As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Thursday, 22 June 2017

New details on nest preferences of declining sparrow




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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