Migratory Birds

The Golden-winged Warbler ( Vermivora chrysoptera), a small chickadee-like bird with a distinctive golden-colored cap and wing bars, is a species of considerable conservation concern in North America, primarily due to widespread population declines attributable to habitat loss and hybridization with the Blue-winged Warbler ( V. cyanoptera) in areas of sympatry. Recent concerns extend to the...

Aerial ocular surveys used by the United States Fish and Wildlife Service provide the most cost and time-efficient method to evaluate the relative abundance and spatial distributions of breeding, staging, and wintering waterbirds. However, the survey method is subject to substantial visibility bias, and visibility correction factors must be calculated to correct for incomplete detection...

During the breeding season (late March to early September), common loons can be found in the northern United States, and portions of Alaska and Canada. Common loons nest in lakes that range in size from 12 acres to over 10,000 acres. Nests are generally found near shore in a protected bay or in the lee of islands. Common loons prefer to nest on clear lakes with abundant small fish and are...

Amendments to the Clean Water Act in 1972 established federal jurisdiction over “navigable waters,” defined in the Act as the “waters of the United States.” A revised definition of the Waters of the U.S. rule took effect on 20 March 2023. However, various legal challenges precluded implementation of the new definition. On 25 May 2023, the U.S. Supreme Court, in the case of Sackett et ux. v...

Along the Santa Clara River in California, populations of the federally and state-listed Least Bell's Vireo ( Vireo bellii pusillus) are recovering from near extirpation. Habitat protection and restoration, as well as reducing brood parasitism by Brown-headed Cowbirds ( Molothrus ater), are thought to be the primary drivers of this recovery. The challenge going forward is to find the right balance...

Common loons often migrate several hundred miles to reach coastal waters during fall migration. Information about this part of the loon's life history is not well known. The use of satellite telemetry allows biologists to track loon movements through distant migrations and during winter. A transmitter attached to a radiomarked loon periodically sends a signal which is detected by a satellite-based...

The President's 2010 Budget provided $475 million for a new interagency Great Lakes restoration initiative, which targets the most significant problems in the region, including invasive aquatic species (like zebra and quagga mussels), non-point source pollution, and contaminated sediment. This initiative uses outcome-oriented performance goals and measures to target the most significant problems...

The Upper Mississippi River System (UMRS) is an important stopover point for waterfowl during early-spring and late-fall migrations, particularly portions of the river between the Navigation Pools 4 and 13.This part of the Upper Mississippi River contains large areas of aquatic vegetation that include preferred food sources such as Arrowhead and Wild Celery. In addition, many of these areas are...

The Upper Midwest Environmental Sciences Center (UMESC) in La Crosse, Wisconsin is studying the distribution and foraging patterns of sentinel fish-eating waterbirds through aerial surveys, and by tracking migration movements coupled with foraging depth profiles of common loons equipped with archival geo-locator tags and satellite transmitters. The results of this work are expected to elucidate...

Disturbance to resting and feeding waterfowl on the Upper Mississippi River National Wildlife and Fish Refuge (Refuge) is of utmost concern to refuge managers. Voluntary Waterfowl Avoidance Areas (VWAA) have been established to reduce boating disturbance to migratory waterfowl on Navigation Pools 7 and 8 of the Upper Mississippi River. Ongoing boater compliance with the VWAA programs has been...

The Golden-winged Warbler (Vermivora chrysoptera) is a species of considerable conservation concern in North America, primarily due to widespread population declines attributable to habitat loss (Confer et al. 1992, Buehler et al. ) and displacement by the Blue-winged Warbler (V. pinus) in areas of sympatry (Gill 1980, 2004; Will 1986). Recent research highlighted an important mechanism in the...

Climate change models predict warmer temperatures, changes to precipitation patterns, and increased evapotranspiration in the Great Lakes region. Such climatic changes have altered, and are expected to further alter hydrological, chemical, and physical properties of inland lakes. Lake-dependent wildlife are often sensitive to changes in water quality, and are particularly susceptible to lake...