Добірка наукової літератури з теми "Thick-knees (Birds)"

The Peruvian thick-knee Burhinus superciliaris (Tschudi, 1843) is an uncommon species with highly cryptic behavior, and is thus difficult to capture and monitor. As a result, many questions remain about their basic life-history strategies and conservation status. During January and February 2009, a night-lighting technique was developed for the selective capture of Peruvian Thick-knees in southwestern Ecuador, and the molt sequence and biometrics of freeranging individuals were documented for the first time. Birds were located (24 sightings) and captured (four individuals) along 48 km of unpaved roads using a lightweight LED flashlight and a 80-cm diameter hand-held net. On average, capture success was 0.29 birds captured/session (range, 0−2) out of 0.64 attempts per session (range, 0–4) and a capture rate of 0.44 birds/attempt (n = 9 attempts). The molt progress was sequential and highly symmetrical and no simultaneous growing of feathers from the same feather tract was observed, except in secondaries. In contrast to the rectrices, primary feathers were shed from the innermost to the outermost, whereas birds seemed to have two molting centers for secondaries. The high recapture opportunities of this method allows monitoring the molt sequence, weight gain, spatial use and other life-history parameters of the Peruvian Thick-knee and possibly other small and medium-sized birds.

Avian evaporative cooling and the maintenance of body temperature (Tb) below lethal limits during heat exposure has received more attention in small species compared to larger-bodied taxa. Here, we examined thermoregulation at air temperatures (Tair) approaching and exceeding normothermic Tb in three larger birds that use gular flutter, thought to provide the basis for pronounced evaporative cooling capacity and heat tolerance. We quantified Tb, evaporative water loss (EWL) and resting metabolic rate (RMR) in the ∼170-g Namaqua sandgrouse (Pterocles namaqua), ∼430-g spotted thick-knee (Burhinus capensis) and ∼670-g spotted eagle-owl (Bubo africanus), using flow-through respirometry and a stepped Tair profile with very low chamber humidities. All three species tolerated Tair of 56–60°C before the onset of severe hyperthermia, with maximum Tb of 43.2°C, 44.3°C, and 44.2°C in sandgrouse, thick-knees and eagle-owls, respectively. Evaporative scope (i.e., maximum EWL/minimum thermoneutral EWL) was 7.4 in sandgrouse, 12.9 in thick-knees and 7.8 in eagle-owls. The relationship between RMR and Tair varied substantially among species: whereas thick-knees and eagle-owls showed clear upper critical limits of thermoneutrality above which RMR increased rapidly and linearly, sandgrouse did not. Maximum evaporative heat loss/metabolic heat production ranged from 2.8 (eagle-owls) to 5.5 (sandgrouse), the latter the highest avian value yet reported. Our data reveal some larger species with gular flutter possess pronounced evaporative cooling capacity and heat tolerance and, when taken together with published data, show thermoregulatory performance varies widely among species larger than 250 g. Our data for Namaqua sandgrouse reveal unexpectedly pronounced variation in the metabolic costs of evaporative cooling within the genus Pterocles.

Includes bibliographical references (leaves 150-161). Documents the historical distribution and subsequent decline of bush stone-curlews in South Australia, determines their current distribution and status on Kangaroo Island, their home range sizes and movements, the characteristics of foraging habitat, day roost areas and nest sites and the availability of habitat, the diet and food resources, and potential threats to the population. As a result of the findings of this survey, bush stone-curlews have been downgraded from endangered to vulnerable in South Australia.

Documents the historical distribution and subsequent decline of bush stone-curlews in South Australia, determines their current distribution and status on Kangaroo Island, their home range sizes and movements, the characteristics of foraging habitat, day roost areas and nest sites and the availability of habitat, the diet and food resources, and potential threats to the population. As a result of the findings of this survey, bush stone-curlews have been downgraded from endangered to vulnerable in South Australia.
Thesis (M.Sc.) -- University of Adelaide, Dept. of Environmental Biology, 2002.