Code

CCBTR-08-08

Publication Date

2008

Abstract

Bald Eagles were monitored at Naval Support Facility Indian Head, Maryland in compliance with a 2007 Biological Opinion prepared by the US Fish and Wildlife Service. Eagle nests were surveyed for breeding activity and productivity using a standard 2‐flight protocol. A Cessna 172 aircraft was used to systematically survey the property to locate eagle nests and determine nesting activity. Nests were climbed with arborist equipment or accessed with a bucket truck. Eagle nestlings were banded and measured. Blood and feather samples were collected from 18 nestlings to test for Encephalitis viruses and mercury and organochloride contaminants. One addled egg was collected for contaminant testing. Nine nests were active during the 2008 breeding season. Productivity rates were estimated at 2.0 chicks/active nest (nest observed with eggs or chicks) and 2.25 chicks/productive nest (chicks reached fledging age). All nestlings tested negative for encephalitis viruses including West Nile Virus. Mercury levels were subacute in blood ( x = 0.05 mg/kg) and feathers ( x =1.22 mg/kg). The single addled egg had a mercury value of 0.09 mg/kg. Contaminant levels in blood were also subacute for total PCBs ( x = 0.044 μg/g), total Chlordane ( x = 0.010 μg/g), and DDE ( x = 0.013 μg/g). Values for the addled egg approached toxicity thresholds for PCBs and DDE. Productivity rates were not significantly higher at Indian Head than at nearby Virginia nests along the Potomac River. Forty‐four percent fledged 3 chick broods indicating high prey‐availability on the Upper Potomac and on Mattawoman Creek. All contaminant levels were low in nestling blood and feathers. High levels of PCB and DDE contaminants likely contributed to reproductive failure at the Extrusion nest but results are inconclusive. High levels of these contaminants are present in nearby foraging areas along the Potomac River with point and non‐point source contamination documented upstream of NSF Indian Head.

Topic

Abundance/distribution; Breeding/Demography/Pop Dynamics

Species

Bald Eagle

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