EFFECTS OF DDT AND OTHER INSECTICIDES 



(the average being 4.3 pounds to 

 an acre). The spray was con- 

 fined mostly to the trees and little 

 reached the ground level between 

 or under the trees. 



By the time spraying was be- 

 gun most birds had completed 

 nesting. Nevertheless, without 

 considering juvenile and transient 

 birds, a reasonably stable popula- 

 tion was worked with, the birds 

 numbering 50 to 104 individuals 

 to 100 acres in different orchards. 



Population counts indicated lit- 

 tle effect of the DDT spraying. A 

 decline in numbers of birds in 

 treated areas was noted, but this 

 was about comparable with the 

 decreases observed in check or- 

 chards. No dead birds or birds 

 showing symptoms of DDT poi- 

 soning were seen. Of four nests 

 under observation, both before 

 and after spraying, the birds in 

 three progressed normally but the 

 fourth nest was deserted after the 

 second spraying. The cause of 

 desertion could not be definitely 

 determined. 



For a day or more after the 

 spraying operations numerous 

 dead and dying insects, represent- 



ing many species, were conspicu- 

 ous on the sparsely covered 

 ground. With minor exceptions, 

 the birds were not attracted to 

 this ready source of food but con- 

 tinued to forage in their normal 

 niches. 



The dosages of DDT used in 

 pecan weevil control are known to 

 be critical for birds when used 

 under other conditions. Factors 

 that might mitigate the effects on 

 birds in the type of operation con- 

 ducted at Albany, Ga., would 

 probably include : (1) the limited 

 size of the orchards, the birds not 

 being confined to the treated area, 

 and their summer feeding range 

 extending beyond the orchard 

 limits; (2) the period of spraying 

 was later than the peak nesting 

 period, and only a few late-nest- 

 ing individuals were concerned 

 with the nearly continual job of 

 food-gathering required of birds 

 with nestling young; and (3) ex- 

 cept for a few ground-feeding 

 species, the birds appeared not to 

 be attracted to the abundant 

 ground supply of fallen, contami- 

 nated insects. 



