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At least 91 records · Page 5Linked to original sources
USGS1989

Considerations for monitoring raptor population trends based on counts of migrants

Various problems were identified with standardized hawk count data as annually collected at six sites. Some of the hawk lookouts increased their hours of observation from 1979-1985, thereby confounding the total counts. Data recording and missing data hamper coding of data and their use with modern analytical techniques. Coefficients of variation among years in counts averaged about 40%. The advantages and disadvantages of various analytical techniques are discussed including regression, non-parametric rank correlation trend analysis, and moving averages.

Book chapter↗
USGS2000

DC birdscape: a program for monitoring neotropical migrant birds in Washington, DC

Urban and suburban habitats often contain a variety of Neotropical migratory birds, but are poorly sampled by programs such as the North American Breeding Bird Survey. DC Birdscape was developed to inventory and monitor birds in Washington, D.C. Birds were surveyed using a systematic sample of point counts during 1993-1995. Results indicate that species richness of Neotropical migratory birds varied among land-use categories, and that maximum species richness occurred in parkland habitats. Although DC Birdscape has provided relevant information on bird distribution and species richness, it is unclear whether the information is of sufficient management interest to support its continuation as a long-term monitoring program.

Book chapter↗
USGS1993

Monitoring neotropical migrants on managed land: When, where, why

Relevant wildlife monitoring on managed lands lies somewhere between monitoring everything and monitoring nothing. Knowing the population status of all birds on a managed area would be potentially useful information but would be costly to collect, but without monitoring no link between management and wildlife populations can be made. A decision making process for developing appropriate monitoring programs on managed lands is outlined.

Book chapter↗
USGS1981

Body lipids and pesticide burdens of migrant blue-winged teal

Blue-winged Teal were collected before and after their migration to wintering grounds in Latin America. Pesticide burdens, body weights, and lipid levels of carcasses were determined. Only DDE and dieldrin were detected in a small proportion of the samples and then at concentrations far below known-effect levels. Residue loads, because of their infrequency, were not significantly correlated with overall body weight and percent lipid. Body weights among most age and sex classes did not differ in either fall or spring, nor did percent lipid in any instance. However, body weights and lipid levels were significantly correlated; as body weight increased so did percent lipid. Thus, the extreme variability in body weight appears to be a function of the amount of fat present and not overall body size, age, or sex.

Journal of Field Ornithology↗
USGS1998

Winter habitat of Kirtland's warbler: an endangered nearctic/neotropical migrant

Habitats of Kirtland?s Warbler (Dendroica kirtlandii) on the wintering grounds in the Bahama Archipelago are presented based upon data from 29 specimens, two bandings, and 67 sightings of at least 61 individuals on 13 islands scattered through the region. Major emphasis is placed on a study site in central Eleuthera, with additional information on sites on Grand Turk, North Caicos, and Crooked Island. The warblers used upland habitats that have a low shrub/scrub component with a patchiness of small openings and openings within the vegetation at the ground level. Six broad habitats were identified as being used: Natural Shrub/Scrub, Secondary Shrub/Scrub, Low Coppice, Pineland Understory, Saline/Upland Ecotone, and Suburban; High Coppice is not used. The structure and floristic composition of the habitats are described. Observations (N=451) of a Kirtland?s Warbler male (uniquely color banded) and female over three months indicated the birds generally stayed on or near the ground, generally < 3 m (98% of observations), and used a territory of 8.3 ha. A crude estimate of potential winter habitat suggests that there is more than an adequate amount in the Bahama Archipelago for the currently small warbler population (733 singing males in 1997) and allows for a considerable population increase. No serious future threat to the amount of that habitat is foreseen.

The Wilson Bulletin↗
USGS2010

Influence of a low intensity electric sea lion deterrence system on the migratory behavior of fishes in the upstream migrant tunnel (UMT) at Bonneville Dam.

Predation by pinnipeds, such as California sea lions (Zalophus alifornianus), Pacific harbor seals (Phoca vitulina), and Stellar sea lions (Eumetopias jubatus) on returning adult Pacific salmon (Oncorhynchus spp.) in the Columbia River basin has become an increasing concern for fishery managers trying to conserve and restore threatened and endangered runs of salmonids. As a result, Smith-Root Incorporated (SRI; Vancouver, Washington) proposed a demonstration project to evaluate the potential of an electrical array to deter marine mammals (SRI 2007). The objective of their work was to develop, deploy, and evaluate a passive, integrated electric and sonar array that selectively inhibits upstream marine mammal movements and predation, without injuring pinnipeds or affecting anadromous fish migrations. However, before such a device could be placed in the field, concerns by regional fishery managers about the potential effects of such a device on the migratory behavior of or injury to Pacific salmon, steelhead (O. mykiss), Pacific lampreys (Entoshpenus tridentata), and white sturgeon (Acipenser transmontanus) needed to be addressed.

Oregon, Washington↗
USGS2015

Evaluating predictors of local dabbling duck abundance during migration: Managing the spectrum of conditions faced by migrants

The development of robust modelling techniques to derive inferences from large-scale migratory bird monitoring data at appropriate scales has direct relevance to their management. The Integrated Waterbird Management and Monitoring programme (IWMM) represents one of the few attempts to monitor migrating waterbirds across entire flyways using targeted local surveys. This dataset included 13,208,785 waterfowl (eight Anas species) counted during 28,000 surveys at nearly 1,000 locations across the eastern United States between autumn 2010 and spring 2013 and was used to evaluate potential predictors of waterfowl abundance at the wetland scale. Mixed-effects, log-linear models of local abundance were built for the Atlantic and Mississippi flyways during spring and autumn migration to identify factors relating to habitat structure, forage availability, and migration timing that influence target dabbling duck species abundance. Results indicated that migrating dabbling ducks responded differently to environmental factors. While the factors identified demonstrated a high degree of importance, they were inconsistent across species, flyways and seasons. Furthermore, the direction and magnitude of the importance of each covariate group considered here varied across species. Given our results, actionable policy recommendations are likely to be most effective if they consider species-level variation within targeted taxonomic units and across management areas. The methods implemented here can easily be applied to other contexts, and serve as a novel investigation into local-level population patterns using data from broad-scale monitoring programmes.

Wildfowl↗
USGS2006

Survival estimates of migrant juvenile salmonids through Bonneville Dam using radio telemetry, 2005

During 2005, we evaluated the survival of radio-tagged yearling and subyearling Chinook salmon and steelhead trout through the Bonneville Dam spillway, powerhouses 1 and 2, the corner collector and juvenile bypass system (JBS) at powerhouse 2, and through all routes collectively using the route-specific survival model. Radio-tagged fish were released at The Dalles Dam and in the tailrace of Bonneville Dam and were interrogated at Bonneville Dam and three radio-telemetry arrays below Bonneville Dam. We also evaluated the survival of radio-tagged yearling and subyearling Chinook salmon and steelhead trout using paired releases through the ice and trash sluiceway at Bonneville Dam’s powerhouse 1. Site-specific releases were made directly into the ice and trash sluiceway and in the tailrace of Bonneville Dam below the outfall of powerhouse 2 juvenile bypass system.

Oregon, Washington↗