CIRCULAR 15. FISH AND WILDLIFE SERVICE 



populations was obtained by live- 

 trapping both before and after 

 spraying, and an intensive search 

 was made for mortalities. No 

 evidence was found that any of 

 the five species of small mammals 

 taken by trapping was measur- 

 ably reduced by any of the spray 

 applications. 



A systematic coverage of plots 

 also showed little effect on the 

 varied bird population. The small 



size of the plots, however, several 

 of which were also long and nar- 

 row, and the fact that few indi- 

 viduals were restricted to terri- 

 tories by nesting activities, un- 

 doubtedly minimized the effects of 

 the treatment. Arctic three-toed 

 woodpeckers in a nest near the 

 center of the plot that received the 

 application of 71^ pounds of DDT 

 to an acre were unaffected by the 

 spraying and developed normally. 



ORCHARD INSECT CONTROL 



ALLEGANY COUNTY, MD. 



A rather cursory survey of bird 

 populations in an orchard area in 

 Allegany County, Md., indicated 

 that DDT as used for codling 

 moth control may have pro- 

 nounced effects on the bird popu- 

 lations. Late in July, a bird cen- 

 sus was taken on a 22i/4-acre plot 

 in an orchard that had been 

 sprayed with DDT, and four 

 species were found present in the 

 ratio of 31 pairs to 100 acres. A 

 similar plot in a nearby orchard, 

 unsprayed because of early frost 

 damage, had a population of 89 

 pairs to 100 acres and represented 

 by nine species. 



The spray schedule followed in 

 the treated orchard called for the 

 deposition of an equivalent of 15 

 to 22.5 pounds of DDT to an acre 

 for each application. At the time 

 of the study two applications had 

 been made ; hence 30 to 45 pounds 

 of DDT to an acre had been dis- 

 tributed on the area. Additional 

 cover sprays brought the total 



quantity of DDT applied to the 

 orchard during the season to 60 

 to 70 pounds or more to an acre. 



ALBANY, GA. 



Between July 30 and August 28, 

 1947, Dr. Eugene P. Odum and 

 Robert A. Norris, collaborators of 

 the Fish and Wildlife Service, 

 conducted studies on the effect on 

 birds of DDT used in pecan weevil 

 control near Albany, Ga. Ten 

 pecan groves were under observa- 

 tion. Four of these received one 

 application of DDT, three re- 

 ceived two applications (about 2 

 weeks apart), and three un- 

 sprayed groves were used as check 

 areas. 



The spray formulation was 6 

 pounds of 50-percent wettable 

 DDT powder (3 pounds of DDT) 

 to each 100 gallons of water. The 

 quantities of the mixture applied 

 by individual owners contained 

 DDT in amounts ranging from 

 0.18 to 0.43 pound to a tree or 

 from 2.0 to 6.5 pounds to an acre 



