Residues of DDT in brains and bodies of birds that died on dosage and in survivors.

Residues of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane (DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethane (DDD) in brains of cowbirds (Molothrus ater) killed by dietary dosage of DDT were similar in birds that died after various lengths of time on dosage and in birds that died of delayed effects after as much as 40 days on clean food. Residues of DDT and DDD, but not of 1,1-dichloro-2,2-bis-(p-chlorophenyl)-ethylene (DDE), were much lower in survivors 112 days after dosage. The relative importance of DDT and DDD in brains could not be determined, but DDE appeared not to be critical. Residues in brains of cowbirds were similar to those reported for robins, sparrows, eagles, and white rats. Residues in livers and carcass remainders (with the possible exception of DDD in the liver) appeared unsuitable for diagnosing the cause of death.