| Accession Number | 5003440 |
| Title | The hormonal control and the effects of endocrine-active contaminants on avian |
| secondary sex characteristics |
| Project Description | Measuring the effects of endocrine-active chemicals (EACs) on wildlife is a challenge that is made |
| complicated by the complexity of the endocrine system and the wide variety of reproductive |
| patterns seen in nature. Biomarkers with some utility in the field to assess the effects of exposure |
| to EACs will be an important tool for the wildlife biologist to evaluate the impact of these |
| compounds on populations under their management. Morphological secondary sexual |
| characteristics of birds are features that have promise as biomarkers for EACs: they are readily |
| visible, measurements can be made without killing the bird, aspects of plumage (coloration and |
| pattern) and the color of soft parts are under some degree of hormonal control and often these |
| characters are crucial to reproductive success through courtship and mating. There is useful |
| information extant on the hormonal control of molting schedules in many bird species, and |
| important but less extensive information on the control of color and patterning of plumage and bills |
| and other dermal structures. More information on the degree of hormonal control of avian |
| secondary sexual characteristics, and the sensitivity to known EDCs is needed before these can |
| be useful biomarkers in birds. This project will develop measures for plumage, soft parts (bill and |
| dermal structures) color and pattern in American kestrels (Falco sparverius). In addition, |
| experiments will characterize the effects of both steroid hormones and EACs on plumage and soft |
| parts in species from two different groups of birds: one that develops secondary sexual |
| characteristics in advance of breeding (i.e. has an alternate plumage) and one that does not (i.e. |
| has only a basic plumage). These two groups of birds differ in the hormonal control of their |
| plumage. |
| Keywords | birds, contaminants, endocrine disruptors, human impacts, kestrels, toxicology, |
| Principal | John B French, USGS Patuxent Wildlife Research Center: john_b_french@usgs.gov; |
| Investigators |
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