Research Training ProgramSmithsonian
Institution
|
|
 Tristan Kimbrell Kansas State University Manhattan, Kansas Gary Graves, Ph.D. Department of Vertebrate Zoology Donald Ortner, Ph.D. Department of Anthropology Supervising Scientists "This experience has helped to finalize my commitment to a career in science." |
 |
|
|
Age-Related Changes in the Cross-Sectional Histomorphology
of Warbler Long BonesABSTRACT
Determining the ages of organisms in a population is an important part of many branches of biology. Currently, the only way to accurately age birds in the wild is to band them as chicks, a rather time-consuming venture. Recently, ornithologists have begun to explore whether layers of bone on the interior surface (endosteal surface) of the long bones can be used to age birds. A recent study of four bird species from four different families found that the endosteal bone layers correlated on a one-to-one basis with the known age of the birds. It is hypothesized the layers are added annually to the long bones either in response to biomechanical stress or for calcium storage. The study, however, only examined species of relatively large birds. This project explores whether a smaller species of bird, the black-throated blue warbler (Dendroica caerulescens), also exhibits layers of bone on the endosteal surface of long bones, and whether those layers can be used to age individuals of the species. To look for bone layers, twenty humeri and twenty-two femora were thin-sectioned from known-age warblers and the sections were examined under a light microscope. Bone layers were not found in any of the forty-two sections examined. To determine if additional bone was added annually but layering was not visible, the area of each bone section was examined. If layers were added annually to the long bones, older individuals should have bone sections of larger area than younger individuals. It was found, however, that there was no difference in area between older and younger warblers. These results are a preliminary indication that bone layering in the long bones of black-throated blue warblers does not occur and is therefore not a viable aging method for this species.
This research was supported by a grant from the National Science Foundation, Research Experience for Undergraduates Program (award number DBI-9531331)