t'anada geis, m .'.( /' feeding test.— The feed- 

 ing habits of Canada geese make them vulnerable 

 to herbicide ingestion. To investigate the impacl 

 nf one such material on the internal organs of 

 geese, an ad-lib feeding tesl using 1,000 p.p.m. of 

 2,4-D sodium salt was initiated at the Denver Cen- 

 ter. Upon examination, tissue damage in the form 

 of progressive kidney enlargement and a general 

 "jaundiced" appearance of the viscera was evident. 

 Microscopic examination of tissues indicated more 

 specific damage consisting in general "disorgani- 

 zation" of the kidney and liver cellular structures 

 through a fatty degeneration, round-cell and con- 

 nective-tissue invasion, lesions and dissolution of 

 renal tubules, arteriole wall enlargement, and 

 glomeruli enlargement . 



Histologic examination of geese removed from 

 extended treatment and placed on a "clean" con- 

 trol diet indicated that tissue damage may be 

 repaired. 



Sevin appears loir in toxicity to wildlife. — At 

 Lost wood National Wildlife Refuge in North 



Dakota, Sevin, an insecticide of the carbamate 

 group, is being field tested by the Denver Center 

 for acute and chronic effects on wildlife. In the 

 laboratory, this compound appears to be of low 

 toxicity to birds and mammals and is not stable in 

 composition, thereby reducing chronic hazard in 

 the field. It appears promising for use on upland 

 areas where pests such as grasshoppers must be 

 ■ Hiit rolled with minimal danger to wildlife. 

 Spraying of water areas should be avoided be- 

 cause of its high toxicity to some forms of aquatic 

 life. 



Pesticides and prairie grouse. — Tests with 

 penned prairie grouse have indicated that dieldrin 

 is highly toxic to them. The largest oral dose 

 survived by sharptails has been 1.5 mg kg. and by 

 prairie chickens, 10 mg/kg. Sevin, a carbamate 

 insecticide of potential use on grouse range, has 



Holding pen with water and feeder used in conducting pesticide studies with wild ducks and Reese. Denver Wildlife 

 Research Center. ( 1'hoto hy M. (!. Sheldon) 



44 



