USGS Science⌕ Search
Home/Archive/USGS

USGS · 5223322

Mercury concentrations in feathers of wading birds from Florida

W. N. Beyer·M. Spalding·D. Morrison
View original source ↗Read source document ↗Export metadata ↓

Abstract

Primary or tail feathers were collected from 92 wading birds in Florida from Lake Okeechobee and wetlands farther south, from 1987 to 1990. Mean concentrations detected in feathers of nestlings were 2.0 ppm Hg in roseate spoonbills (Ajaia ajaja), 3.5 ppm Hg in great blue herons (Ardea herodias), 4.7 ppm Hg in great white herons (Ardea herodias occidentalis), and 7.1 ppm Hg in great egrets (Casmerodius albus). Concentrations in feathers of great white herons increased with the age of the bird, from 4.7 ppm Hg in nestlings, to 6.7 ppm Hg in juveniles, and 8.2 ppm Hg in adults. Mercury concentrations were greatest in species consuming large fish. Feathers collected from wood storks (Mycteria americana) contained an average of 3.3 ppm Hg. Mercury concentrations in feathers of wading birds from southern Florida were greater than those reported in feathers of wading birds from Asia. Both liver and feather Hg concentrations were known for 25 wading birds. The regression of liver (wet weight) Hg concentrations (Y) on feather Hg concentrations (X) was: log(Y) = 1.52 log(X) - 0.722. The correlation coefficient was 0.84. If reproductive disorders are expected when concentrations in feathers of adult birds average 9 ppm Hg, as might be inferred from a published laboratory study on mallards (Anas platyrhynchos), then Hg in southern Florida may be high enough to reduce productivity of wading bird populations. However, additional controlled studies are needed before a minimum toxic concentration in feathers can be designated with confidence.

Explore related subjects

AmbioArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

W. N. Beyer, M. Spalding, D. Morrison. 1997. Mercury concentrations in feathers of wading birds from Florida. https://pubs.usgs.gov/publication/5223322

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

KEEP EXPLORING

Related USGS reports

USGS2026

Wicked problems in practice: Responding to ecological transformation in wilderness

Congressionally designated wilderness offers the highest level of land protection in the USA, comparable to category 1b wilderness as defined by the International Union for Conservation of Nature, yet wilderness areas face impacts of climate change. Researchers and managers increasingly recognize the immense challenge of stewarding wilderness in a changing climate. Although responding to climate change is considered a wicked problem, this framing has not been applied to wilderness contexts. We move theory into practice by using wicked problem framing and four illustrative cases to explore how the resist–accept–direct (RAD) framework can help untangle the wicked problem of addressing unprecedented ecological transformation in wilderness. The RAD framework clarifies a range of response options including resisting transformation, accepting it, or directing it toward preferred new conditions. As climate change continues to challenge wilderness managers, the RAD framework can help assess trade-offs and preserve wilderness character into the twenty-first century.

Ambio↗
USGS2026

Resilience thinking for human-wildlife coexistence: Bridging dynamic systems, archetypes, and transformations

As human activities and wildlife increasingly overlap in the Anthropocene, conventional conservation paradigms focused on land-sparing are shifting toward strategies that support human–wildlife coexistence. However, achieving sustainable coexistence is often hindered by a limited understanding of the dynamic social–ecological processes that drive integrated human–wildlife systems. This Special Issue explores “resilience thinking” as a scientific framework to address these knowledge gaps. By bridging sustainability and wildlife sciences, we examine how concepts such as adaptive capacity, feedback loops, system archetypes, and tipping points can illuminate the conditions that facilitate stable coexistence or lead to persistent conflict. Through diverse global case studies ranging from carnivore management in Europe to primate interactions in Indonesia, contributions highlight how societal perceptions, governance, and co-adaptation shape system trajectories. Ultimately, we argue that fostering durable coexistence requires moving beyond incremental adaptation toward transformative governance that centers on equity, relationality, and proactive management.

Ambio↗
USGS2025

Bridging social and ecological science to create spatially-explicit models of human-caused mortality of carnivores

Research indicates that human-caused mortality (HCM) is a key factor limiting numerous large carnivore populations. However, efforts to represent HCM in spatially explicit models have generally been limited in scope—often relying on proxies, such as road or human density. Yet such efforts fail to distinguish different sources of HCM, which can arise from different antecedent processes. We offer a systems-based conceptual framework for understanding the antecedents of HCMs that is grounded in theory from the social and behavioral sciences. Specifically, we first explain how HCMs are usefully distinguished into four types (e.g., accidental, harvest, illicit, control actions), then discuss how these different types tend to be driven by different sets of psychological and sociopolitical processes. We contend that improvements in understanding the spatial variation in HCMs would rise from more explicit attention to the various antecedent processes that precede each mortality type.

Ambio↗