APHIS Stakeholders Announcement

Wildlife Services July 2012

USDA Investigates 

How Ultraviolet Cues 

Infl uence Blackbird 

Feeding Behavior:

Research May Lead 

to More Effective 

Bird Repellents

Researchers with the U.S. Department of Agriculture’s 

(USDA) Animal and Plant Health Inspection Service 

(APHIS) recently investigated the role of ultraviolet 

(UV) cues in avian food selection. Although it has 

long been known that birds use UV wavelengths for 

mate selection, researchers have now learned that UV 

wavelengths also infl uence bird feeding behavior and 

food selection. While UV wavelengths are invisible to 

humans, APHIS researchers found that birds exposed 

to an UV-absorbent, post-ingestive repellent subsequently avoided UV-absorbent and UV-refl ective food. 

The researchers hope to use these fi ndings to improve 

our understanding and management of bird damage to 

agriculture. These studies are summarized in a recent 

article titled “The role of a generalized ultraviolet cue 

for blackbird food selection” in Physiology & Behavior

(vol. 106, 597–601). 

Taste, smell, and sight help birds and mammals identify and discriminate among foods, but these senses 

play somewhat different roles in food preference and 

food selection. In studies with captive red-winged 

blackbirds, researchers at the USDA-APHIS National 

Wildlife Research Center (NWRC) learned that blackbirds shift preferences for both familiar and unfamiliar 

fl avors based on their feeding experiences and rely on 

visual cues to avoid food previously paired with negative 

consequences. 

“From our feeding experiments, we learned that blackbirds associate pre- and post-ingestive consequences 

with visual cues, and they integrate their visual and 

fl avor experiences with post-ingestive consequences 

to select nutrients and avoid toxins,” states Dr. Scott 

Werner, research wildlife biologist at the NWRC. “For 

example, blackbirds avoided the color and fl avor of food 

previously paired with a post-ingestive repellent. In 

contrast, birds avoided only the color (not the fl avor) 

of food previously paired with methyl anthranilate (a 

pre-ingestive irritant). These fundamental relationships are helping us develop effective bird repellents 

for agricultural production.”

Several chemical repellents and cues that either 

absorb or refl ect UV wavelengths might be integrated 

in a management strategy that involves an initial 

application of a repellent and subsequent application 

of a visual cue with spectral characteristics similar to 

the repellent. NWRC researchers plan to investigate 

the use of UV feeding cues by other bird species 

and identify the UV wavelengths of agricultural crops 

associated with bird depredations.

The NWRC is the research arm of APHIS’ Wildlife 

Services program, which is devoted to resolving 

human-wildlife confl icts. The Center applies scientifi c 

expertise to develop practical methods to resolve 

these confl icts and maintain the quality of environments shared with wildlife. To learn more about the 

NWRC, visit its Web site at www.aphis.usda.gov/

wildlife_damage/nwrc/.

Note to Stakeholders: Stakeholders announcements 

and other APHIS information are available on the 

Internet. Go to the APHIS homepage at www.aphis.

usda.gov and click on the “Newsroom” button. For 

additional information on this topic, contact Gail Keirn 

at (970) 266-6007 or gail.m.keirn@aphis.usda.gov.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture

USDA is an equal opportunity provider and employer.