citation format for this publication:
Bond, Jennifer K., Claudia Hitaj, David Smith, Kevin Hunt, Agnes Perez, and Gustavo Ferreira.
June 2021. Honey Bees on the Move: From Pollination to Honey Production and Back,
ERR-290, U.S. Department of Agriculture, Economic Research Service.
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Economic
Research
Service
Economic
Research
Report
Number 290
June 2021
Honey Bees on the Move:
From Pollination to Honey Production
and Back
Jennifer K. Bond, Claudia Hitaj, David Smith, Kevin Hunt,
Agnes Perez, and Gustavo Ferreira
Abstract
Driven by growing consumer demand for fruits, nuts, and vegetables, U.S. growers are expanding their
cultivation of these pollinator-dependent crops. To service the rising number of pollination contracts
and seek out quality forage to produce honey, beekeepers move their bees around the country. Limited
nationwide data exist on the number of honey bee colonies that pass through each State throughout
the year, the routes these colonies take, and the distances traveled. Using data from a USDA survey
of beekeepers, this report quantifies honey bee colony movements over the four seasons and provides
a basis for understanding how the transport of honey bee colonies affects pollination services, honey
production, and the loss of colonies. The intensity of the use of pollination services across a variety of
pollinator-dependent crops in various regions and States is also summarized to explain the timing and
volume of colony movements.
mellifera Conservation
Keywords: honey bees, honey, pollination, pollinator, honey bee colonies, Apis mellifera,
Reserve Program, beekeepers, almonds, forage, U.S Department of Agriculture, USDA, Economic
Research Service, ERS
Acknowledgments: The authors thank Lindsay Drunasky of USDA’s National Agricultural Statistics
Service (NASS) for providing information on the Colony Loss Survey. The authors also thank Brittney
Goodrich from the University of California, Davis for providing us with summaries of apiary shipments
into California from the California Department of Food and Agriculture. Thanks also to Christopher
Whitney, Mary Ahearn, and Krishna Paudel of USDA, Economic Research Service (ERS) for editorial
assistance and Tiffany Lanigan, USDA, ERS, for design services.
About the Authors: Jennifer K. Bond is Deputy Director for Outlook and Staff Analysis at the USDA,
Economic Research Service ([email protected]); Claudia Hitaj is a Research and Technology
Associate at the Department of Environmental Research and Innovation at the Luxembourg Institute
of Science and Technology ([email protected]); David Smith is a former Economist at the USDA,
Economic Research Service ([email protected]); Kevin Hunt is a Geographer at the USDA,
National Agricultural Statistics Service ([email protected]); Agnes Perez is a former Agricultural
Economist at the USDA, Economic Research Service; and Gustavo Ferreira ([email protected])
is an Agricultural Marketing Specialist with the USDA, Agricultural Marketing Service.
Contents
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Honey Bees Provide Pollination Services for Geographically Diverse Crops . . . . . . . . . . . . . . . . .4
Crop Dependency for Commercial Honey Bees for Pollination Varies Greatly
by Crop and Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Honey Production Linked to Forage Resource Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Following Honey Bee Colonies Through the Seasons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Commercial Honey Bee Movements are Strongly Seasonal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Colony Health is Affected by Long-Distance Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
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USDA, Economic Research Service
A report summary from the Economic Research Service
June 2021
Honey Bees on the Move: From Pollination
to Honey Production and Back
Jennifer K. Bond, Claudia Hitaj, David Smith, Kevin Hunt, Agnes Perez, and
Gustavo Ferreira
Economic
Research
Service
What Is the Issue?
Economic
Research
Report
Number 290
June 2021
The production of many fruits, nuts, and vegetables depends on pollination
services provided by honey bees (Apis
Apis mellifera).
mellifera) In recent years, increased
demand for these crops has resulted in growing production and rising demand
for pollination services. To provide pollination services and produce honey, many
beekeepers transport their colonies (also called hives) around the country during
the year. Limited nationwide data exist on the number of honey bee colonies that
reside in or pass through each State throughout the year, the routes these colonies
take, and the distances colonies are transported.
Honey Bees on the Move:
From Pollination to Honey
Production and Back
Jennifer K. Bond, Claudia Hitaj, David Smith, Kevin
Hunt, Agnes Perez, and Gustavo Ferreira
Using data from USDA, National Agricultural Statistics Service’s survey of
beekeepers, this report describes connections between colony movements, pollinated crop production, and forage
availability. This study also quantifies honey bee colony movement patterns and distances, providing a basis to
understand how the transport of honey bee colonies influences the provision of pollination services, honey production, and colony loss. Estimates of the varying intensity of pollination service use across crops and regions are also
derived.
What Did the Study Find?
Honey bee colonies travel along seasonal routes across the United States. This travel is driven by the provision of
pollination services (valued at roughly $250 million to more than $320 million annually); the search for forage to
produce honey (valued at about $330 million annually); and the need to enhance colony survival and growth. These
movements highlight the link between the production of pollinated nuts, fruits, vegetables, and seeds—especially
in California—and access to the rich forage resources of the Northern Great Plains, including acreage enrolled in
the Conservation Reserve Program (CRP).
ERS is a primary source of economic research and analysis from the U.S. Department of Agriculture, providing
timely information on economic and policy issues related to agriculture, food, the environment, and rural America.
www.ers.usda.gov
• From winter (January 1, 2017) to summer (July 1, 2017), beekeepers transported about 30 percent of all U.S.
commercial honey bee colonies into the Northern Great Plains from other States. After summer and as the
weather turns colder, most hives are moved out of the Northern Great Plains and into warmer States in the
Southern United States, including California, to overwinter. During the survey period, about 5 percent of all
hives in the United States overwinter in the Northern Plains.
• From summer (July 1, 2017) to winter (January 1, 2018), the major flow of honey bees is into California
(figure 1). By far, the largest share of colonies that moved into California by January came from the Northern
Great Plains (63 percent). Two adjacent regions, the West and Pacific Northwest, are also important sources
of colonies for California at 11 and 10 percent. A further 6 percent of colonies came from the Northeast.
• The intensity of pollination services used varies widely by crop, across regions, and even within the same crop
family in different locations, helping to explain variations in seasonal colony transportation patterns.
• Almonds, the seventh most valuable crop in the United States at approximately $5.6 billion, represent the
largest pollination service market for honey bees. California almond producers alone accounted for 80
percent of payments for pollination services during 2017.
• Flowering grasslands in the Northern Great Plains, which includes Minnesota, Montana, North Dakota,
and South Dakota, feature a relatively high concentration of Conservation Reserve Program (CRP) acreage.
About 21 percent of the Nation’s CRP land is in the Northern Great Plains, and CRP land in this region is
highly suitable foraging ground for pollinators.
• Good forage resources are typically associated with higher volumes of honey production. Between spring and
summer, the number of honey bee colonies in the Northern Great Plains—which is especially valued for its
honey bee forage resources—more than quadruples. North Dakota alone typically accounts for nearly onefifth of the total value of U.S. honey production.
• The declining availability of forage land that is highly suitable for honey bees contributes to the increasing
cost of beekeeping. Rising beekeeping costs are at least partially passed on to pollination-dependent crop
producers via increased pollination service fees.
• Long-distance transportation of colonies for pollination services and honey production is associated with
increased colony stress and loss, as honey bees cannot forage during transport and may be subjected to excessive heat or cold, depending on the season. Transportation stress can be mitigated with enhanced management strategies.
www.ers.usda.gov
Figure 1
Honey bee colony movements into California, July 1, 2017-January 1, 2018
Pacific Northwest
Northern Great Plains
West
Northeast
Number of
colonies
Midwest
384,600
California
65,600
62,900
38,500
Southeast
South
29,900
D
D
Notes: D—Estimate is not shown to avoid disclosing data for individual operations. The width of the arrows is proportional to the number of colonies
moved; line curvature is indicative of non-linear route paths. Hawaii and Alaska are excluded from this route map as local colonies are not indicated
to travel to or from these States to other regions in the continental United States. Orange colored areas represent the predominate destination of
transported honey bee colonies, in the indicated time period.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service (NASS), Colony Loss Survey (USDANASS, 2018).
How Was the Study Conducted?
When in use, the USDA, National Agricultural Statistics Service (NASS) Colony Loss Survey collected honey bee colony
data quarterly, including the number of colonies located in each State at the start of each quarter. This data was used to
construct colony movement across States between quarters. This study also uses information on payments for pollination services from NASS’ Cost of Pollination Survey, the value of honey production from NASS’ Bee and Honey Inquiry
Survey, and data from the NASS 2017 Census of Agriculture. Statistics for 2017 are used for consistency between the
Census of Agriculture and other NASS surveys.
Honey Bees on the Move: From Pollination
to Honey Production and Back
Introduction
The pollination of up to one-third of the world’s food crops depends at least partially on insects—including
Apis mellifera)
mellifera and more than 20,000 species of native bees (Berenbaum, 2007; Crane
managed honey bees (Apis
and Walker, 1984; Droege and Packer, 2015). Some crops, such as almonds and melons, require pollination to
produce nuts or fruit. For other crops, such as tomatoes, apples, blueberries, cherries, and canola, pollination
boosts yields and can improve produce quality (Burlew, 2019; USDA-ARS, 2017). Farmers growing crops
that depend on animal-mediated pollination either rely on native pollinators, provide their own bees, or pay
beekeepers for pollination services, or a rely on a combination.
Over the past decade, the pollination services market has grown, such that beekeepers now receive about as
much of their income from providing pollination services as from producing honey (USDA-NASS, 2021).
Beekeepers transport their honey bees around the country to meet the pollination demand from farmers,
whose crops flower at different times during the year, while also securing time for the bees to produce honey
in areas rich in forage, such as the Northern Great Plains.
Honey bees face a variety of stressors to their health. These stressors include Varroa mites and other pests,
diseases, pesticide exposure, and lack of forage (Mullin et al., 2010; Otto et al., 2016; Paudel et al., 2015;
Smart et al., 2016; Spivak and Le Conte, 2017). Beekeepers also note that long-distance travel is a stressor
to honey bee health (Melicher et al., 2019). Honey bees can succumb to these stressors, such that the entire
colony (or hive) dies. Overwinter colony loss rates in the pre-Varroa mite era (late 1980s) were anecdotally
estimated at around 15 percent (Burgett et al., 2010; Pernal, 2008; vanEngelsdorp et al., 2007) or 17-20
percent (Johnson, 2010). In the subsequent Varroa mite era, beekeepers in the United States lost about 31
percent of colonies in the 2017-18 winter and 38 percent of colonies in the 2018-19 winter (BIP, 2019).
However, the total number of honey-producing colonies increased from a low of 2.3 million colonies in 2008
to 2.8 million colonies in 2018, despite the rise in colony loss rates (USDA-NASS, 2019a). Intensified colony
management and the creation of new colonies by splitting hives and purchasing new queens has supported
this increase (Alaux et al., 2010; Ferrier et al., 2018; Grünewald, 2010).
Despite the importance of honey bees to fruit, vegetable, nut, and seed production, limited nationwide data
exist on the number of honey bee colonies that pass through each State or region in the course of a year, the
routes these colonies take, and the distances colonies are transported throughout the year. This information is
critical to understanding how travel affects pollination services, honey production, and colony loss. However,
data collection efforts are hampered by the scope and scale of data to be collected, as well as, the highly
mobile nature of the beekeeping industry. In particular, increasing demand for both fruits and nuts that
require pollination and honey (USDA-ERS, 2017; USDA-ERS, 2018) provides incentives to keep productive
honey bees on the move. This movement challenges data collection, as pollination services are often provided
in one State (e.g., almonds in California) while foraging activities that support commercial honey production,
often take place in another location or even State (e.g., grasslands in North Dakota). As the demand for pollination services grows, so do the links between these regions (Champetier et al., 2019b).
The interdependence of crop pollination in one State on forage resources in another has potential implications for Federal policy. For example, USDA’s Conservation Reserve Program (CRP)—which is concentrated
in the Northern Great Plains Region where 30 percent of beekeepers bring their honey bee colonies in the
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summer—gives farmers incentives to take sensitive land out of agricultural production and plant species
that improve environmental quality. Beekeepers actively target CRP land when selecting apiary sites partly
because of the abundance of floral resources and lack of pesticide exposure associated with lands enrolled in
some CRP programs (Gallant et al., 2014; Otto et al., 2018; Ricigliano et al., 2019). Accordingly, honey bee
pollinator-supporting CRP acreage in one region can help support the production of pollinator-dependent
crops in another region (Ricigliano et al., 2019). The 2018 Agricultural Improvement Act, also known as the
2018 Farm Bill, raised the CRP enrollment cap from 24 million acres in fiscal year (FY) 2018 to 27 million
acres in FY 2023, potentially increasing the amount of forage available to honey bees and other pollinators.
While there is much anecdotal evidence on the pollination routes taken by beekeepers, until now there has
been no quantitative analysis of honey bee colony movements beyond those targeted toward supporting
the California almond pollination market (Goodrich et al., 2019). Bond et al. (2014) provided a qualitative
analysis of pollination routes, determined mainly through conversations with beekeepers and USDA’s Natural
Resources Conservation Service (NRCS). However USDA’s National Agricultural Statistics Service (NASS)
(USDA-NASS, 2018) survey of beekeepers facilitates the tracking of colony movements by quarter and State
for an entire year, providing a comprehensive, quantitatively-based picture of where commercial hives travel.
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Background
Honey bees are social insects that live together as a colony, typically consisting of a single queen bee, tens of
thousands of female worker bees, and hundreds of male drones. In addition to honey bees, a handful of other
managed insects provide pollination, including leaf-cutting bees (non-honey producing bees) and bumble
bees, which are largely used in greenhouses. The contribution of wild pollinators, such as butterflies, moths,
birds, bats, and more than 20,000 species of native bees, is significant (Droege and Packer, 2015). As opposed
to wild pollinators, honey bees can be managed by a beekeeper who provides the woodenware (e.g., boxes
and frames for hives), manages honey collection, treats for diseases and mites, and controls colony size and
numbers through hive size manipulations.
Historically, wild pollinators and locally managed honey bees pollinated nearby crops (Walker, 2020). The
increase in field size and practice of monoculture means that large growers are less able to rely solely on
wild pollinators, which require diverse forage resources and nesting habitat and have a shorter flight radius
than honey bees for their pollination needs (MacDonald et al., 2013). Almond orchards are an example of
large-scale monoculture of a pollinator-dependent crop. Over the last four decades, as the almond industry
underwent significant expansion, demand for pollination services grew. At the same time, U.S. honey prices
were trending lower—and an increasing number of beekeepers had incentives to shift focus from lowervalue honey production towards providing potentially higher-value pollination services (Champetier et al.,
2019a). The California almond bloom typically takes place when hives are overwintering in forage. Thus,
the transport of honey bees, the rise in the demand for commercial honey bee services, and the expansion of
California almond acres are all closely linked (Goodrich, 2019a; Bond et al., 2014).
The movement of honey bee colonies around the country is driven primarily by two factors: The demand by
crop growers for pollination services in different parts of the country, and beekeepers’ demand for forage to
produce honey and ensure overwinter survival of colonies. Farmers who plant crops that require or benefit
from supplemental pollination, such as almonds, typically pay beekeepers to pollinate their crops. After pollinating one crop, the beekeepers typically transport their colonies to the pollination service job, often apples
or cherries which are in bloom nearby following the almond bloom, or move their colonies to landscapes
that provide forage. For this second reason, the demand for good forage to produce honey drives beekeepers
to move their colonies after crop pollination season to forage-rich areas of the country where honey can be
produced, and the colony numbers can grow before the next pollination season begins.
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Honey Bees Provide Pollination Services for Geographically
Diverse Crops
While some growers maintain their own honey bee colonies, many growers rely on renting hives from
commercial beekeepers. Beekeepers transport their honey bees around the country to meet pollination
demands from farmers, whose crops flower at different times during the year. Pollination season starts with
almond pollination in February, when upwards of 68 percent of all commercial U.S. honey bee colonies are
used in California to pollinate almonds (Goodrich et al., 2019; USDA-NASS, 2018).
In 2017, U.S. farmers paid $320 million for pollination services (USDA-NASS, 2017). Almond producers
alone accounted for 80 percent of that amount while the apple and blueberry industries paid almost $10
million each. In 2019, pollination service fees are estimated by USDA, NASS to total $309 before falling to
an estimated $254 million in 2020, with almond pollination fees still accounting for the bulk of fees (USDA,
NASS, 2020). Beekeeper revenue generated directly from the provision of pollination services varies considerably across regions and States, a function of the intensity of use of pollination services, fees charged (typically
on a per colony/hive basis), and concentrations of crops produced (table 1).
The scale and early timing of almond pollination requires a large-scale effort by beekeepers to bring colonies out of dormancy and quickly replenish bee stocks to meet contractual obligations. Almond acreage
has increased rapidly over the past decade, and pollination service fees for almonds have risen in response,
partly because beekeepers must come from further afield to meet the growing demand for honey bees from
California almond growers (see box on Almond Pollination Service Fees) (Goodrich et al., 2019). Also, while
most crops require one strong colony per acre for adequate pollination, almond trees require two colonies
per acre (Champetier et al., 2019a; Phillips, 2019). The combination of these factors contributed to the rising
cost share of almond pollination. Pollination services fees accounted for about 7 percent of a representative
almond orchard’s costs of production in 1998 and have risen to close to 16 percent in 2018 (Champetier et
al., 2019a). The pollination cost share is comparable to that for irrigation, which averaged about 16 percent in
2018 and is slightly less than the harvest cost share of 20 percent (Champetier et al., 2019a).
Supply and demand drive the pollination fees charged by beekeepers. Influential factors include the distance
commercial bee colonies must travel to service a pollination contract, the length of time colonies are rented,
and the marketability of the resulting honey production, all of which varies by crop (Bond et al., 2014;
Goodrich, 2019a; Rucker et al., 2012). For example, honey produced from almond pollination is generally lower value as it tends to be bitter and is considered to be non-palatable for direct human consumption
(though it does have some commercial use as an ingredient in brewing and baking). In part, beekeepers
charge higher fees to pollinate almond orchards to compensate for the generally lower commercial value of
the resulting honey that is produced. Higher fees are also charged for almond pollination in order to partially
offset the higher costs associated with preparing hives to pollinate the crops relatively early-season bloom time
that takes place between January to late March (Bond et al., 2014).
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Table 1
Estimated beekeeper revenue generated from pollination services, by State where pollination
occurred, 2017
State
California
Washington
Pollination
revenue ($1,000)
State
Pollination
revenue ($1,000)
State
Pollination
revenue ($1,000)
271,505
Alabama
395
Oklahoma
127
12,638
Missouri
389
Connecticut
109
Michigan
4,410
New Mexico
341
Vermont
99
Oregon
3,891
Indiana
334
New Hampshire
84
Wisconsin
3,240
Virginia
332
West Virginia
79
Florida
3,032
Illinois
329
Montana
67
Georgia
2,479
Utah
311
Iowa
42
Texas
2,076
Minnesota
301
Nebraska
32
Massachusetts
1,948
Maryland
290
Kansas
27
Maine
1,795
Ohio
263
South Dakota
17
New York
1,623
Arkansas
220
Rhode Island
14
North Carolina
1,500
Idaho
196
Nevada
11
New Jersey
1,324
Delaware
191
Hawaii
5
Arizona
1,229
Tennessee
163
Wyoming
4
Pennsylvania
776
Kentucky
154
North Dakota
3
Mississippi
525
Colorado
141
Alaska
1
South Carolina
406
Louisiana
133
Note: The Cost of Pollination Report (USDA-NASS, 2017) gives beekeeper pollination revenue only at the regional level. Beekeeper
pollination revenue (equivalent to the cost of pollination services paid by crop producers) by State was estimated using the average
cost of pollination per acre from the Cost of Pollination Report (USDA-NASS, 2017) and data on bearing and planted acres by crop in
each State from the Census of Agriculture (USDA-NASS, 2019b). Since not all growers pay for pollination services, we multiply State
crop acreage by the average ratio of paid pollinated acres to total acres for each pollinated crop in the region. This adjusted crop
acreage number is then multiplied by the region-level average cost of pollination per acre for the specific crop to yield the total cost
of pollination for each crop in each State. The figure above shows total estimated pollination revenue in each State.
Sources: USDA, Economic Research Service calculations based on USDA, National Agricultural Statistics Service (NASS) Cost of
Pollination Report (USDA-NASS, 2017) and Census of Agriculture (USDA-NASS, 2019b).
California leads all States in total fees crop producers paid beekeepers for pollination services, with growers
paying more than $270 million to beekeepers for pollination in 2017. Washington and Michigan are the
second- and third-largest source of pollination service fees at $12.6 million and $4.4 million. These States are
associated with a large share of berry and tree fruit production for which fruit set is enhanced via commercial pollination. Melons (e.g., cantaloupe, honeydew, and watermelon) are grown mainly in the South and
California. Demand for pollination services for these crops draws colonies to these regions each spring.
Regional pollination service trends track closely with State-level findings (table 2). Regions 6 and 7, which
includes California—by far the State that spends the most on pollination—spent more than 10 times the
amount of any other region on pollination services in 2017 and accounted for 85 percent of total service fees
paid. While the combined number of acres pollinated in regions 6 and 7 is significantly higher than other
States and accounts for 64 percent of total pollinated acres, the total amount spent on pollination services is
greatly magnified by the relatively high average service fees per colony. In regions 6 and 7, the average price
per colony in 2017 is estimated at $146.20 and is nearly double the next highest average fee of $74.30 per
colony paid in region 1.
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Table 2
Total amount paid for pollination services in 2017 by region1
Region
Region 1
Total acres
pollinated
Price per acre
Colonies used
Price per colony
Total cost of
pollination
(acres)
(dollars)
(colonies)
(dollars)
(1,000 dollars)
232,850
62.40
221,500
74.30
16,450
Region 2
91,200
55.70
106,600
56.20
5,990
Region 3
50,500
55.50
150,300
45.50
6,843
Region 4
7,350
36.10
18,100
47.20
855
Region 5
Regions 6 and 7
U.S. Total
245,150
65.20
333,800
50.10
16,726
1,122,250
239.00
1,865,300
146.20
272,740
1,749,300
319,604
1Notes:
Region 1 includes Connecticut, Illinois, Indiana, Iowa, Kansas, Massachusetts, Maine, Michigan, Nebraska, New Hampshire,
New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, and Wisconsin.
Region 2 includes Alabama, Delaware, Georgia, Kentucky, Maryland, North Carolina, South Carolina, Tennessee, Virginia, and West
Virginia.
Region 3 includes Arkansas, Florida, Louisiana, Missouri, Mississippi, New Mexico, Oklahoma, and Texas.
Region 4 includes Colorado, Minnesota, Montana, Nevada, North Dakota, South Dakota, Utah, Wyoming; Region 5 includes Alaska,
Idaho, Oregon, and Washington.
Regions 6 and 7 includes Arizona, California, and Hawaii.
Source: USDA, Economic Research Service calculations based on USDA, National Agricultural Statistics Service data.
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Crop Dependency for Commercial Honey Bees for Pollination
Varies Greatly by Crop and Region
A diverse array of crops benefit from commercial pollination services that are employed to enhance production. Individual crop physiology and other factors influence the level of dependency on commercial honey
bees to ensure proper fertilization by transferring pollen from flower stamens to the flower stigma (USDA,
ARS, 2017). Among the other factors that influence a crop’s dependency on honey bees are:
• the degree to which abiotic (not living) processes, such as wind, are available and effective in pollinating a particular crop,
• the accessibility of substitute pollination aides such as bats, wasps, butterflies, or mechanized and hand
pollination, and
• the prevalence of less pollinator-dependent cultivars (such as self-pollinating almond trees).
Growers will generally use managed pollinators when wild pollinators and other abiotic processes are not
enough to support the desired level of pollination (Narges and Lippert, 2019). Based on data from USDA,
NASS’ Cost of Pollination Report, dependency-influencing factors vary by region. These factors support
varying levels of demand for commercial pollination services, not just in aggregate (as noted above), but also
for specific crops (table 3). For example, the share of apple-bearing acres that pay for pollination services
ranges from a high of 75 percent (region 1) to a low of 36 percent (region 4).
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Table 3
Percent share of bearing or planted acres that pay for pollination services (top row) and average
pollination service fee paid per colony (bottom row), by crop in U.S. dollars, 2017
Northeast
Region 1
Southeast
Region 2
South
Region 3
Midwest and
Mountain
Region 4
Pacific
Northwest
Region 5
Pacific
Southwest
Regions 6 and 7
Almond
88%
$171
Apple
Blueberry
75%
71%
36%
70%
56%
$71
$52
$50
$52
$45
60%
71%
47%
67%
44%
$77
$56
$58
$45
$106
50%
58%
$64
$55
Cantaloupe
67%
$45
Cherry
77%
55%
$57
$31
Cranberry
80%
100%
$78
$75
Cucumber
71%
80%
$53
$71
45%
60%
14%
21%
$67
$51
$16
$40
Peach
8%
73%
$40
$46
Pear
58%
$56
Pumpkin
15%
28%
73%
$76
$67
$52
Raspberry
Squash
Watermelon
Total
56%
92%
$33
$44
26%
46%
37%
$68
$47
$29
34%
51%
42%
99%
91%
$78
$60
$56
$50
$39
57%
49%
37%
45%
69%
86%
$74
$56
$46
$47
$50
$146
Notes: Bearing acres refer to mature orchard tree acreage, while planted area describes row crop sowings. The top number is the
share of acres that use pollination services while the bottom number refers to the average service fee paid per colony.
Results are reported using the same regions as in the USDA, NASS Cost of Pollination Report. Those regions are numbered 1-7.
Northeast (region 1) includes Connecticut, Illinois, Indiana, Kansas, Massachusetts, Maine, Michigan, Nebraska, New Hampshire,
New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, and Wisconsin.
Southeast (region 2) includes Alabama, Delaware, Georgia, Iowa, Kentucky, Maryland, North Carolina, South Carolina, Tennessee,
Virginia, and West Virginia.
South (region 3) includes Arkansas, Florida, Louisiana, Missouri, Mississippi, New Mexico, Oklahoma, and Texas.
Midwest and Mountain (region 4) includes Colorado, Minnesota, Montana, Nevada, North Dakota, South Dakota, Utah, and
Wyoming.
Pacific Northwest (region 5) includes Alaska, Idaho, Oregon, and Washington.
Pacific Southwest (regions 6 and 7) include Arizona, California, and Hawaii.
Source: USDA, Economic Research Service calculations based on USDA, National Agricultural Statistics Service data.
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The shares noted in the table could be considered similar to a measure of the dependency of a specific crop,
in a particular region, on commercial honey bees to facilitate pollination. This measure is comparable to
other “dependency ratios,” such as those published by Morse and Calderone (2000). Our measure contributes to the literature by considering regional variation in the intensity of pollinator use by crop, as opposed
to reporting a national average level of commercial pollinator dependence. Further, our measure compares
the number of acres known to be pollinated (from USDA, NASS’ 2017 Cost of Pollination Report) with
the number of bearing or planted acres (from the USDA, NASS Census of Agriculture) in the same region,
returning the share of bearing (mature orchard tree) or planted (row crop) acres that paid for pollination by
crop and by region. It should be noted that our ratio is calculated for crops produced in 2017 and represents
a snapshot in time. The intensity of use of pollination services likely varies from year to year, based on fluctuating agronomic and economic conditions. Considering this expectation, improved measures of dependency
on pollination services should be averaged over a period of years. It is also recognized that the intensity of use
of pollination services is distinct from the relative attractiveness of agricultural crops for nectar and pollen
gathering by pollinating insects. For insights into the relative attractiveness measures, please see the USDA
report Attractiveness of Agricultural Crops to Pollinating Bees for the Collection of Nectar and/or Pollen (USDA,
2017).
The regional differences in intensive use levels are likely attributable to several factors—both economic and
environmental. Apple pollination service fees in region 1 are the highest of all regions and are nearly $20 per
colony higher than for the next most expensive region. Pollination fees are likely higher in this region as apple
producers in region 1 are likely to be competing for hives from the far-larger area (in terms of bearing acres)
of apple and pear production in the Pacific Northwest (region 5). Hive availability may also be a factor, as
well as the relative availability of wild pollinators.
Other crops with large regional variation in the share of paid pollination acres include peaches (ranging
from 8-73 percent), pumpkins (15-73 percent), watermelons (34-99 percent), and blueberries (44-71 percent).
Across all regions, it is expected the supply of wild pollinators and local honey bees is likely to influence
how many honey bee colonies need to be transported from outside the area. Generally, for specific crops and
regions that indicated a low level of dependency on commercial pollination services, the associated pollination fee is relatively low. Some examples of this are cucumbers in regions 3 and peaches in region 2.
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Almond Pollination Service Fees
Almond bearing acres reached nearly 1.1 million in 2018 (figure 2)—up from 710,000 acres in 2008—
representing a 54-percent increase in the last 10 years. In 2018, the rental fee for a single honey bee
colony for almond pollination ranged between $165 and $210, with an average rate of approximately
$190 (California State Beekeepers Association, 2019). This is a significant increase from the $76 percolony rental rate for almonds in 2006 (Bond et al., 2014) ahead of a hike in rental rates in 2017. Rental
rates also depend on colony strength or the number of bees in a colony with strong hives (measured by
frame counts), commanding a premium over smaller hives. Colony strength may be affected by overwinter
survival rates and thus influence per colony rental rates accruing to the beekeeper. Lower strength colonies
(fewer than eight frames) will bring in lower pollination service fees during the February almond bloom
as pollination contracts increasingly have a strength requirement and/or per-frame bonuses (Goodrich,
2018). In a related study, Goodrich (2019b) estimates that beekeeper revenue from almond pollination
will fall 16 percent for every 10 percent increase in hive overwinter mortality rates. Greater overwinter
mortality rates can result in smaller hives and, all else being equal, rental rates tend to be less for smaller
hives. If a beekeeper’s average hive size declines because of increasing overwinter mortality rates, this can
cause lower rental rates and returns. The value of almond production was more than $5.6 billion in 2017,
making it the seventh most valuable crop in the United States (USDA-NASS, 2019c). The bearing acreage
is projected to continue to rise, as there are approximately 300,000 non-bearing acres that will mature into
almond production in the next 3-4 years (USDA-NASS, 2019d). As these non-bearing acres begin to bear
almond flowers, more honey bees will be needed for pollination.
Figure 2
Pollination fees and almond bearing acres in California from 2007-18
Bearing Acres (1,000)
1,200
Fee per colony (dollar)
250
Almond pollination fee (left axis)
1,000
200
800
150
600
100
400
Bearing Acres (right axis)
50
0
200
0
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Note: Pollination service fees are reported in nominal dollars and have not been adjusted for inflation.
Sources: USDA, Economic Research Service calculation based on USDA, National Agricultural Statistics Service Quick Stats data;
and the California Beekeepers Association.
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Honey Production Linked to Forage Resource Access
Managed honey bees collect nectar and pollen from flowering plants and produce and store honey inside of
hives on frames that can be removed by the beekeeper. Honey production and other products respectively
provided $333 million and $95 million in revenue to beekeepers in 2018 (USDA-NASS, 2019a).1
While honey production and foraging activities are closely linked, colonies that provide pollination services
do not always produce marketable honey. For example, the honey produced when bees forage during the
almond bloom has limited commercial value. In contrast, bees that forage on clover produce a sweeter honey
that consumers prefer. Honey bees feed on the honey they produce, and beekeepers must decide how much
honey to pull from a colony without jeopardizing colony survival. Pulling too much honey can result in the
loss of the colony or a weaker colony. To help strengthen colonies, especially during the winter months when
forage resources are low, some beekeepers supplement honey supplies with feed in the form of sugar water or
fondant.
Figure 3
Value of honey production by State, 2018
Total honey production
(in million dollars)
Less than 2
2-5
5 - 15
15 - 25
25 - 72
Note: Honey colonies that produced honey in more than one State were counted in each State where the honey was produced.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service (NASS) data from the
Honey Report (USDA-NASS 2019a).
Good forage resources are typically associated with higher volumes of honey production. North Dakota and
other States in the Northern Great Plains—including South Dakota, Montana, and Minnesota—are known
for their foraging grounds. A combination of a short growing season, ample precipitation, and cooler temperatures result in a burst of flowering plants over the summer that beekeepers seek out for their colonies. Not
1Other
colonies.
products included in the annual USDA, NASS Honey Report include: honey bee queens, packaged bees, and nucleus
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surprisingly, North Dakota leads the Nation in honey production, while Montana, Florida, and California
are also major producers (figure 3). In terms of value, more than 20 percent of U.S. honey in 2018 was
produced in North Dakota. Typically, between spring and summer, the number of honey bee colonies in the
Northern Great Plains has been observed to more than quadruple (table 4).
When honey bee colonies are crowded together, competition for forage resources can result in a decline in
honey production and colony health (Abbott, 2018). South Dakota, Montana, Wyoming, Arkansas, and New
Mexico require exclusion zones or buffer areas around registered apiary sites to protect the forage resources.
During the summer months, when almost a third of all colonies are moved into the Northern Great Plains,
there is a 3-mile exclusion zone in South Dakota and Montana; Wyoming has a smaller 2-mile exclusion zone
and North Dakota has none. Smaller exclusion zones mean that relatively more hives can be placed to forage
on a given parcel of land. This partly explains why North Dakota annually draws an estimated 40 percent of
all commercial hives to the forage opportunity rich State (Smart et al., 2016).
Table 4
Honey bee colony stocks by State
Honey bee colonies
Summer
(July 1, 2017)
Fall
(October 1, 2017)
Winter
(January 1, 2018)
California
590
680
1,150
State
Spring
(April 1, 2018)
1,140
North Dakota
470
410
64
72
Florida
176
180
245
270
Montana
154
115
35
50
South Dakota
152
111
23
11
Minnesota
136
98
39
69
Georgia
121
125
134
134
Texas
104
127
205
305
Michigan
103
88
17
36
Oregon
94
94
81
41
Idaho
89
113
164
60
Washington
82
66
44
55
Wisconsin
74
51
21
24
Louisiana
64
58
50
48
New York
59
51
26
20
Nebraska
46
42
7
11
Iowa
40
45
41
45
Colorado
35
34
13
17
Utah
35
29
8
15
Wyoming
Other
United States
35
28
6
9
336
305
260
263
2,995
2,850
2,631
2,693
Note: Numbers in bold represent the season in each State with the most honey bee colony stocks.
Source: USDA, Economic Research Service using data from the USDA, National Agricultural Statistics Service (NASS), Honey Bee
Colonies report (USDA-NASS, 2018)
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The Northern Great Plains also features a concentration of acres (about 21 percent of the total) that are
enrolled in the USDA, Farm Service Agency’s CRP (figure 4). Some, but not all, of this CRP land is prime
for honey bee forage. Beekeepers seek out places with quality forage and a low risk of chemical exposure;
often, CRP land meets these criteria. Further, North Dakota is also noted for its pollinator-friendly spans of
uncultivated grasslands and wetlands, especially in the Prairie Pothole Region. Smart et al. (2016) found that
placing honey bee colonies on these areas of uncultivated forage land—including pasture, USDA conservation program fields, fallow land, grassland, hay land, and roadside ditches in North Dakota—had “a positive impact on annual apiary survival and honey production” relative to colonies in areas with agricultural
production.
Both honey bees and wild pollinators benefit from programs that increase forage resources, such as certain
practices supported under CRP. In addition to supporting the establishment of grasslands (the most common
practice), USDA’s Farm Services Agency also specified several pro-pollinator programs (Gallant et al., 2014;
Otto et al., 2018; Ricigliano et al., 2019). The USDA, Natural Resources Conservation Service (NRCS)
also has targeted conservation efforts in this area of the country and reports that 35,000 acres of land
have been enhanced through their efforts (USDA, NRCS, 2016a). One such program, the USDA, NRCS
Environmental Quality Incentives Program (EQIP), has 37 conservation practices that can be used by landowners to create or enhance pollinator habitat. Some practices include planting cover crops, planting wildflowers and native grasses in buffers, and improving management of grazing lands (USDA, NRCS, 2016b).
The Conservation Stewardship Program (CSP) and Agricultural Conservation Easement Program (ACEP)
also are aimed at helping landowners and producers to implement conservation practices, some of which
benefit pollinators (USDA, NRCS, 2019).
Figure 4
Enrolled acres by county in the USDA Conservation Reserve Program, September 2018
Area in acres
< 10,000
10,001 - 25,000
25,001 - 75,000
75,001 - 150,000
150,001 - 261,130
Note: 22.6 million total acres enrolled in the USDA Conservation Reserve Program in September 2018.
Source: USDA, Economic Research Service calculations using data from the USDA, Farm Service Agency (USDA-FSA, 2019).
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Following Honey Bee Colonies Through the Seasons
In 2015, USDA, NASS began surveying beekeepers with five or more colonies about colony health to build
a body of knowledge on honey bees in the United States (USDA, NASS, 2018). The USDA, NASS Colony
Loss Survey collects honey bee colony data from a panel of beekeepers quarterly, starting in the third quarter
(the first month is July) and ending in the second quarter of the following year (the first month is April). As
part of the survey, beekeepers indicate in which State their colonies were in that quarter. Combining data
from multiple quarters allows for the tracking of movements of colonies by quarter and State.
The 2017 and 2018 USDA, NASS Colony Loss Survey report summarizes the quarterly responses of
beekeepers to several questions, including colony locations at the time of the survey. For beekeepers who
kept their colonies in the same location during a particular quarter, it is known where each of these colonies
came from and where they went. A majority (97-98 percent) of the 14,532 beekeepers included in the 2018
survey report that they do not move colonies from multiple States to multiple States from quarter to quarter.
For these beekeepers and colonies, it is known from which States they came and to which States they go.
However, for the 2 to 3 percent of beekeepers reporting colonies in different States within a quarter, it is only
known from where these honey bee colonies came if, in the prior quarter, that beekeeper only had colonies in
a single State (or where they went if the beekeeper in the next quarter only had colonies in a single State).
For example, suppose a beekeeper has colonies in California, Montana, and Washington and moves them to
North Dakota and South Dakota the following quarter. In that case, the data do not specify which colonies
moved from California to North Dakota. To address the tracking issue with a relatively small proportion of
our survey data, proportionality in colony movements is assumed. Using the example above, if beekeepers
split their colonies evenly between North Dakota and South Dakota in the following quarter, it is assumed
that half of all the colonies in California, Montana, and Washington moved to North Dakota and the other
half moved to South Dakota. These movements are summarized by State and by region (described in table 5).
Regions were chosen to be representative of the pollinated crops, forage, and colonies in these locations.
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Commercial Honey Bee Movements Are Strongly Seasonal
Two events dominate the movement of honey bee colonies around the United States: An influx into
California for almond pollination in February and outflow into the Northern Great Plains for access to highquality forage in the summer. A small minority of colonies remains in the same State throughout the year.
Table 5 shows the number of resident and transitory colonies in select States on the first of January (winter)
and the first of July (summer). Resident colonies are those that were in the State for the first half of the year
and on the indicated date, 6 months later (e.g., the hive was in the State for a full year), while transitory colonies were in different States on each survey date.
At the beginning of 2018, almost half of the colonies in California had been in California since July 1, 2017.
These 540,000 resident colonies remained in California for the second half of 2017 or left and returned
within that period. Further, these commercial honey bee colonies, that likely were in position to aid in the
early spring almond pollination, were also available to supplement the smaller scale use of other wild and
managed pollinators in the pollination of alfalfa (July), melons (August), sunflowers (August), and squash
(September). Resident California colonies may also produce honey during the summer months when colonies
are not foraging in almond orchards. According to the Honey Report (USDA, NASS, 2019a), honey was
pulled from 335,000 colonies in California in 2018. States with the greatest summer influx of non-resident
or transitory colonies include those in the Northern Great Plains, such as North and South Dakota—where
432,000 and 140,000 colonies, present on July 1, were not in those States on January 1—representing more
than 90 percent of colonies in those States.
Table 5
Transitory and resident honey bee colonies in the summer and winter for select States
Region
State
Colonies on July 1, 2017
Summer
Colonies on January 1, 2018
Winter
Transitory
(in other State
on January 1, 2017)
Resident
(in same State
on January 1, 2017)
Transitory
(in other State
on July 1, 2017)
Resident
(in same State
on July 1, 2017)
California
California
11,100
578,800
609,900
540,000
West
Colorado
26,300
8,600
3,800
9,200
Nevada
Oklahoma
Utah
Wyoming
South
D
D
D
2,600
16,100
D
20,200
14,800
0
7,500
D
D
D
D
Arizona
1,300
24,700
2,800
22,100
Louisiana
1,200
62,700
D
49,900
New Mexico
D
D
D
D
2,200
101,700
174,800
30,200
D
6,300
D
7,000
Florida
16,100
159,900
88,900
156,100
Georgia
7,600
113,400
29,500
104,500
Mississippi
1,600
22,400
9,600
9,400
North Carolina
7,000
18,900
1,200
17,200
South Carolina
1,100
13,400
3,100
10,400
Tennessee
1,000
9,000
D
9,300
Texas
Southeast
D
1,800
Alabama
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Region
Pacific
Northwest
Northern
Great Plains
Midwest
Northeast
State
Colonies on July 1, 2017
Summer
Colonies on January 1, 2018
Winter
Transitory
(in other State on
January 1, 2017)
Resident
(in same State on
January 1, 2017)
Transitory
(in other State
on July 1, 2017)
Resident
(in same State
on July 1, 2017)
32,500
56,400
94,500
69,500
Oregon
27,600
66,400
14,700
66,200
Washington
25,700
56,300
18,800
25,200
Minnesota
103,800
32,200
14,200
24,700
Montana
132,900
21,100
4,100
30,800
North Dakota
431,600
38,300
16,600
47,400
South Dakota
139,500
12,500
8,500
14,500
Arkansas
10,000
18,900
3,000
18,900
Illinois
1,400
11,500
D
9,600
Indiana
6,800
6,100
D
6,800
Iowa
Idaho
25,600
14,400
8,200
32,800
Kansas
1,300
5,700
D
3,600
Kentucky
1,600
7,300
600
4,900
Missouri
Nebraska
400
38,700
8,600
7,300
1,100
D
6,800
5,700
D
2,900
D
2,400
Connecticut
Delaware
D
D
D
D
Maine
3,700
1,700
0
1,900
Maryland
1,400
7,000
2,700
5,300
Massachusetts
6,400
2,500
D
2,900
Michigan
79,000
24,000
1,600
14,800
D
D
D
D
New Jersey
New York
7,900
27,800
8,100
31,100
500
2,100
5,900
23,900
Ohio
4,600
18,400
600
11,400
New Hampshire
Pennsylvania
2,100
16,400
600
13,800
Rhode Island
Vermont
D
2,000
D
5,400
D
200
D
5,300
Virginia
2,300
9,200
900
6,000
West Virginia
3,600
5,400
1,000
3,700
Wisconsin
52,000
21,900
1,500
19,400
Notes: D = Estimates less than or equal to 1,000 not shown to avoid disclosing data for individual operations. Data rounded to
nearest 100 colonies.
Source: USDA, Economic Research Service analysis using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
Figure 5 shows the movement into California from July 1, 2017, to January 1, 2018. The largest share of colonies that move into California in this time period come from the Northern Great Plains (384,600 colonies).
Two adjacent regions, the West and Pacific Northwest, are also important sources of colonies for California.
Almost 39,000 colonies come from as far away as the Northeast. Another dataset of honey bee colony movement into California, from the California Department of Food and Agriculture (CDFA) (2019), is discussed
in the box titled Honey Bee Colonies Entering California.
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Figure 6 shows the movement out of California from January 1, 2017, to July 1, 2017. Again, most colonies
(473,000) moving out of California are destined for the Northern Great Plains. An additional 73,000 colonies went to the neighboring Pacific Northwest, while 51,000 more headed to the region labeled “West”.
In the first 6 months of the year, almost 55,000 colonies from the West Coast went to the Northeast and
Southeast regions.
Figure 5
Honey bee colony movements into California from July 1, 2017 - January 1, 2018
Pacific Northwest
Northern Great Plains
West
Northeast
Number of
colonies
Midwest
384,600
California
65,600
62,900
38,500
Southeast
South
29,900
D
D
Notes: D = Estimate not shown to avoid disclosing data for individual operations. The width of the arrows is proportional to the
number of colonies moved; line curvature is indicative of non-linear route paths. Hawaii and Alaska are excluded from this route map
as local colonies are not indicated to travel to or from these States to other regions in the continental United States. Orange colored
areas represent the predominate destination of transported honey bee colonies, in the indicated time period.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
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Figure 6
Honey bee colony movements out of California from January 1, 2017- July 1, 2017
Northern Great Plains
Pacific Northwest
West
Northeast
Midwest
California
Southeast
South
Number of
colonies
473,500
73,400
50,800
40,100
29,000
14,400
3,700
Note: The width of the arrows is proportional to the number of colonies moved; line curvature is indicative of non-linear route paths.
Hawaii and Alaska are excluded from this route map as local colonies are not indicated to travel to or from these States to other regions in the continental United States. Orange colored area represents the origin of transported honey bee colonies, in the indicated
time period.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
Honey Bee Colonies Entering California
Honey bee colonies entering California are subject to two inspections, a cursory one at the border and
a more detailed inspection at the destination (CDFA, 2019). The California Department of Food and
Agriculture (CDFA) conducts the inspections and maintains records of the number of honey bee
colonies entering California, as well as the State of origin. According to data from the CDFA, about
915,000 colonies entered California in the second half of 2017 (CDFA, 2019). This is more than the
610,000 colonies estimated as having entered during the same period, based on NASS data from the
USDA-NASS Honey Bee Colonies report (table 4).
The discrepancy likely arises because only those colonies entering California before July 1, 2017 are
captured. Some colonies may have left California after July 1, 2017 and re-entered sometime before
the end of the year. These colonies are not captured in our estimates, whereas these colonies would be
counted in the CDFA data. Our estimate of 610,000 colonies entering California in the second half of
2017 is combined with the 540,000 colonies that were already in the State. Our aggregate estimate of
the total number of colonies (1.15 million) in the State matches that on January 1, 2018, published by
USDA’s National Agricultural Statistics Service (NASS) (USDA-NASS, 2018) and presented here in
table 4.
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The Northern Great Plains is one of the main destinations for honey bee colonies in the summer, and figures
7 and 8 show colony movements into and out of this area for the summer of 2017. In addition to 473,000
colonies from California, another 189,000 colonies came from Texas and other States in the South. That
colonies are moved to the Northern Great Plains in the summer, despite the relative lack of demand for paid
pollination services in the region, indicates that beekeepers bring the colonies mainly to forage rather than
paid pollination work; the region including the Northern Great Plains accounts for less than 1 percent of
total paid pollination services in 2017.
After the summer and ahead of the cold winter months, most honey bees are moved out of the Northern
Great Plains and into warmer States in the South. Some honey bees can overwinter in the North in heated
warehouses. Heated potato cellars—which are protected from the harsh northern weather—are an overwintering option for some colonies in some Northern States. However, not all colonies travel along these major
routes into California in the winter and into the Northern Great Plains in the summer. About 58 percent
of all colonies do not leave their region between July and January of the following year. Of the colonies that
do move regions between July and January, 47 percent move into regions other than California. Beekeepers
transported about 95,200 colonies from the Northeast into the Southeast for the winter of 2018 and another
24,500 colonies from the Northeast into the South. Finally, about 15,900 colonies from the Southeast and
11,100 colonies from the South moved into the Midwest for the summer of 2017.
Figure 7
Honey bee colony movements into the Northern Great Plains from January 1, 2017-July 1, 2017
Northern Great Plains
Pacific Northwest
Northeast
West
Midwest
Southeast
Number of
colonies
473,000
188,800
92,700
South
22,400
19,300
D
D
Notes: D = Estimate not shown to avoid disclosing data for individual operations. The width of the arrows is proportional to the
number of colonies moved; line curvature is indicative of non-linear route paths. Hawaii and Alaska are excluded from this route map
as local colonies are not indicated to travel to or from these States to other regions in the continental United States. Orange colored
areas represent the predominate destination of transported honey bee colonies, in the indicated time period.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
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Figure 8
Honey bee colony movements out of the Northern Great Plains from July 1, 2017- January 1, 2018
Pacific Northwest
Northern Great Plains
Northeast
West
Midwest
California
Southeast
South
Number of
colonies
384,600
309,400
102,500
D
16,600
D
D
Notes: D = Estimate not shown to avoid disclosing data for individual operations. The width of the arrows is proportional to the
number of colonies moved; line curvature is indicative of non-linear route paths. Hawaii and Alaska are excluded from this route map
as local colonies are not indicated to travel to or from these States to other regions in the continental United States. Orange colored
area represents the origin point of transported honey bee colonies, in the indicated time period.
Source: USDA, Economic Research Service calculations using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
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Colony Health Is Affected by Long-Distance Travel
Transporting commercial honey bees to pollination service and forage grounds often involves long-distance
travel and variable environmental conditions that harm colony health (Melicher et al., 2019). During travel,
honey bees are unable to access foraging resources and are instead fed supplements such as sugar water or
fondant. During the summer, overheating while in transit can become a problem if the hive boxes, often
transported on a flat-bed truck, are not configured for proper ventilation (Melicher et al., 2019).
Four recent studies document the biophysical effects of transportation for pollination services on honey bee
health. Honey bees maturing during transportation have trouble fully developing their food glands that
might affect their ability to nurse the next generation of worker bees (Ahn et al., 2012). Zhu et al. (2014)
found an increase in the abundance and prevalence of the fungal pathogen Nosema ceranae in honey bees
transported for pollination, in contrast to colonies not moved. In a set of field experiments, Simone-Finstrom
et al. (2016) detected a significant decrease in the lifespan, as well as higher oxidative stress levels, in migratory adult bees relative to stationary bees. A more recent study by Melicher et al. (2019) confirms that hives
experience considerable temperature stress and that this should be considered a contributing factor to annual
colony losses.
To help inform research on the impact of travel on honey bee health and colony loss, in this section, the
average distance traveled by colonies within quarters is estimated, as well as over the course of a year. Using
distances between State centroids (mathematical mean or middle of a shape), the total distance colonies
moved throughout the year can be approximated. These calculations rely on the more detailed State-to-State
movement data rather than the region-to-region movement data discussed elsewhere in the report.2 Table 6
shows the average distance traveled by a colony for various pairs of quarters from April 1, 2017, to April 1,
2018—the latest set of quarterly data available from USDA, NASS at the time this research was completed.
The first column shows the average distance for the subset of colonies that were moved out of State across the
pairs of quarters. The second column shows the average for all colonies, including those that remained in the
same State and, therefore, assumed to travel zero miles.
The nature of the data does not allow us to calculate distances traveled by an individual commercial honey
bee colony within a State nor for a full year. However, the average distance between the States in which a
beekeeper moved colonies from one quarter to the next quarter can be calculated. Accordingly, the average,
full-year distance traveled estimate by “All” colonies is 1,153-miles and captures both colonies that were
transported during the year along with colonies that never moved (table 6). Because the total number of
colonies in each State is used in the numerator, the average annual distance traveled by migrating colonies is
likely higher than the 1,153 reported over all the colonies. The annual distance estimate for colonies that have
moved cannot be calculated as the sum of quarterly distance estimates as colonies may have moved during
one quarter but not the next. As such, the “full year” estimate of miles traveled for colonies that have been
moved during at least one quarter cannot be accurately tallied.
2The
here.
underlying State-to-State movement data are not discernible from the national averages of distance traveled that are presented
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Table 6
Estimated average distance traveled by honey bee colonies each quarter from April 1, 2017 to
March 31, 2018
Distance between the States where the colony was on the first day
of the quarter
Average miles for colonies that
were moved
April 1, 2017 – June 30, 2017
Average miles for all colonies
990
July 1, 2017 – September 30, 2017
363
803
113
October 1, 2017 – December 31, 2017
1,014
388
January 1, 2018 – March 31, 2018
1,031
288
-
1,153
Full year
Note: “-“ indicates data are not available.
Source: USDA, Economic Research Service analysis using USDA, National Agricultural Statistics Service, Colony Loss Survey
(USDA-NASS, 2018).
The concentration of almond pollination in California and its location at the edge of the contiguous United
States is one explanation for the long distances honey bee colonies travel throughout the year. The average
distance traveled by colonies coming from various States in October 1, 2017, into California by January 1,
2018, was 1,100 miles, equivalent to a 20-hour drive at 55 miles per hour. Figure 9 shows the percent of colonies moved by the average distance traveled between January 1, 2017, and July 1, 2017. Spikes can be seen in
the bars containing the distance between California and North Dakota, South Dakota, and Montana, as well
as Texas and North and South Dakota. Colonies moved to the East Coast from the West Coast traveled more
than 2,000 miles. Movement between States on July 1, 2017, and January 1, 2018, follows a similar pattern
(figure 10).
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Figure 9
Percent of honey bee colonies that were moved, by the average distance traveled between
January 1, 2017-July 1, 2017
Percent
25
CA-ND
20
CA-SD,
TX-ND
15
10
CA-MT
TX-SD
CA-MN
5
West to East Coast
0
0
500
1000
1500
Average distance traveled by a colony (if moved)
2000
2500
Note: CA=California, MT=Montana, TX=Texas, SD=South Dakota, ND=North Dakota, MN=Minnesota.
Source: USDA, Economic Research Service calculations based on USDA, National Agricultural Statistics Service data.
Figure 10
Percent of honey bee colonies that were moved, by the average distance traveled between
July 1, 2017-January 1, 2018
Percent
20
SD-CA,
ND-TX
ND-CA
15
SD-TX
MT-CA
10
ND-CA
MN-CA
5
East to West Coast
0
0
500
1000
1500
Average distance traveled by a colony (if moved)
2000
Notes: WY=Wyoming, CA=California, MT=Montana, TX=Texas, SD=South Dakota,
ND=North Dakota, MN=Minnesota.
Source: USDA, Economic Research Service calculations based on USDA, National Agricultural Statistics Service data.
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2500
Conclusion
Beekeepers must make complex determinations about whether, when, and where to move their honey bees to
produce honey, service pollination contracts, and provide their honey bees with access to nutritious forage.
Using data from USDA, NASS, our analysis is the first to quantify the seasonal flow of honey bees, as hives
are moved into and out of regions in the United States to pollinate crops and forage over the course of an
entire year. Further, evidence of the intensity of reliance on pollination services is documented to vary, not
just by crop as other researchers have found, but also by region. Significant variances between our surveybased rates of pollination service used and previously published crop-specific dependency ratios suggest more
work is needed to better understand what factors influence farmers’ decisions to employ honey bees to aid in
crop pollination.
In this study, the effect of market factors on the transportation of honey bees is documented. Specifically, the
demand for honey bee colonies to provide pollination services for crops is growing. This demand is driven
primarily by one event, the flowering of almond trees in February in California. Almond acreage has grown
576 percent, from 710,000 acres in 2008 to 1.25 million acres in 2020. The almond bloom is estimated to
employ nearly 1.5 million honey bee colonies, some from as far away as the East Coast. This movement from
honey-producing regions in the summer to other areas of the country to pollinate crops means that honey bee
colonies travel long distances multiple times a year. The average colony is estimated to have moved more than
1,000 miles during the 12-month period starting April 1, 2017.
The largest single source of honey bee colonies for almond pollination is the Northern Great Plains. This
region provides rich forage in the summer, including large areas of CRP-enrolled grasslands and farm acreage.
Beekeepers move their colonies into this region after pollinating crops in the winter and spring, such that
acreage enrolled in CRP in the Northern Great Plains and other uncultivated lands can be characterized as
supporting the production of honey bee-pollinated crops throughout the United States. The Northern Great
Plains foraging colonies also produce nearly half of the honey produced in the United States. In recent years,
however, forage in this region has declined because of increases in corn and soybean acreage and decreases in
acreage enrolled in the Conservation Reserve Program (Hellerstein et al., 2017; USDA, NASS QuickStats,
2019).
Through tracking the wide-ranging seasonal flow of honey bees across the United States while noting the
related stressors placed on the bees, policy discussions concerning honey bee health may be informed.
Further, documentation of seasonal colony movements may be useful in the conversations centered on
State, Federal, and private efforts to assess the provision of forage resources for both honey bees and wild
pollinators.
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File Type | application/pdf |
File Title | Honey Bees on the Move: From Pollination to Honey Production and Back |
Subject | honey bees, honey, pollination, pollinator, honey bee colonies, Apis mellifera, Conservation Reserve Program, CRP, beekeepers, a |
Author | Jennifer K. Bond |
File Modified | 2021-06-17 |
File Created | 2021-06-14 |