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Some rice growers report 100-percent losses due to bird depredation. 



TITLE: Development of Repellants and Other 

 Techniques for Managing Blackbird 

 Depredations to Rice 



GOAL: Develop a blackbird repellant for rice, 



improve the effectiveness of DRC-1339 for 

 managing blackbird populations, determine 

 local and regional movement patterns of 

 blackbirds, and develop new or improved 

 management strategies for reducing 

 blackbird damage to rice. 



Red-winged blackbirds, common grackles, and 

 brown-headed cowbirds cause an estimated $11.5 

 million worth of damage to newly planted and 

 ripening rice in Arkansas, California, Louisiana, 

 Missouri, and Texas every year. Some individual 

 growers report 100-percent losses due to bird 

 depredation. NWRC scientists routinely work 

 with rice producers, rice commodity groups, rice 

 research boards, universities, and local, State, 

 and Federal agencies to develop safer and more 

 effective methods to reduce bird depredation on 

 seeded and ripening rice and improve profitability 

 for growers. 



To develop new methods and tools. Center scientists 

 conduct multifaceted research studies involving 

 the use of both captive and free-ranging birds. 



These studies will determine the status of blackbird 

 populations in the southern rice-growing States, 

 estimate the economic impacts of birds on the rice 

 crop, evaluate and develop nonlethal repellants 

 for deterhng birds, and improve the effectiveness 

 and safety of avicides for reducing depredating 

 populations. 



Potential Blackbird Repellants for Rice — Tests 

 were conducted at the NWRC outdoor animal facility 

 in Fort Collins, CO, to identify potential nonlethal 

 repellants for reducing bird depredation on newly 

 planted rice seed and ripening rice. Based on 

 a series of feeding trials with captive red-winged 

 blackbirds, Tilt® and caffeine were identified as two 

 promising repellants. 



NWRC scientists, in cooperation with researchers 

 at the University of Missouri Delta Center, 

 Southeast Missouri State University, and Missouri 

 WS, conducted controlled tests in large netted 

 enclosures to evaluate the effectiveness of Tilt and 

 caffeine as repellants for red-winged blackbirds in 

 ripening rice fields. During these field trials, Tilt did 

 not result in any differences in damage between 

 the treated and untreated plots, probably because 

 chemical residues of the repellant were far below 

 the repellancy threshold. For caffeine, damage 

 was slightly less (although not at statistically 



12 Developing Methods 



