Blackbird catch in decoy trap being driven into gather- 

 ing cage in upper corner of trap so that they can be 

 caught for banding or other research. (Photo by 

 John T. Linehan) 



Research biologist banding blackbirds in decoy trap 

 during late summer depredations period at Newark, 

 Del. Over 20.000 blackbirds were captured in this 

 trap during a 35-week interval. (Photo by John T. 

 Linehan) 



140 pliytotolei'iince tests, 52 toxicity determina- 

 tions, and 5 translocation studies. In addition, 104 

 secondary bioassays, 79 toxicity determinations, 

 92 phytotolerance tests, and 12 translocation stud- 

 ies were made with compounds examined earlier. 

 As a result of continued screening, it is anticipated 

 that as many as 10 new compounds may be sent to 

 the Olympia field station for further trials during 

 the coming year. 



On the basis of experience gained in the past 2 

 years, it has been possible to reduce the initial 

 screening bioassay from 100 to 15 animal-days 

 without loss of reliability. This change will 

 make it possible to devote more time to develop- 

 mental research with promising chemicals. 



Protection for packaged goods. — Sixteen years 

 of research in cooperation with the U.S. Quarter- 

 master Eesearcli and Development Command has 

 resulted in tlie appraisal of approximately 8,500 

 candidate cliemicals as rodent repellents for use 

 on packaging materials. Such factors as toxicity, 

 handling hazard, cost, and migration of the chem- 

 ical into packaged contents have been enough to 

 eliminate all tlie active repellents so far discovered. 

 Research has now evolved to a polyethylene-tex- 

 tile-polyethylene multiwall cover or tarp, with 

 only the middle layer being treated with a highly 

 active rodent repellent. Tlie multiwall tai'p will 



be used as a cover for stacked packaged goods and 

 will greatly reduce handling and contamination 

 hazards. 



Nittria control. — From numerous releases, both 

 intentional and accidental, nutria have become 

 established in many sections of the United States. 

 As so often happens with introduced species, these 

 animals are conflicting with man's interests in 

 many ways. The problem is particularly acute 

 in the coastal regions of Louisiana and Texas, 

 where nutria are causing serious damage to water 

 structures and to such agricultural crops as sugar- 

 cane and rice. 



xVs a result of congressional action, $50,000 was 

 made available during fiscal year 1963 for re- 

 search on methods of controlling nutria damage, 

 and a similar amount was appropriated for direct 

 control purposes. A Nutria Research Station has 

 been established at Houma, La., which will serve 

 as headquarters for field and laboratory studies 

 on methods of alleviating property and crojj losses 

 to these rodents. A smaller station was estab- 

 lished at Beaumont, Tex., for study of the prolilem 

 as it exists in that area. 



Reproduction inliihitorx for controlling coy- 

 otes. — One phase of the study of reproductive in- 

 hibitors as a means of coyote control was com- 

 pleted in tlie spring of 19G2 when experiments 



43 



