Wintering area DDE source to migratory white-faced ibis revealed by satellite telemetry and prey sampling

By: , and 



Locations of contaminant exposure for nesting migratory species are difficult to fully understand because of possible additional sources encountered during migration or on the wintering grounds. A portion of the migratory white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada continues to be exposed to dichloro-diphenyldichloro-ethylene (DDE) with no change, which is unusual, observed in egg concentrations between 1985 and 2000. About 45-63% of the earliest nesting segment shows reduced reproductive success correlated with elevated egg concentrations of >4 ??g/g wet weight (ww). Local prey (primarily earthworms) near nests contained little DDE so we tracked the migration and wintering movements of 20 adult males during 2000-2004 to determine the possible source. At various wintering sites, we found a correlation (r 2 = 0.518, P = 0.0125, N = 11) between DDE in earthworm composites and DDE in blood plasma of white-faced ibis wintering there, although the plasma was collected on their breeding grounds soon after arrival. The main source of DDE was wintering areas in the Mexicali Valley of Baja California Norte, Mexico, and probably the adjacent Imperial Valley, California, USA. This unusual continuing DDE problem for white-faced ibis is associated with: the long-term persistence in soil of DDE; the earthworms' ability to bioconcentrate DDE from soil; the proclivity of white-faced ibis to feed on earthworms in agricultural fields; the species's extreme sensitivity to DDE in their eggs; and perhaps its life history strategy of being a "capital breeder". We suggest surveying and sampling white-faced ibis eggs at nesting colonies, especially at Carson Lake, to monitor the continuing influence of DDE.

Publication type Article
Publication Subtype Journal Article
Title Wintering area DDE source to migratory white-faced ibis revealed by satellite telemetry and prey sampling
Series title Ecotoxicology
DOI 10.1007/s10646-009-0400-8
Volume 19
Issue 1
Year Published 2010
Language English
Contributing office(s) Forest and Rangeland Ecosystem Science Center, Contaminant Biology Program
Description 10 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecotoxicology
First page 153
Last page 162
Google Analytic Metrics Metrics page
Additional publication details