CIRCULAR 15, FISH AND WILDLIFE SERVICE 



In another of the areas receiv- 

 ing a dosage of 5 pounds of DDT 

 to an acre, Dr. Clarence Hoffman, 

 of the Bureau of Entomology and 

 Plant Quarantine, noted a shrew 

 in a condition of extreme excita- 

 bility. It died a few minutes 

 after it was observed. Although 

 it was not definitely established 

 that the shrew died as a result of 

 DDT poisoning, the symptoms 

 were highly suggestive. 



Birds 



Observations were made on 

 birds from July 19 to August 4. 

 Since nesting by most species was 

 completed at that time, a census 

 could not be obtained. A record, 

 however, was kept of individuals 

 seen while the investigator was 

 traversing marked paths through 

 the study plots, and this modified 

 "strip-count" provided a rough 

 index to numbers and species in 

 the areas both before and after 

 spraying. There was consider- 

 able movement of birds in the 

 study areas. Each of the treated 

 blocks, however, was an isolated 

 unit, all of which was completely 

 treated, so that the birds in a 

 given unit were subjected to the 

 same conditions of spraying. In 

 all, 33 species were under obser- 

 vation. 



In the area that received 714 

 pounds of DDT to an acre, the 

 average daily number of birds 

 seen prior to spraying was 69. 

 After the first application of 

 spray (S%, pounds to an acre) 

 the same working procedure re- 

 sulted in a count of 51 birds, a 



decline of 26 percent. After the 

 second treatment the average 

 daily count dropped to 21 birds, a 

 decline from the prespray counts 

 of 69.5 percent. 



In the area treated with 5 

 pounds of DDT to an acre a 42- 

 percent increase in counts of birds 

 occurred after the first applica- 

 tion, and after the second spray- 

 ing 22 percent more sight records 

 were recorded than in the period 

 before treatment. Counts taken 

 in a check area showed marked 

 increases during the same period. 



As was to be expected, the 

 greatest numbers of dead and dy- 

 ing birds were found in the area 

 that received 71/2 pounds of DDT 

 to an acre. Of the five victims 

 found in this unit, three were 

 pink-sided j uncos. Five species 

 of woodpeckers were not observed 

 to be aff'ected by the heavy dosage, 

 and two families of grouse, one 

 with five young and the other with 

 three, survived the 5-pound treat- 

 ment. 



Although the population studies 

 were inadequate to determine the 

 true effects, the complete absence 

 of some species following treat- 

 ment and the numbers of affected 

 individuals seen were indicative 

 of substantial kills in both the 

 area treated with the 5-pound 

 dosage and the one treated with 

 the 7l^-pound dosage. 



Fishes 



Three of the four plots selected 

 for treatment were so situated 

 that aquatic life was little af- 

 fected. The fourth plot was bor- 



