Contaminants in wood stork eggs and their effects on reproduction, Florida, 1982

W. James Fleming; J.A. Rodgers; C. J. Stafford

doi:10.2307/1521086

Home/Archive/USGS

USGS · 5221969

Contaminants in wood stork eggs and their effects on reproduction, Florida, 1982

W. James Fleming·J.A. Rodgers·C. J. Stafford

View original source ↗Export metadata ↓

Abstract

One egg was removed from five Wood Stork (Mycteria americana) nests at each of eight colonies in central and northern Florida in 1982. DDE and mercury were present in all eggs with concentrations ranging up to 9.4 and 0.73 ppm wet weight, respectively. PCBs were detected in 25 eggs (63%) with a high value of 3.5 ppm. Other organochlorine compounds occurred in less than 30% of the eggs. Contaminant concentrations were remarkably similar among colonies. Overall, DDE and PCB concentrations were significantly less (P < 0.05) in Wood Stork eggs collected in Florida in 1982 vs. those collected in 1973. DDE was negatively correlated with eggshell thickness (r = -0.48 P <.0.01). Eggshell thickness was greater in 1982 than it was during the period 1967-73 (P.< 0.09) but was still 4.3% less than in eggs collected before 1947 (P < 0.05). Eggs from nests with less than 100% hatching success were linked with higher DDE concentrations (2.92 ppm vs 1.01; P = 0.09), but contaminants showed no significant link to fledging success. Although it is possible that a few individuals may have been affected by DDE, we found no evidence that organochlorine pesticides, PCBs, or mercury were significantly depressing Wood Stork populations.

Explore related subjects

Colonial Waterbirds Article

Source-reported bounding extent: 24.546468° to 31.000682° latitude; -87.634938° to -80.031362° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

W. James Fleming, J.A. Rodgers, C. J. Stafford. 1984. Contaminants in wood stork eggs and their effects on reproduction, Florida, 1982. https://doi.org/10.2307/1521086

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS1998

Status of the white-faced ibis: Breeding colony dynamics of the Great Basin population, 1985-1997

The status of the White-faced Ibis (Plegadis chihi) in the Great Basin is of concern because of its small population size and the limited and dynamic nature of its breeding habitat. We analyzed existing annual survey data for the White-faced Ibis breeding in the Great Basin and surrounding area for 1985-1997. Methods varied among colonies and included flight-line counts and fixed-wing aircraft and helicopter surveys. The number of White-faced Ibis breeding pairs in the Great Basin area has nearly tripled since 1985, despite years of severe flooding and drought at major breeding areas. This growth is reflected in both peripheral (i.e., Oregon, California, Idaho) and core (i.e., Nevada and Utah) components of the population. Our data on colony dynamics in Oregon and Nevada illustrate the ability of the highly nomadic White-faced Ibis to compensate for poor conditions at traditional colony sites by moving among colonies and rapidly colonizing newly available wetlands. We suggest that the White-faced Ibis would benefit from a landscape mosaic of well-distributed peripheral wetlands and persistent colony sites. The nomadic nature of the White-faced Ibis and the dynamic nature of their breeding habitat necessitates that wetland management decisions and population monitoring be conducted in a regional context.

Colonial Waterbirds↗

USGS1998

Diets of nestling gull-billed terns in coastal Virginia

We studied the diets of nestling Gull-billed Terns (Sterna nilotica) at colonies in coastal Virginia during the breeding seasons of 1995 and 1996 as part of a long-term study of the species. No previous quantitative assessments had been made of diets of this species anywhere along the Atlantic Coast, and only a few observations had been reported from other coastal areas in the southern United States. During 80 h of observations over the two seasons, 757 feeding observations were made, primarily at two colony sites. We examined how prey type (fish, marine invertebrates, terrestrial prey) and size were influenced by year, tide cycle, season (early and late) and age of the young (small chicks < 7 d old versus large chicks > 7 d). We did not find significant year differences, but all other factors revealed statistically significant results. Older (>7 d) chicks were fed relatively more terrestrial and marine invertebrate prey than were younger chicks. In June (early season), fewer fish and terrestrial prey were fed to chicks than later (July-August). Most prey were less than one bill length in size, with the majority of the smallest prey being marine invertebrates. Tide cycle influenced prey delivered with terrestrial prey becoming relatively more important during high and ebb periods than during low and flood tides when aquatic prey dominated. The major marine invertebrate prey taken was the fiddler crab (Uca spp.). Terrestrial prey consisted mostly of large odonates and orthopterans. Unlike earlier reports from Europe, we found no regurgitated food pellets in any of the colonies in either year. This study confirms that the Gull-billed Tern is an extremely opportunistic feeder and has adapted to a variety of habitats, helping to explain its cosmopolitan distribution.

Virginia↗

USGS1998

Key areas for wintering North American herons

Nearly all North American heron populations are migratory, but details of where they winter are little known. Locations where North American herons winter were identified using banding recovery data. North American herons winter from Canada through northern South America but especially in eastern North America south of New York, Florida, California, Louisiana, Texas, Mexico and Cuba, these areas accounting for 63% of winter recoveries. We identified regions where recoveries for various species clustered as 'key areas.' These forty-three areas constitute a network of areas that hold sites that likely are important to wintering herons. The relative importance of each area and site within the network must be evaluated by further on the ground inventory. Because of biases inherent in the available data, these hypothesized key areas are indicative rather than exhaustive. As a first cut, this network of areas can serve to inform further inventory activities and can provide an initial basis to begin planning for the year-round conservation of North American heron populations.

Colonial Waterbirds↗