University of New Hampshire
Mentor: Dr. Adrienne Kovach, Department of Natural Resources and the Environment
A comparative analysis of the nest structure of Saltmarsh, Nelson’s, and Saltmarsh-Nelson’s hybrid sparrows
Very few species are able to inhabit the harsh environment provided by salt marshes. The flood tides which occur every month inundate the marsh. Saltmarsh sparrows (Ammodramus caudacutus), Nelson’s sparrows (Ammodramus nelsoni), and their hybrids are ground nesting birds which are able to use this hostile habitat. However, the flood tides often cause their nests to fail by washing the eggs and nestlings out. It has been suggested that some features of nest structure may contribute to reproductive success. This study will collect data on nest structure characteristics, such as the height of the nest and presence and level of completion of a woven grass dome over the nest cup, of all three groups at four study sites in Maine, New Hampshire, and Massachusetts. The data will be compared across species and track the changes in nest structure of individual females. The prediction of this study is that Saltmarsh sparrows will build nests that have characteristics that make them more resistant to flooding than Nelson’s or hybrid nests. This study also hypothesizes that females will change their nest structure following a failure due to flooding. Both of the species of interest are currently of conservation concern. Sea level rise as a result of climate change causes more intense and more frequent flooding of the marshes. Hybridization causes complications in management of the species and could result in behavioral changes that would reduce the fitness of the species. We need to fully understand the nesting ecology of these species and the impacts of hybridization to create effective conservation strategies for these threatened birds.