Geology topics

Laura Kearns

Publications and source records attributed to Laura Kearns.

2 recordsLinked to original sources

USGS2024

High variability of migration strategies in a re-established Cygnus buccinator (Trumpeter Swan) population

The Interior Population (IP) of Cygnus buccinator (Trumpeter Swan), formerly extirpated by market hunting, was re-established in eastern North America by releasing individuals from both migratory and non-migratory populations. Their current annual movement patterns are largely unknown. We deployed 113 GPS-GSM transmitters on IP C. buccinator in 6 U.S. states and 1 Canadian province across the current IP breeding range. Using data from 252 “swan-years”, we estimated migration phenology using piecewise regression models fit to each yearly time-series of displacement from the breeding site. We fit a latent-state model to characterize population-level associations between breeding latitude and maximum extent of migration, and linear mixed models to quantify associations between individual characteristics (e.g., breeding status, sex) and migration phenology. At the individual level, 59% of swans moved to distant nonbreeding-period areas (long-distance migration, defined as moving >100 km from the breeding site), 16% exhibited regional migration (25–100 km from breeding site), 19% exhibited non-migratory but local movements (<25 km from breeding site), and 6% exhibited multiple migration strategies. Swans breeding at more-northern latitudes departed their territories earlier in autumn, returned later in the spring, and migrated farther from their breeding territories than those breeding at more southern latitudes. Although the population-level association between migration extent and breeding latitude was positive, some individuals remained close to the location of their breeding site during the nonbreeding period. Breeding swans departed later in the autumn than non-breeders, but breeding status did not have a strong association with arrival in the spring. IP C. buccinator are partial migrants, with a continuum of strategies that vary latitudinally, from local movements to long-distance migration. Much of the variability in movement patterns related to factors tied to natural history demands (e.g., breeding status) and response to environmental conditions (e.g., through associations with breeding latitude).

Ornithology↗

USGS2023

Wetland management practices and secretive marsh bird habitat in the Mississippi Flyway: A review

Management regimes on publicly owned freshwater wetlands in the Mississippi Flyway of North America (i.e., Flyway) have historically emphasized waterfowl, but there is limited information on how waterfowl-focused wetland management affects other wetland-dependent wildlife. Secretive marsh birds (SMBs) depend on wetlands with emergent vegetation throughout their migratory life cycle and often encounter vegetation and water conditions resulting from waterfowl-focused management regimes. Thus, there is a need for better understanding of how SMBs are affected by wetland management and the extent to which waterfowl-focused management regimes provide habitat for SMBs. In this review, we identify the vegetation and water conditions resulting from typical management objectives on freshwater emergent wetlands in the Flyway, review and qualitatively synthesize results from studies that directly evaluate how wetland management practices affect SMBs or their habitat, and assess how the vegetation and water conditions being produced for target species (mainly waterfowl) align with SMB habitat requirements. We searched online databases and used Google Scholar to locate peer-reviewed literature, technical reports, and graduate theses that pertained to responses of SMBs or their habitat to water-level manipulation, herbicide application, prescribed fire, disking, mowing, and planting crops. There are several management strategies that complement SMBs and waterfowl, such as reducing cover of woody species and providing flooded emergent vegetation. We also highlight management strategies that may not currently align with SMB life-cycle needs and suggest adjustments that might promote habitat for SMBs while still achieving waterfowl population objectives. For example, adjusting the dates and duration of spring water-level drawdowns on a portion of wetlands within a larger complex can provide for spring migrating waterfowl and ensure habitat for migrating and nesting SMBs. Ideally, future studies would address how modifications to management practices affect SMBs and monitor potential effects on waterfowl, resulting in a more holistic approach to wetland management.

The Journal of Wildlife Management↗