Grasslands and shrub steppe within the Naval Weapons Systems Training Facility (NWSTF) in Boardman, Oregon, have been identified as important habitat for the imperiled long-billed curlew, North America’s largest shorebird. However, there is still much to be learned about curlew status at the NWSTF and overall habitat requirements for this species. The USGS has initiated a new study to estimate long-billed curlew abundance and density at NWSTF using unmanned aerial vehicles to conduct surveys.
Ecosystems - Wildlife
Condors and vultures are the only terrestrial vertebrates that scavenge for all their food, and these birds move widely to locate unpredictable, patchily distributed food sources. USGS researchers and collaborators used high-resolution global positioning system (GPS) data to evaluate the home range of both wild- and captive-reared endangered California condors. They examined whether captive-reared birds’ characteristics and factors influenced their monthly home range size. Adult birds’ home ranges were larger than ranges of immature birds.
Federal, state, and Tribal natural resources management agencies conduct wildlife population counts either from the ground or via manned, low-altitude aircraft flights; both of these methods have limitations of accuracy, cost, safety, and timeliness. This project tested the capability of thermal infrared (TIR) sensors aboard the Raven RQ-11A small unmanned aircraft system (sUAS) to provide a source of accurate population estimates of sandhill cranes (Grus canadensis) and detection of breeding greater sage-grouse (Centrocercus urophasianus) in Colorado.
Various methods of obtaining population data are being evaluated to select the best method for estimating population sizes of ground-nesting waterbirds at the Anaho Island National Wildlife Refuge. These colonial nesting birds are sensitive to human disturbance and will abandon their nests if appropriate methods are not utilized during population surveys.
Imagery collected via a small unmanned aircraft system (sUAS) is being used to assess available breeding habitat of Federal- and State-listed threatened and endangered bird species at Havasu National Wildlife Refuge (NWR) near Needles, California. High-resolution, color-infrared imagery collected with sUAS is being analyzed in conjunction with vegetation, topography, bathymetry, differential-GPS, and species-specific breeding habitat criteria.
Most North American ospreys breed in northern latitudes and migrate long distances to and from tropical wintering grounds. Although the fall migration patterns of these ospreys have been well studied, very little has been published about spring migration. USGS and other researchers used satellite telemetry to determine the timing and duration of osprey spring migratory routes from 1997 to 2013. The researchers also compared spring and fall migrations among male and female ospreys from three breeding populations (east coast, midwestern, and western).
At three locations in the Sacramento, California area, the USGS Western Remote Sensing and Visualization Center (WRSVC) has utilized tripod-mounted lidar to map the three-dimensional (3D) extent of mammal burrows and tree-root casts, which can substantially compromise the structural integrity of flood-control levees. The burrows and casts were filled with grout and/or polyurethane and then carefully excavated, exposing the network of interconnected voids. An incremental sequence of excavations followed by lidar scans enabled 3D mapping of the burrow and cast networks.
Risk of golden eagle collisions with wind turbines is influenced by the altitude at which the birds fly. Topographic features drive eagle flight because lift is dependent on the slope, aspect, and cover type over which they fly. The USGS is leading an evaluation of the relationship between topography and eagle flight altitude to infer risk to eagles from turbine development in the Mojave Desert, California.
USGS scientists at the Great Lakes Science Center in Michigan are using acoustic telemetry to describe the movements of fish in the St. Clair-Detroit River system on the border between Michigan and Ontario, Canada. This research will be used to support Great Lakes fishery managers in restoring native species, such as lake sturgeon, and controlling exotic species, such as sea lamprey.
Condor populations recovering in California face numerous threats, including the development of wind-energy facilities within their range. To understand how condor flight behavior may expose them to risk from wind energy, USGS, U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, and Bureau of Land Management researchers are initiating a new study to track condor flight using high-frequency Global Positioning System-Global System for Mobile Communication (GPS-GSM) telemetry systems.