Effects of nest parasitism by the brown-headed cowbird on nesting success of the California gnatcatcher
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Published source details
Braden G.T., McKernan R.L. & Powell S.M. (1997) Effects of nest parasitism by the brown-headed cowbird on nesting success of the California gnatcatcher. The Condor, 99, 858-865.
Published source details Braden G.T., McKernan R.L. & Powell S.M. (1997) Effects of nest parasitism by the brown-headed cowbird on nesting success of the California gnatcatcher. The Condor, 99, 858-865.
Actions
This study is summarised as evidence for the following.
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Remove/control adult brood parasites Action Link |
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Remove/control adult brood parasites
A before-and-after study at four coastal scrub sites in California, USA (Braden et al. 1997), found that levels of parasitism of California gnatcatcher Polioptila californica nests (initiated after 5th May) by brown-headed cowbirds Molothrus ater was significantly lower in 1994-5, following the removal of a total of 507 cowbirds over the two years, compared to in 1992-3 (10% of 132 nests parasitized in 1994-5 vs. 46% of 107 nests in 1992-3). However, nest success over the whole breeding season was no higher in years with cowbird control (21.7% of nests successful in 1994-5 vs. 11.2% in 1992-3).
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