[BCNnet] Two Recent Bird Articles of Interest
Joe Suchecki
issuesman50@yahoo.com
Tue, 2 Sep 2003 18:50:58 -0700 (PDT)
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Thought the listserve readers would be interested in two bird conservation/management articles that appeared in the latest edition of The Auk(Vol 120, No. 3 July 2003), the Journal of the American Ornithologists Union.
The first reported on a study of Bobolinks in northern Iowa that examined densities and territories of Bobolinks and their relation to edge habitat. The study by Fletcher and Koford from Iowa State found that Bobolinks were less abundant near edge habitat, but importantly found that Bobolink density was lowest near woodland edges and that Bobolinks also nested farther away from woodland edges compared to either agricultural fields or roadways. They concluded that Bobolinks actively avoided woodland edge habitat. Densities near woodland edges were about half that near agricultural edges. Densities also increased as you got further from edge habitat with virtually no Bobolinks within 25 meters of a woodland edge.
This study reinforces and provides good supporting evidence for the need to remove woody vegetation and treelines from grassland bird habitat. Just removing a tree line edge will greatly improve the habitat for Bobolinks and favorably alter the habitat to allow more birds to nest. It is good evidence to cite when justifying the need to remove woody vegetation and trees in areas grassland being managed for birds.
The second study looked at Nesting Wood Thrushes in burned and unburned oak woodlands in southern Ohio. This study by Artman and Downhower examined the nesting populations of Wood Thrushes in oak forest plots that had been managed through prescribed burns and similar plots that were not burned.
They found no difference in local population levels of Wood Thrushes between burned and unburned plots even though the habitat characteristics of the burned plots changed and there was a reduction in understory vegetation. They also found no difference in nest success between burned and unburned plots, although they noted that nest success was greater for nests placed higher off the ground. They concluded that the Wood Thrush seemed to adapt to losses in lower vegetation by using taler and larger diameter saplings in burned areas. One caveat of the study was that the prescribed burns were fairly low intensity and that varied moisture levels in burned areas maintained some nest sites.
The results of the study partially address a concern about the effects of prescribed burning of oak woodlands as a management tool on Wood Thrush populations.
Joe Suchecki
Naperville
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<DIV>
<DIV>Thought the listserve readers would be interested in two bird conservation/management articles that appeared in the latest edition of The Auk(Vol 120, No. 3 July 2003), the Journal of the American Ornithologists Union.</DIV>
<DIV> </DIV>
<DIV>The first reported on a study of Bobolinks in northern Iowa that examined densities and territories of Bobolinks and their relation to edge habitat. The study by Fletcher and Koford from Iowa State found that Bobolinks were less abundant near edge habitat, but importantly found that Bobolink density was lowest near woodland edges and that Bobolinks also nested farther away from woodland edges compared to either agricultural fields or roadways. They concluded that Bobolinks actively avoided woodland edge habitat. Densities near woodland edges were about half that near agricultural edges. Densities also increased as you got further from edge habitat with virtually no Bobolinks within 25 meters of a woodland edge.</DIV>
<DIV> </DIV>
<DIV>This study reinforces and provides good supporting evidence for the need to remove woody vegetation and treelines from grassland bird habitat. Just removing a tree line edge will greatly improve the habitat for Bobolinks and favorably alter the habitat to allow more birds to nest. It is good evidence to cite when justifying the need to remove woody vegetation and trees in areas grassland being managed for birds.</DIV>
<DIV> </DIV>
<DIV>The second study looked at Nesting Wood Thrushes in burned and unburned oak woodlands in southern Ohio. This study by Artman and Downhower examined the nesting populations of Wood Thrushes in oak forest plots that had been managed through prescribed burns and similar plots that were not burned.</DIV>
<DIV> </DIV>
<DIV>They found no difference in local population levels of Wood Thrushes between burned and unburned plots even though the habitat characteristics of the burned plots changed and there was a reduction in understory vegetation. They also found no difference in nest success between burned and unburned plots, although they noted that nest success was greater for nests placed higher off the ground. They concluded that the Wood Thrush seemed to adapt to losses in lower vegetation by using taler and larger diameter saplings in burned areas. One caveat of the study was that the prescribed burns were fairly low intensity and that varied moisture levels in burned areas maintained some nest sites.</DIV>
<DIV> </DIV>
<DIV>The results of the study partially address a concern about the effects of prescribed burning of oak woodlands as a management tool on Wood Thrush populations.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Joe Suchecki</DIV>
<DIV>Naperville</DIV></DIV><p><hr SIZE=1>
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