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<br />sediment is the purpose of this action, and that few if any young humpback chub in the mainstem
<br />survive through the winter months (recruitment is from LCR fish) (Valdez, personnel
<br />communication), we believe the proposed action is within the limits of incidental take allowable in
<br />this opinion and seek your concurrence on this conclusion, The BO also recommends that high
<br />flows not take place following a strong year class ofHBC, The cohort of young fish currently in
<br />the river was by Bill Persons of the AGF (personnel communication, October 7, 1997) reported to
<br />be average,
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<br />BALD EAGLE
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<br />Distribution and Abundance
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<br />The bald eagle (Accipitridae: Haliaeetus leucoCl:Phalu~) has suffered population declines from
<br />habitat loss, mortality from shooting and poisoning, and reduced reproductive success from
<br />ingestion of contaminants (U,S, Fish and WIldlife Service 1983), and it was recognized as a
<br />threatened and declining species in 1967, This species occurs throughout North America from
<br />Alaska to northern Mexico, and commonly breeds in the northern portion of its range
<br />(Stahlmaster 1987), Although bald eagles race numerous threats throughout the 48 states, they
<br />have recovered from dramatic population declines over the past several decades. Consequently,
<br />the U,S, Fish and WIldlife Service downlisted the bald eagle from endangered to threatened status
<br />(U,S, Fish and WIldlife Service 1995),
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<br />A wintering bald eagle concentration was first observed in Grand Canyon in the early 1980's and
<br />has increased dramatically since 1985 (Brown et ai" 1989, Brown and Stevens 1991. Brown and
<br />Stevens 1992), The wintering bald eagle population has been monitored since 1988, and it occurs
<br />throughout the upper half of the Grand Canyon (in Marble Canyon) and on both Lakes Powell
<br />and Mead, Density of the Grand Canyon bald eagles during the winter peak. (in late February and
<br />early March) ranged from 13 to 24 birds between Glen Canyon Dam and the Little Colorado
<br />River confluence from 1993 to 1995 (Sogge et ai" 1995), A concentration of wintering bald
<br />eagles occurs in late February at the mouth ofNankoweap Creek, where bald eagles forage on
<br />spawning rainbow trout (Brown et al" 1989, Brown 1993), Bald eagle density there ranged from
<br />6 in 1987 to 26 in 1990, and 18 bald eagles occurred at Nankoweap Creek in 1995 (Sogge et al"
<br />1995), Eagle density was correlated with trout density in the lower 0,5 Ian ofNankoweap Creek;
<br />and trout density was correlated with tributary stream water temperature. Territorial behavior,
<br />but no breeding activity, has been detected in Grand Canyon,
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<br />Life Requisit.
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<br />Bald eagles are opportunistic feeders, preying on fish, waterfowl, rabbit and road-killed game
<br />(Stahlmaster 1987), Wmtering bald eagles frequent rivers, reservoirs and lakes, including western
<br />reservoirs (Detrich 1987), and their distribution is dependent on prey availability, perch suitability,
<br />weather and human disturbance intensity (Ohmart and Sell 1980).
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