Housing for birds used in pesticide studies at the Patuxent Center. Cages are used for eagles, gulls, sparrow hawks, 

 blackbirds, and cowbirds. The structures are comfortable, can be maintained in sanitary condition, and are 

 suitable for long-term care of birds required for experimental purposes. (Photo by Frederick C. Schmid) 



DDT contamination, with residues totaling 384 

 ppm in the air-dried composite sample taken im- 

 mediately after DDT ajjplication. Three months 

 later, samples from the same sites carried residues 

 of 211 ppm. In air-dried balsam-root {Balsa- 

 rnorhiza sagiftata), 312 ppm were found immedi- 

 ately after spraying and 149 ppm were present 

 3 months later. Big sagebrush {Artemesia tri- 

 dentata), sunilarly collected and treated, carried 

 148 ppm immediately after the .spray application 

 and 59 ppm 3 months later. Air-dried Douglas- 

 fir {PsuedotHuga taj-ifoUa) samples contained 79 

 ppm of DDT 3 months later, plus metabolites. 

 Samples of these species from unspraj'ed check 

 areas carried no detectable DDT residues. 



The total DDT residue found in samples of 

 dried rumen contents from five deer collected on 



the area a month after spraying were 156, 185, 27, 

 76, and 152 ppm, whereas samples from four deer 

 collected in the same locality before spraying con- 

 tained no dete^^'t able residue. 



The main objective of the vegetative aspects of 

 the residue study was to gain a knowledge of tiie 

 amount and jjersistence of DDT spray contamma- 

 tion in forage plants used by deer tuid livestock. 



Death related to DDT I'esidit-eH in the brain. — 

 Whetiier bird deaths m the wild are due to pesti- 

 cides is often difficult to e.stablish because neither 

 dosage nor time of exposure may be known. To 

 be diagnostic of deatii, ivsidue levels nmst be sim- 

 ilar regardless of the time or dosage level. These 

 criteria have been met by scientists who have 

 studied brain residues found in experimental spar- 

 rows and bald eagles, and correlative evidence has 



49 



