Large decoy traps for bhu-kbirds were tested on 

 a 100-square-niile area of sweet and field corn in 

 New Castle County, Del., during the corn-depre- 

 dation period. Of 37,000 birds captured in about 

 50 days, cowbirds made up 62 percent, common 

 grackles 13 percent, starlings 13 percent, and red- 

 winged blackbirds 12 percent. Redwings were the 

 principal target species. 



The effectiveness of large and small decoy traps 

 was compared in a cherry-blueberry depredations 

 area in Berrien County, Mich. Small (6 by 8 

 foot ) traps and conventional large ( 16 by 48 foot) 

 enclosures were operated in pairs on 10 cherry or 

 blueberry fanns. Of 32,000 birds taken, -46 per- 

 cent were starlings, 27 percent were cowbirds, 16 

 percent were common grackles, 8 percent were red- 

 winged blackbirds, and 3 percent were house spar- 

 rows. Eighty percent of the catch was taken in 

 the large traps, and included 75 percent of the 

 starlings, 82 percent of the grackles, 87 percent of 



the cowbirds, and 95 percent of the redwings. 



Tlie tentative conclusion is that, while decoy 

 traps are effective under some conditions, they do 

 not hold high promise for effective control of 

 blackbirds over large areas. 



Color marking pays of in blackbird handing. — 

 Results from marking more than 26,000 blackbirds 

 and starlings by the Denver Center with colored 

 1- by 4-inch Facilon plastic strips have shown that 

 colored tags significantly improve returns of 

 banded birds. When valid sight records from 

 color-tagged birds were added to actual recover- 

 ies, the return rate of redwings was 3.5 times 

 greater, and for .starlings it was 2 times greater. 

 Questionnaire replies from 87 persons recovering 

 tagged birds supplied the reason for the increase: 

 birds collected because of tag, involving 62 percent 

 of the blackbirds and 82 percent of the starlings. 

 The technique is proving to be of much value in 

 tracing dispersal of birds and from banding sites. 



Along witi trapping, frightening devices, and chemicals, the Bureau is exi)erimenting with biological mean.s of nuisance- 

 animal control. In a lU&l test with predators, two raccoons and two foxes released on Ram Island practically 

 eliminated gull production. Similar results were attained with raccoons and foxes on another experimental island. 

 (Photo by John A. Kadlec) 



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