"Plying mousetraps" — by day and night (left, red-shouldered hawk; right, barn owl). Several Cooperative Wildlife 

 Research Unit and other Bureau research projects have dealt with predator-prey relations. Mice are a mainstay in 

 the food of most hawks and owls. (Photos by L. G. Kesteloo) 



ANIMAL CONTROL METHODS 



The problems of animal damage become more 

 acute as competition between man and wild ani- 

 mals increases, tints compounding the need for 

 more selective and effective control measures for 

 birds and mammals injurious to forests, crops, or 

 rangelands, to stored goods, or otherwise inimical 

 to human welfare or health. Many approaches 

 to the control of such animals are being explored, 

 including manipulation of habitat, cultural prac- 

 tices, chemical repellents and scaring devices, 

 drugs and lethal substances, traps, sonic and elec- 

 tronic installations radiation, reproductive in- 

 hibitors, and bacteriological agents. 



Physiology in bird control. — Physiological 

 studies undertaken at the Denver Center will 

 facilitate the development of safe and effective 

 methods for controlling damage by starlings and 

 blackbirds. An important phase of this work in- 

 volved telemetering and recording of physiologi- 

 cal characteristics such as circulation, heart rate, 

 brain waves, body temperature, and respiration 



rate via sensors and transducers surgically im- 

 planted in birds. Such systems permit continuous 

 recording of physiological data from birds l>eing 

 restrained only by cages. Information obtained 

 in this manner will be valuable in determining the 

 physiological basis of chemical repellency and 

 toxicity, and for evaluating the effectiveness of 

 mechanical and chemical control measures. 



New ovicide for starlings and blackbirds. — The, 

 new candidate avicide, DRC-1339, has survived a 

 series of laboratory and field tests with excellent 

 results and has shown much promise as a slow- 

 acting oral toxicant. The material is 300 to 500 

 times as toxic to starlings as to rats, suggesting a 

 wide margin of safety for mammals. The chem- 

 ical is readily accepted by starlings with fatalities 

 occurring 6 hours to 5 days later. In initial field 

 trials more than 100 starlings have been killed per 

 pound of bait exposed. Research is near comple- 

 tion on this compound, and efforts will be directed 

 toward registration, release, and availability for 

 use during 1964. 



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