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--Apple-Mail-1-465658698
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Hello,
Last year the increasing Bald Eagle population apparently had a lot =20
of negative impact on seabird breeding colonies in parts of Cape =20
Breton. Several people reported their observations during a recent =20
Bird Society meeting.
I just found the following paper looking into a similar issue on the =20
Pacific coast. One or the other may be interested to study the whole =20=
thing. Not sure how access to the pdf is handled by the publisher. =20
If you can't get it let me know and I will send you a copy (no =20
pictures, dry science stuff).
Here's the abstract:
Pleistocene to historic shifts in bald eagle diets on the Channel =20
Islands, California
Seth D. Newsomea,b,1,
Paul W. Collinsc,
Torben C. Rickd,
Daniel A. Guthriee,
Jon M. Erlandsonf, and
Marilyn L. Fogelb
+ Author Affiliations
aDepartment of Zoology and Physiology, University of Wyoming, =20
Laramie, WY 82070;
bGeophysical Laboratory, Carnegie Institution of Washington, =20
Washington, DC 20015;
c Santa Barbara Museum of Natural History, Santa Barbara, CA 93105;
dArchaeobiology Program, Department of Anthropology, National Museum =20
of Natural History, Smithsonian Institution, Washington, DC 20013;
eJoint Science Department, Claremont McKenna College, Claremont, CA =20
91711; and
fMuseum of Natural and Cultural History, University of Oregon, =20
Eugene, OR 97403
Edited by Thure E. Cerling, University of Utah, Salt Lake City, UT, =20
and approved April 8, 2010 (received for review November 10, 2009)
Abstract
Studies of current interactions among species, their prey, and =20
environmental factors are essential for mitigating immediate threats =20
to population viability, but the true range of behavioral and =20
ecological flexibility can be determined only through research on =20
deeper timescales. Ecological data spanning centuries to millennia =20
provide important contextual information for long-term management =20
strategies, especially for species that now are living in relict =20
populations. Here we use a variety of methods to reconstruct bald =20
eagle diets and local abundance of their potential prey on the =20
Channel Islands from the late Pleistocene to the time when the last =20
breeding pairs disappeared from the islands in the mid-20th century. =20
Faunal and isotopic analysis of bald eagles shows that seabirds were =20
important prey for immature/adult eagles for millennia before the =20
eagles=92 local extirpation. In historic times (A.D. 1850=961950), =20
however, isotopic and faunal data show that breeding bald eagles =20
provisioned their chicks with introduced ungulates (e.g., sheep), =20
which were locally present in high densities. Today, bald eagles are =20
the focus of an extensive conservation program designed to restore a =20
stable breeding population to the Channel Islands, but native and =20
nonnative prey sources that were important for bald eagles in the =20
past are either diminished (e.g., seabirds) or have been eradicated =20
(e.g., introduced ungulates). In the absence of sufficient resources, =20=
a growing bald eagle population on the Channel Islands could expand =20
its prey base to include carrion from local pinniped colonies, exert =20
predation pressure on a recovering seabird population, and possibly =20
prey on endangered island foxes.=20
=20=
--Apple-Mail-1-465658698
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<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">Hello,
<div><br class=3D"webkit-block-placeholder"></div><div>Last year the =
increasing Bald Eagle population apparently had a lot of negative impact =
on seabird breeding colonies in parts of Cape Breton. =A0Several people =
reported their observations during a recent Bird Society =
meeting.</div><div>I just found the following paper looking into a =
similar issue on the Pacific coast. =A0One or the other may be =
interested to study the whole thing. =A0Not sure how access to the pdf =
is handled by the publisher. If you can't get it let me know and I will =
send you a copy (no pictures, dry science stuff).</div><div>Here's the =
abstract:</div><div><br class=3D"webkit-block-placeholder"></div><div><h1 =
id=3D"article-title-1">Pleistocene to historic shifts in bald eagle =
diets on the Channel Islands, California</h1> <div =
class=3D"contributors"> <ol class=3D"contributor-list" =
id=3D"contrib-group-1"> <li class=3D"contributor" =
id=3D"contrib-1"><span class=3D"name"><a class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DSeth+D.+Newsome&sortspec=3D=
date&submit=3DSubmit">Seth D. Newsome</a></span><a id=3D"xref-aff-1-1"=
class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-1"><su=
p>a</sup></a><span class=3D"xref-sep">,</span><a id=3D"xref-aff-2-1" =
class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-2"><su=
p>b</sup></a><span class=3D"xref-sep">,</span><a id=3D"xref-corresp-1-1" =
class=3D"xref-corresp" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#corresp-1"=
><sup>1</sup></a>, </li> <li =
class=3D"contributor" id=3D"contrib-2"><span class=3D"name"><a =
class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DPaul+W.+Collins&sortspec=3D=
date&submit=3DSubmit">Paul W. Collins</a></span><a id=3D"xref-aff-3-1"=
class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-3"><su=
p>c</sup></a>, </li> <li =
class=3D"contributor" id=3D"contrib-3"><span class=3D"name"><a =
class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DTorben+C.+Rick&sortspec=3D=
date&submit=3DSubmit">Torben C. Rick</a></span><a id=3D"xref-aff-4-1" =
class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-4"><su=
p>d</sup></a>, </li> <li =
class=3D"contributor" id=3D"contrib-4"><span class=3D"name"><a =
class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DDaniel+A.+Guthrie&sortspe=
c=3Ddate&submit=3DSubmit">Daniel A. Guthrie</a></span><a =
id=3D"xref-aff-5-1" class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-5"><su=
p>e</sup></a>, </li> <li =
class=3D"contributor" id=3D"contrib-5"><span class=3D"name"><a =
class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DJon+M.+Erlandson&sortspec=
=3Ddate&submit=3DSubmit">Jon M. Erlandson</a></span><a =
id=3D"xref-aff-6-1" class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-6"><su=
p>f</sup></a>, and </li> <li =
class=3D"last" id=3D"contrib-6"><span class=3D"name"><a =
class=3D"name-search" =
href=3D"http://www.pnas.org/search?author1=3DMarilyn+L.+Fogel&sortspec=
=3Ddate&submit=3DSubmit">Marilyn L. Fogel</a></span><a =
id=3D"xref-aff-2-2" class=3D"xref-aff" =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#aff-2"><su=
p>b</sup></a></li> </ol><p =
class=3D"affiliation-list-reveal"><a =
href=3D"http://www.pnas.org/content/early/2010/04/21/0913011107#" =
class=3D"view-more">+</a> Author Affiliations</p> <ol =
class=3D"affiliation-list hideaffil"> <li =
class=3D"aff"><a id=3D"aff-1" =
name=3D"aff-1"></a><address><sup>a</sup>Department of Zoology and =
Physiology, University of Wyoming, Laramie, WY 82070; =
</address> </li> <li =
class=3D"aff"><a id=3D"aff-2" =
name=3D"aff-2"></a><address><sup>b</sup>Geophysical Laboratory, Carnegie =
Institution of Washington, Washington, DC 20015; =
</address> </li> <li =
class=3D"aff"><a id=3D"aff-3" name=3D"aff-3"></a><address><sup>c</sup> =
Santa Barbara Museum of Natural History, Santa =
Barbara, CA 93105; </address> =
</li> <li class=3D"aff"><a id=3D"aff-4" =
name=3D"aff-4"></a><address><sup>d</sup>Archaeobiology Program, =
Department of Anthropology, National Museum of Natural History, =
Smithsonian Institution, Washington, DC 20013; =
</address> </li> =
<li class=3D"aff"><a id=3D"aff-5" =
name=3D"aff-5"></a><address><sup>e</sup>Joint Science Department, =
Claremont McKenna College, Claremont, CA 91711; and =
</address> </li> <li =
class=3D"aff"><a id=3D"aff-6" =
name=3D"aff-6"></a><address><sup>f</sup>Museum of Natural and Cultural =
History, University of Oregon, Eugene, OR 97403 =
</address> </li> </ol> =
<ol class=3D"fn-track"> <li class=3D"fn-edited-by"=
id=3D"fn-1"><p id=3D"p-1">Edited by Thure E. Cerling, University of =
Utah, Salt Lake City, UT, and approved April 8, 2010 (received for =
review November 10, 2009) =
</p> </li> </ol> =
</div> <div class=3D"section abstract" id=3D"abstract-1"> =
<h2>Abstract</h2><p id=3D"p-3">Studies of current =
interactions among species, their prey, and environmental factors are =
essential for mitigating immediate threats to =
population viability, but the true range of behavioral and ecological =
flexibility can be determined only through research =
on deeper timescales. Ecological data spanning centuries to millennia =
provide important contextual information for =
long-term management strategies, especially for species that now are =
living in relict populations. Here we use a variety of =
methods to reconstruct bald eagle diets and local abundance of their =
potential prey on the Channel Islands from the late Pleistocene =
to the time when the last breeding pairs disappeared from the =
islands in the mid-20th century. Faunal and isotopic analysis =
of bald eagles shows that seabirds were important prey for =
immature/adult eagles for millennia before the eagles=92 local =
extirpation. In historic times (A.D. 1850=961950), =
however, isotopic and faunal data show that breeding bald eagles =
provisioned their chicks with introduced ungulates =
(e.g., sheep), which were locally present in high densities. Today, bald =
eagles are the focus of an extensive conservation =
program designed to restore a stable breeding population to the Channel =
Islands, but native and nonnative prey sources that =
were important for bald eagles in the past are either diminished (e.g., =
seabirds) or have been eradicated (e.g., introduced =
ungulates). In the absence of sufficient resources, a growing bald eagle =
population on the Channel Islands could expand its =
prey base to include carrion from local pinniped colonies, exert =
predation pressure on a recovering seabird =
population, and possibly prey on endangered island foxes. =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0</p></div></div></body></html>=
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Index of Subjects