Boreal Birds of North America: A Hemispheric View of Their Conservation Links and Significance (Studies in Avian Biology)
Jeffrey V. Wells
Language: English
Pages: 160
ISBN: 0520271009
Format: PDF / Kindle (mobi) / ePub
shifting states or gradual change? Ambio 33:361–365. Christensen, T. K. 1999. Effects of cohort and individual variation in duckling body condition on survival and recruitment in the Common Eider Somateria mollissima. Journal of Avian Biology 30:302–308. Corcoran, R. M., J. R. Lovvorn, M. R. Bertram, and M. T. Vivion. 2007. Lesser Scaup nest success and duckling survival on the Yukon Flats, Alaska. Journal of Wildlife Management 71:127–134. STUDIES IN AVIAN BIOLOGY NO. 41 Wells 8/24/11
(Jessen 1981), but in the past three decades, many areas of the NBF in western North America have warmed more rapidly than any other region on earth (Serreze et al. 2000). Sea ducks are the most northerly nesting of the ducks (Goudie et al. 1994), and climateinduced change, including alteration of wetlands (Smol and Douglas 2007), has been predicted to have the greatest effect on northern ecosystems (Soja et al. 2007). Migratory birds such as the Surf Scoter occupy the NBF for 3–4 months of the
Palm Warbler Dendroica palmarum palmarum “Yellow” Palm Warbler Dendroica p. hypochrysea 4,417 Bay-breasted Warbler Dendroica castanea 9,056 Blackpoll Warbler Dendroica striata 37,739 Black-and-white Warbler Mniotilta varia 22,797 Northern Waterthrush Seiurus noveboracensis 24,367 Connecticut Warbler Oporornis agilis 2,374 Mourning Warbler Oporornis philadelphia 7,800 2,842 195 10,420 187 1 72 83 40,378 2,554 228,791 10 17,010 APPENDIX 6.1 (continued)
such as the Common Loon (Gavia immer) (Burgess and Meyer 2008; Evers et al. 2008), only recently has the availability of MeHg in wetland birds been identified as a major threat (Schwarzbach et al. 2006). Concentrations deemed to have adverse effects on egg hatchability, based on Heinz et al. (2008), have been documented for wild breeding populations of Icterids, including the Redwinged Blackbird (Agelaius phoeniceus) (Evers et al. 2005) and Rusty Blackbird (Evers, pers. comm.). Current sampling
differences in the availability of small trees rather than geographic variation in preference. Winter Habitat Characteristics As in other temperate zone blackbirds, Rusty Blackbirds have two distinct habitat needs during the non-breeding season: foraging areas and roosting sites. In terms of foraging areas, Rusty Blackbirds winter primarily in wet bottomland hardwood forests (Avery 1995). They are common in areas of continuous semi-flooded forest, but in drier areas they can be seen in