Organochlorine pollutants, eggshell thickness, and reproductive success of black-crowned night-herons in Idaho, 1979

Publication Type:

Journal Article

Authors:

Findholt, Scott L.; Trost, Charles H.

Source:

Colonial Waterbirds, The Waterbird Society, Volume 8, Issue 1, p.32-41 (1985)

Call Number:

A85FIN01IDUS

Keywords:

black-crowned night-heron, DDE, eggshell thinning, Idaho, nesting success., Nycticorax nycticorax, organochlorine compounds

Abstract:

In 1979, eggshell thickness of Black-crowned Night-Herons (Nycticorax nycticorax) nesting in southeastern Idaho was significantly lower than that of pre-1947 eggs. Shell thickness was negatively correlated with DDE and DDD concentrations (log-transformed) in egg contents. The highest correlation was between shell thickness and DDE concentration. Mean clutch sizes in two of three colonies were significantly smaller than pre-1947 mean clutch sizes from Utah. Predation and DDE-induced losses were major factors contributing to egg destruction, and starvation probably accounted for most nestling mortality. Hatching success, percent of successful nests, number of chicks per successful nest, and shell thickness decreased, while number of eggs that disappeared or broke increased at high concentrations of DDE. Nesting success in 1979 appeared too low to sustain current population levels. Band-recovery data, high incidence of DDT in sample eggs, and total DDT:PCB ratios suggest that night-herons probably are being contaminated with DDT-DDE on wintering grounds in the southwestern United States and Mexico.

Notes:

Reference Code: A85FIN01IDUS

Full Citation: Findholt, S. L., and C. H. Trost. 1985. Organochlorine pollutants, eggshell thickness, and reproductive success of black-crowned night-herons in Idaho, 1979. Colonial Waterbirds 8(1): 32-41.

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