Date: May 31, 2017
Source: American Ornithological
Society Publications Office
Theory says that birds should
choose nest sites that minimize their risk of predation, but studies often fail
to show a connection between nest site selection and nest survival.
Understanding these relationships can be key for managing declining species, and
a new study from The Condor: Ornithological Applications explores the nest site
preferences of Bachman's Sparrow, a vulnerable songbird dependent on regularly
burned longleaf pine forests in the southeastern U.S.
Jason Winiarski of North Carolina
State University and his colleagues monitored a total of 132 Bachman's Sparrow
nests in two regions of North Carolina, the Coastal Plain and the Sandhills,
measuring a variety of vegetation characteristics. They found several
differences between the two regions in what sparrows looked for in a nest site
-- in the Coastal Plain, they favored low grass density and greater woody
vegetation density, while birds in the Sandhills selected intermediate grass
density and greater tree basal area. However, none of these features turned out
to be related to nest survival.
According to the researchers, the
differences between the two regions are likely due to differences in the
available plant communities. Bachman's Sparrows also could be selecting nest
sites that allow easy access to nests or maximize the survival of fledglings
once they leave, and these aspects may warrant further investigation.
Regardless, Winiarski and his colleagues believe their results show the
importance of management that mimics historical fire regimes in longleaf pine
ecosystems, in order to maintain the diverse groundcover types used by the
birds.
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