Bird Movement and Migration
Migration is an amazing annual event. Every year billions of animals – birds, mammals, insects, and fish – make long-distance journeys from breeding grounds to wintering grounds. Most northern hemisphere birds migrate southward, but there are many other ways that birds move seasonally. If we want to protect birds that take these long distance journeys, we need to understand why they move, why they stay, how they move, and why they go where they go.
Our team studies the behaviors, drivers, and migration endpoints of individual birds throughout North America and world-wide. Most of this work is done using tracking devices, such as Global Positioning System (GPS) telemetry or light-level geolocators. Bird movement data can then be linked to other datasets, such as habitat or topographic maps that tell us details about sites birds spend time in or fly by. Our approach reveals the details of the movements of these remarkable birds and how they use different landscapes across continents.
Using GPS Telemetry to Track Golden Eagles
We are tracking migratory movements of golden eagles with GPS-telemetry systems. GPS data can tell us the altitude at which eagles are flying and relate their position to the landform directly below them. For example, we’ve learned that migrating eagles fly at lower altitudes over steeper terrain and at higher altitudes over flat terrain. This fundamental insight into eagle flight strategy helps us better understand the ways that eagles use updrafts to subsidize their flight and identifies reasons that eagles may be at risk from wind turbines constructed along their migration pathway (see “Interaction between Energy Development and Raptors”).
We also evaluate conditions under which eagles choose to migrate by linking GPS telemetry data to large-scale modeled weather data. Eagles respond to weather conditions while flying, while on the ground, or both. Understanding how weather patterns and eagle migration behavior are linked provides important insight into how changes in climate and weather could affect eagle ecology.
Raptor Migration in Asia
Our team also studies migration of eagles and falcons in central Asia. Central Asia is politically important and has some of the largest remaining intact grassland ecosystems anywhere in the world. We use GPS-telemetry systems to track movements of imperial eagles and white-tailed sea eagles from Kazakhstan to wintering grounds in the Middle-East, and light-level geolocators to track movements of red-footed falcons from Kazakhstan to southern Africa and back.
Katzner, Todd -
Mallon, J.M., Bildstein, K.L., Katzner, T.E., 2016, In-flight turbulence benefits soaring birds: Auk, v. 133, p. 79-85, http://dx.doi.org/10.1642/AUK-15-114.1. [Details]
Poessel, S.A., Bloom, P.H., Braham, M.A., Katzner, T.E., 2016, Age- and season-specific variation in local and long-distance movement behavior of golden eagles: European Journal of Wildlife Research, p. online, http://dx.doi.org/10.1007/s10344-016-1010-4. [Details]
Tracy, D., Madden, M.C., Sebes, J.B., Bloom, P., Katzner, T.E., Fisher, R.N., 2016, Biotelemetry data for golden eagles (Aquila chrysaetos) captured in coastal southern California, November 2014–February 2016: U.S. Geological Survey Data Series 994, p. 32, http://dx.doi.org/10.3133/ds994. [Details]
Behmke, S., Fallon, J.A., Duerr, A., Lehner, A., Buchweitz, J., Katzner, T.E., 2015, Chronic lead exposure is epidemic in obligate scavenger populations in eastern North America: Environment International, v. 79, p. 51-55, http://dx.doi.org/10.1016/j.envint.2015.03.010. [Details]
Duerr, A., Miller, T.A., Duerr, K.C., Lanzone, M., Fesnock, A., Katzner, T.E., 2015, Landscape-scale distribution and density of raptor populations wintering in anthropogenic-dominated desert landscapes: Biodiversity and Conservation, v. 24, no. 10, p. 2365-2381, http://dx.doi.org/10.1007/s10531-015-0916-6. [Details]