BROWN PELICAN 



(Eastern subspecies— Pelc caims 



occidcntalis carolinensis Gmelin) 



(California s\ihspec\es—Pclcc anus 



occidcntalis californicus Rigdway) 



KINGDOM Animalia 



CLASS Aves 



ORDER Pelecaniformes 



FAMILY Pelecanidae 



OTHER COMMON NAMES 



Eastern subspecies Eastern brown pelican 



California subspecies . . . California brown pelican 



DATE 



Entered into SWIS to be determined 



Updates 



LEGAL STATUS 



Federal: Endangered: (35 FR 16047, 13 October 

 1970:35 FR 18319, 2 December 1970). 



States: Endangered: Georgia, Mississippi, 

 South Carolina, California. 

 Threatened: Florida. 



REASONS FOR CURRENT STATUS 



Both the eastern and California subspecies 

 have been greatly reduced in numbers. The main 

 reason for their decline is accumulation of chlorin- 

 ated hydrocarbon residues, which have been 

 shown to cause eggshell thinning and subsequent 

 crushing of eggs under the weight of parent birds 

 (Heath et al. 1969, Peakall 1970, Wiemer and 

 Porter 1970). The principal residues involved are 

 DDT compounds (DDE, DDD, and DDT), poly- 

 chlorinated biphenyls (PCB's),dieldrin,andendrin 

 (Schreiber and Risebrough 1972, BIus et al. 

 1974a). The correlation between eggshell thinning 

 and DDE concentrations is highly significant 

 (Schreiber and Risebrough 1972, Blus et al. 1975). 

 Blus et al. (1974b) demonstrated that the success 

 of 93 brown pelican nests was related to low levels 

 of DDE and dieldrin. 



Other factors affecting pelican populations 

 are availability of food supply and human distur- 

 bance of nesting colonies. Parent pelicans flushed 

 from nests exert forces large enough to break 

 eggs. Normally, one of the parents remains on the 



