5 research outputs found
Breeding Ecology of Birds at Teshekpuk Lake: A Key Habitat Site on the Arctic Coastal Plain of Alaska
The Teshekpuk Lake Special Area in the National Petroleum Reserve â Alaska (NPR-A) currently has no long-term protection from oil development. In this study, we provide novel information on nest density, productivity, and habitat use at Teshekpuk relative to a developed oilfield site at Prudhoe Bay, Alaska, to assess the importance of Teshekpuk for tundra-nesting birds and to provide recommendations regarding potential oil development. Mean annual nest density of all bird species combined was significantly higher at Teshekpuk than at Prudhoe Bay and was higher than any of five other sites with comparable data on the Alaskan Arctic Coastal Plain. Nest densities were significantly higher at Teshekpuk than at Prudhoe Bay for Lapland longspurs (Calcarius lapponicus) and long-billed dowitchers (Limnodromus scolopaceus), although those for semipalmated sandpipers (Calidris pusilla) were higher at Prudhoe Bay. Total shorebird nest densities at Teshekpuk were among the highest of any sites in the region. At Teshekpuk, shorebirds nested preferentially in wet and emergent habitats, including flooded low-center polygons, non-patterned tundra, and Carex aquatilis-dominated habitats. Therefore, we recommend that future oil infrastructure placement in this region avoid these habitats. Using data collected at Teshekpuk and Prudhoe Bay from 2005 to 2008, we modeled nest survivorship for 11 shorebird species and for Lapland longspurs. For longspurs, the best-supported models based on AICc values indicated that nest survival was always higher at Teshekpuk, but it was also higher elsewhere in years of high lemming abundance and later in the nesting season. For shorebirds, the best-supported models indicated that nest survivorship was highly variable among years and sites. Uniparental-nesting shorebirds had lower nest survivorship shortly after nest initiation followed by a rapid increase, while biparental survivorship was consistently high throughout the nest lifetime. We recommend that disturbances to nesting habitat be minimized during early June, when vulnerability to nest failure is higher. Because of their high importance to Arctic breeding birds, we recommend that areas within the Teshekpuk Lake Special Area, including our study area and those that are currently under 10-year deferral, be considered for permanent protection.La zone spĂ©ciale du lac Teshekpuk situĂ©e dans la rĂ©serve nationale de pĂ©trole de lâAlaska (NPR-A) nâest dotĂ©e dâaucune protection Ă long terme en matiĂšre de mise en valeur pĂ©troliĂšre. Dans la prĂ©sente Ă©tude, nous fournissons de nouveaux renseignements sur la densitĂ© des nids, la productivitĂ© et lâutilisation de lâhabitat Ă Teshekpuk Ă la lumiĂšre dâun chantier de mise en valeur pĂ©troliĂšre Ă la baie Prudhoe, en Alaska et ce, dans le but dâĂ©valuer lâimportance de Teshekpuk pour les oiseaux qui nichent dans la toundra ainsi que de fournir des recommandations en matiĂšre de mise en valeur pĂ©troliĂšre future. La densitĂ© moyenne annuelle des nids de toutes les espĂšces dâoiseaux prises ensemble Ă©tait considĂ©rablement supĂ©rieure Ă Teshekpuk quâĂ la baie Prudhoe et Ă©tait plus Ă©levĂ©e que dans nâimporte quel des cinq autres sites aux donnĂ©es comparables sur la plaine cĂŽtiĂšre arctique de lâAlaska. La densitĂ© des nids Ă©tait considĂ©rablement supĂ©rieure Ă Teshekpuk quâĂ la baie Prudhoe dans le cas du bruant lapon (Calcarius lapponicus) et du bĂ©casseau Ă long bec (Limnodromus scolopaceus), tandis que les densitĂ©s du bĂ©casseau semipalmĂ© (Calidris pusilla) Ă©taient plus Ă©levĂ©es Ă la baie Prudhoe. Les densitĂ©s totales de nids dâoiseaux de rivage Ă Teshekpuk comptaient parmi les densitĂ©s les plus Ă©levĂ©es de nâimporte quel des sites de la rĂ©gion. Ă Teshekpuk, les oiseaux de rivage nichaient, de prĂ©fĂ©rence, dans des habitats humides et Ă©mergents, ce qui comprend les polygones concaves inondĂ©s et la toundra non rĂ©ticulĂ©e de mĂȘme que les habitats dominĂ©s par le Carex aquatilis. Nous recommandons donc que lâemplacement dâinfrastructures pĂ©troliĂšres futures dans cette rĂ©gion Ă©vite ces habitats. Ă lâaide de donnĂ©es recueillies Ă Teshekpuk et Ă la baie Prudhoe de 2005 Ă 2008, nous avons modĂ©lisĂ© la prĂ©somption de survie en nid de 11 espĂšces dâoiseaux de rivage et des bruants lapons. Dans le cas des bruants lapons, les modĂšles les mieux soutenus dâaprĂšs les valeurs AICc laissent entrevoir que la survie en nid Ă©tait constamment supĂ©rieure Ă Teshekpuk, mais quâelle Ă©tait Ă©galement plus Ă©levĂ©e ailleurs pendant les annĂ©es de grande abondance de lemmings de mĂȘme quâĂ une pĂ©riode plus tardive de la saison de nidification. Dans le cas des oiseaux de rivage, les modĂšles les mieux soutenus indiquent que la survie en nid varie beaucoup dâune annĂ©e Ă lâautre et dâun emplacement Ă lâautre. Les oiseaux de rivage en mode de nidification monoparental affichaient un taux de survie en nid moins Ă©levĂ© peu aprĂšs lâinitiation du nid, ce qui Ă©tait suivi dâune augmentation rapide, tandis que le taux de survie des oiseaux en mode de nidification biparental Ă©tait constamment Ă©levĂ© pendant toute la durĂ©e dâexistence du nid. Nous recommandons donc que les perturbations Ă lâhabitat de nidification soient rĂ©duites au minimum au dĂ©but de juin car câest Ă ce moment-lĂ que la nidification est plus vulnĂ©rable. Compte tenu de leur grande importance pour les oiseaux nicheurs de lâArctique, nous recommandons que les aires faisant partie de la zone spĂ©ciale du lac Teshekpuk, ce qui comprend lâaire visĂ©e par notre Ă©tude et les aires faisant couramment lâobjet dâun report de 10 ans, soient considĂ©rĂ©es Ă titre de protection permanente
POTENTIAL EFFECTS OF CLIMATE CHANGE ON ELEVATIONAL DISTRIBUTIONS OF TROPICAL BIRDS IN SOUTHEAST ASIA
Environmental conditions during the neonatal period can affect the growth, physiology, behavior, and immune function of birds. In many avian studies the nestling environment includes investigator handling of young, which may be stressful. While neonatal handling is known to affect the adult phenotype in rats, the effects of handling on development have rarely been examined in wild birds. We examined the effect of short, repeated periods of neonatal handling on avian growth and immune system development. We subjected American Kestrels (Falco sparverius) and European Starlings (Sturnus vulgaris) to 15 min of daily investigator handling throughout the nestling period, while controls remained undisturbed. Immediately prior to fledging we assessed cutaneous immunity, humoral immunity, mass, and degree of fluctuating asymmetry. Daily handling did not significantly affect any of these measurements. We also addressed the possibility that treatment differences would appear only when birds were challenged with a more substantial stressor by bringing birds into captivity for 24 hr. Captivity did not affect mass, but significantly lowered the cutaneous immune response, although this was independent of treatment. Therefore, brief periods of investigator handling did not appear to affect immune or morphological development in these species, whereas 24 hr of captivity resulted in suppressed cutaneous immune responses