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Relationship Between Reproductive Hormones And Migration Distance In A Polygynous Songbird, The Red‑Winged Blackbird (Agelaius Phoeniceus), Michelle A. Eshleman, Page E. Klug, Esther Morales‑Vega, Björn Wissel, Timothy J. Grelves
Relationship Between Reproductive Hormones And Migration Distance In A Polygynous Songbird, The Red‑Winged Blackbird (Agelaius Phoeniceus), Michelle A. Eshleman, Page E. Klug, Esther Morales‑Vega, Björn Wissel, Timothy J. Grelves
USDA Wildlife Services: Staff Publications
Many bird species migrate to southern overwintering locations to avoid harsh conditions at their breeding grounds, but at the cost of an energetically demanding migration that may delay their spring reproductive development. Previous work on the relationship between migration distance and reproductive readiness has primarily focused on early season baseline testosterone in both males and females. However, for females, testosterone alone may not be the appropriate measurement of reproductive development. Estradiol, a metabolite of testosterone that is essential for breeding behaviors and reproduction, should also be measured. Furthermore, baseline testosterone varies throughout the day and may change due to social …
A Framework For Spatial Risk Assessments: Potential Impacts Of Nonindigenous Invasive Species On Native Species, Craig R. Allen, Alan R, Johnson, Leslie Parris
A Framework For Spatial Risk Assessments: Potential Impacts Of Nonindigenous Invasive Species On Native Species, Craig R. Allen, Alan R, Johnson, Leslie Parris
Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications
Many populations of wild animals and plants are declining and face increasing threats from habitat fragmentation and loss as well as exposure to stressors ranging from toxicants to diseases to invasive nonindigenous species. We describe and demonstrate a spatially explicit ecological risk assessment that allows for the incorporation of a broad array of information that may influence the distribution of an invasive species, toxicants, or other stressors, and the incorporation of landscape variables that may influence the spread of a species or substances. The first step in our analyses is to develop species models and quantify spatial overlap between stressor …