Constant-effort mist netting is performed to study survivorship patterns. In 2010 1,562 birds were captured and the capture rates (number of adult birds captured/net hour) in 2010 were similar to previous years. Most commonly captured birds included the Yellow warbler (Dendroica petechia; 360), Western Tanager (Piranga ludoviciana; 126), American robin (Turdus migratorius; 106), Song sparrow (Melospiza melodia; 72), and Cedar Waxwing (Bombycilla cedrorum; 64)
Productivity estimates (ratio of hatch-year: after hatch-year captures) from 1998-2009 indicate variability in population trends for all birds captured as well as our focal riparian-nesting species. Banding data does not appear to show a strong relationship between productivity and housing development.
Overall nest survival in 2009 was 52%. Overall nest survival in 2010 was 24%. A nest was considered successful if at least one nestling fledged. Preliminary analyses of nest survival data indicate that human development may reduce nest survival, though the mechanism responsible for decreased nest survival is not clear. Analysis of the 2008 -2010 nesting data, combined, showed a strong inverse relationship between productivity and housing development. More developed sites showed lower nest survival probabilities while less developed sites, showed higher nest survival. This trend indicates that, while songbirds breed in sites surrounded by development, the likelihood of fledging young is reduced relative to sites in less disturbed landscapes.
Interestingly, however, when considered independently the data from 2010 show a different trend with survival rates being highest in Karns Meadow, the most developed site, and in Blacktail Ponds, one of the least developed sites. Earthwatch scientists hypothesize that this trend may be due to changing weather patterns experienced in the spring and summer of 2010.
The project promotes responsible stewardship and natural resource management by working with both citizen scientists as well as acting as a resource to local town and state governing bodies in their creation and amendment of development and management plans.
DeSante, D.F. and D. R. Kaschube (2009). The monitoring avian productivity and survivorship (MAPS) program 2004, 2005, and 2006 report. Bird Populations, 9: 86-169