More Information

In addition to developing and testing new methods 

for dispersing problem blackbirds, NWRC scientists 

are also documenting habitat use and movements of 

blackbirds throughout the Great Plains. To learn more 

about NWRC’s blackbird research, please visit our 

Web site at www.aphis.usda.gov/wildlifedamage/nwrc.

Wildlife Services Office Phone Numbers

Wildlife Services State Office, Bismarck, ND 

(701) 335-3300

NWRC headquarters (Fort Collins, CO) 

(970) 266-6000

Eastern Regional Office (Raleigh, NC) 

(919) 855-7200

Western Regional Office (Fort Collins, CO) 

(970) 494-7443

Operational Support Staff 

(301) 851-4009

Animal and Plant Health Inspection Service

Program Aid No. 1959

Solutions Through Science

About the NWRC

NWRC is the research arm of USDA’s Wildlife 

Services program. The Center is a leader in 

providing science-based solutions to the complex 

issues of wildlife damage management as related 

to agriculture; natural resources, including 

threatened and endangered species; property and 

infrastructure; and public health and safety. NWRC 

scientists strive to find solutions that are biologically 

sound, environmentally safe, and socially acceptable 

for use in resolving wildlife damage-management 

problems throughout the United States and abroad. 

Often, Wildlife Services’ operational personnel assist 

NWRC scientists in developing and evaluating new 

management tools and methods.

NWRC employs more than 150 scientists and 

support staff at its headquarters in Fort Collins, 

CO, and at field stations throughout the United 

States. NWRC’s scientists have expertise in a wide 

range of disciplines, including animal behavior, 

wildlife biology, wildlife sensory biology, chemistry, 

immunology, statistics, population modeling, 

genetics, toxicology, and veterinary medicine.

Photo credits: The images in this brochure were taken by USDA employ-

ees or are part of the APHIS image collection.

USDA is an equal opportunity provider and employer.

This publication reports research involving pesticides. All uses of pesti-

cides must be registered by appropriate State and/or Federal agencies 

before they can be recommended.

_____________________________________________________________

CAUTION: Pesticides can be injurious to humans, domestic 

animals, desirable plants, and fish or other wildlife—if they are 

not handled or applied properly. Use all pesticides selectively and 

carefully. Follow recommended practices for the disposal of surplus 

pesticides and pesticide containers.

Revised April 2014

www.aphis.usda.gov/wildlifedamage/nwrc

NWRC headquarters in Fort Collins, CO.

“Solutions to problems depend upon 

knowledge, which only research can provide.” 

~ Edwin R. Kalmbach, first Director for the 

predecessor of the NWRC (1940–1954)

Protecting Sunflowers From Blackbirds

United States Department of Agriculture
Researchers from NWRC, University of Minnesota, and 

USDA-ARS are exploring new methods, such as using 

perennial sunflower as a “lure” crop, to reduce blackbird 

damage to sunflowers.

Problem

In late summer, large flocks of blackbirds gather in the 

northern Great Plains to prepare for their strenuous 

migration to southern wintering grounds in the United 

States and Mexico. The birds acquire energy for their 

trip by feasting on nutrient-rich seeds and berries. 

Unfortunately for farmers, many of those seeds come 

from agricultural crops. Red-winged blackbirds, 

common grackles, and yellow-headed blackbirds 

cause most of the damage to commercial crops. 

Sunflower producers in North Dakota, South Dakota, 

and Minnesota suffer millions of dollars in losses 

annually due to blackbirds.

Reducing blackbird damage to sunflower crops 

continues to be a challenge for researchers and 

farmers. Farmers can suffer losses ranging from slight 

to devastating (total crop loss). Blackbirds tend to eat 

a portion of the grain in a field, which lowers the overall 

yield, but their depredation is not often enough to 

trigger an insurance claim.

Birds that congregate in fields in mid-August are 

not easily harassed because they are in the process 

of molting their flight feathers and tend to stay in 

nearby wetlands. It is these birds that can cause the 

most damage.

Science-Based Solutions

To help reduce blackbird damage to commercial 

sunflower crops, scientists at the Bismarck, ND, 

field station of the U.S. Department of Agriculture’s 

(USDA) National Wildlife Research Center (NWRC) 

are collaborating with North Dakota State University 

(NDSU) scientists to better understand the ecology 

and behavior of blackbirds. In particular, scientists are 

studying the effectiveness of various avian repellents 

to protect agricultural crops. NWRC scientists are 

also collaborating with USDA’s Agricultural Research 

Service (ARS) and the University of Minnesota to 

develop a high-yielding strain of perennial sunflower 

that could be used as a lure crop to entice birds away 

from highly valuable commercial crops.

Thinning Cattails

Throughout the Prairie Pothole Region of the Great 

Plains, sunflower crops are often planted near cattail 

wetlands. This arrangement is ideal for blackbirds, as 

they roost in cattails and easily fly short distances to 

feed on nearby sunflowers. One management method 

NWRC and NDSU scientists developed that has proven 

successful at reducing blackbird damage to sunflowers 

is the thinning of adjacent cattails to make them less 

suitable for blackbirds.

Cattails can be sprayed with Government-approved 

aquatic herbicides between mid-July and 

early-September. Herbicides should be applied in 

strips either aerially or with ground-based sprayers. 

The remaining untreated cattails offer habitat for 

other migratory birds that prefer more open wetland 

areas. For more information and guidance on 

the use of aquatic herbicides for cattail thinning, 

please call USDA Wildlife Services in North Dakota 

at (701) 355-3300.

Using Lure Crops

In the early 1980s, NWRC scientists showed that 

planting “lure” crops could significantly reduce bird 

damage to nearby commercial sunflower fields. Due 

to logistical and economic reasons, however, land 

managers did not express much support for the 

concept. Today, the idea of lure crops or “wildlife 

conservation plots” is gaining acceptance.

The concept is simple—plant a small field (about 20 

acres is ideal) of sunflowers or another crop, such as 

corn, that is attractive to blackbirds. Do not spray the 

crop with insecticides, and do not harass the birds 

using it. The goal is to keep the birds in the lure crop 

as long as possible, thereby reducing the time they 

Red-winged blackbirds are 

responsible for the majority 

of wildlife damage to

sunflower crops.

spend in nearby commercial sunflower fields. Each 

seed eaten in the lure crop is one less seed eaten in 

the commercial field. To encourage the birds to stay 

in sections planted with the lure crops, farmers can 

continue to spray registered repellents and harass 

birds in their commercial fields. 

NWRC scientists are finding that the most successful 

lure crops are those planted between wetlands and 

commercial fields. The lure crops have also proven 

beneficial to many other bird and wildlife species.

Repellents, Propane Cannons, Pyrotechnics, and 

Farming Practices

NWRC researchers are working to identify, develop, 

and improve the use of chemical repellents for 

reducing blackbird damage to ripening sunflowers. 

However, before any repellent can be used effectively 

in large-scale applications, land managers need 

a more effective method to spray repellents onto 

sunflower heads, which hang nearly horizontal to 

almost perpendicular to the ground. Wildlife Services 

field specialists and scientists also continue helping 

growers use other management tools and methods to 

reduce blackbird damage, including propane cannons 

and pyrotechnics to scare birds away from fields 

and farming practices that encourage the removal of 

ripened sunflowers earlier in the season. Applying 

a desiccant (drying agent), such as glyphosate and 

saflufenacil herbicides, to sunflowers enables farmers 

to harvest earlier and avoid late-season damage from 

blackbirds as a result.

Cattail stands are thinned to make them less suitable 

for blackbirds.

Roughly 39 million red-winged 

blackbirds, 19 million common 

grackles, and 17 million yellowheaded blackbirds migrate through 

the Great Plains each fall.

NWRC scientists partner 

with experts from 

NDSU and the National 

Sunflower Association.