Radiocesium Dynamics in Herons Inhabiting a Contaminated Reservoir System

Abstract

The little blue heron (Florida caerulea) and the green heron (Butorides virescens) nest at a radionuclide-contaminated reservoir on the Savannah River Plant near Aiken, South Carolina. Green herons distributed their nests singly along the periphery of the reservoir but fed their nestlings exclusively upon amphibians collected from adjacent uncontaminated Carolina bays. Radiocesium burdens in green heron nestlings did not exceed 5pCilg wet wt. and 12 regurgitated food pellets averaged 0.2 pCi/g. Twelve pairs of little blue herons established a heronry upon a small island and fed their nestlings fish and amphibians foraged from within the differentially radionuclidecontaminated reservoir system. Nestlings within the same nest did not exhibit significant differences in body burdens, and the maximum radiocesium burden determined was 27.4 pci/g wet wt. Substantial differences were found between nestlings from different nests however. The radiocesium level of 43 regurgitated food pellets had a high correlation with observed levels in the nestlings, and variation in food contamination is believed to be the major contributor to the observed variation in the nestlings. The variable contamination of primary prey species was correlated with the differentially contaminated foraging sites and indicates that adult little blue herons tended to spatially partition the available foraging areas.

Wading bird use of established and newly created reactor cooling reservoirs at the Savannah River Site, near Aiken, South Carolina, USA

“…3). Although several species of wading birds, including Great Blue Herons, Little Blue Herons, and Green-backed Herons, are known to breed on SRS (Domby, 1976;Domby & McFarlane, 1978;I. L. Brisbin, unpubl.…”

Distribution of Long‐Lived Radionuclides in an Abandoned Reactor Cooling Reservoir

“…Waterfowl and other birds Mayer et al (1986) Aythya collaris (Ring-necked Duck) Domby et al (1977) Bucephala albeola (Bufflehead) Norris (1963) The largemouth bass population (-15 cm in length) was estimated in 1986 by mark-recapture. Over 600 individuals were captured by angling, marked, and released.…”

Distribution of sup 137 Cs, sup 90 Sr, sup 238 Pu, sup 239 Pu, sup 241 Am and sup 244 Cm in Pond B, Savannah River Site

“…Numerous species of aquatic birds are known to occur on the Savannah River Site (Norris, 1963) In addition to the waterfowl, several species of waders are found at Pond B, the most important being green-backed herons (Butorides virescens) and little blue herons (Florida caerulea) which may breed in small numbers along the pond margins and on the larger islands (Domby et al, 1977). Numerous common grackles (Quiscalus auiscula) and red-winged blackbirds (A~elaius Rhoeniceus) also nest in these same areas.…”