排序方式: 共有115条查询结果,搜索用时 15 毫秒
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Following recovery and successful rehabilitation, a young Steppe Eagle Aquila nipalensis was tagged with a 45 g GPS satellite transmitter to track its migration and identify potential wintering and summering areas of the species passing through the United Arab Emirates (UAE). The study is part of a larger study on understanding migration of important birds of prey species from the UAE. The satellite-tagged Steppe Eagle was released near the town of Al Ain, UAE on 5 January 2009 and was tracked until 6 November 2010. Two complete spring and autumn migrations were tracked in addition to its onward autumn migration from the UAE. The tagged eagle continued its autumn migration from its release site and reached Yemen after stopovers in Saudi Arabia. Unlike other Steppe Eagles, the bird did not cross the strait of Bab-al-Mandeb and wintered in the area before undertaking its first spring migration. In the second spring migration in 2010, the bird migrated along the Suez–Eilat route and demonstrated a loop migration. The bird spent the summer on the steppes in Kazakhstan, with marked differences in the home ranges between 2009 and 2010, whereas wintering areas used in 2009 and 2010 in Tanzania were overlapping. 相似文献
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G. J. Broekhuysen 《Ostrich》2013,84(1):57-66
A fragmentary skull of a small passerine from the mid-Holocene organic-rich deposits at Florisbad, South Africa, shows a pattern of distinctive characters that allows its identification as a Cercomela chat. It resembles most closely the Familiar Chat C. familiaris and Karoo Chat C. schlegelii, which are still part of the avifauna in this part of South Africa. Furthermore, the significance of several characters of the skull for hypotheses on the phylogeny of Muscicapoidea in general, and Saxicolinae in particular, is discussed. 相似文献
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山西芦芽山褐马鸡越冬栖息地选择的多尺度研究 总被引:15,自引:0,他引:15
1998~2000年在山西芦芽山自然保护区对褐马鸡的越冬栖息地选择进行了研究。采用4种空间尺度(10m、100m、300m和距离尺度),对影响褐马鸡越冬栖息地选择的主要因子进行了深入分析,并建立了褐马鸡越冬栖息地选择的逻辑斯谛回归模型。在300m尺度上.活动点和非活动点的生境类型有针叶林、针阔混交林、灌木林和草丛等。活动点周围针叶林面积显著高于非活动点(F=-3.116,P=0.002),虽然针阔混交林在两者中的面积比例都较小,但活动点周围针阔混交林的面积明显地低于非活动点(F=-2.255,P=0.024).在灌木林和草丛的面积上两者无显著差异。这表明褐马鸡在300m尺度上喜欢活动于针叶林较多的地域,由于冬季针阔混交林不如针叶林能提供很好的隐蔽条件,褐马鸡避免选择针阔混交林;在100m尺度上,活动点和非活动点的生境类型有针叶林、针阔混交林和草丛,无灌木林生境,活动点的针叶林面积明显地高于非活动点(F=-2.931,P=0.003)。这表明褐马鸡在100m尺度上虽然倾向于选择针叶林,但对其它类型的生境如针阔混交林和草丛是可以利用的,这可能与其广泛取食活动有关。褐马鸡大尺度上的隐蔽条件满足以后,在小尺度上主要是为了获取更为丰富的食物。在距离尺度上活动点距居民点的距离、距道路的距离显著大于非活动点(F=15.621;6.048,P=0.000;0.018)。通过逐步逻辑斯谛回归分析,发现距灌草丛的距离、距居民点的距离、100m范围内针叶林的面积、树高以及食物的丰盛度是冬季褐马鸡栖息地选择的重要因子。以另外一个研究地收集的数据对所建立的栖息地选择模型的可靠程度进行了检验,结果表明该模型能有效地对褐马鸡的越冬栖息地进行预测。 相似文献
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Kasper Thorup 《Journal of Biogeography》2006,33(7):1166-1171
Aim It is generally believed that the migration programme constrains the dispersal and hence range sizes of migratory bird species. This conclusion is based on analyses of breeding ranges of migratory versus non-migratory (resident) terrestrial bird species, and rests on the assumption that there are no ecological or evolutionary constraints on extending the non-breeding range. To investigate this assumption, the abilities of migrant and resident terrestrial species to colonize new wintering areas were compared.
Location Three major wintering regions of long-distance migrants: South America, sub-Saharan Africa and the Indian Subcontinent.
Methods It was determined whether the relative numbers of residents and short- and long-distance migrants were the same in those species that have dispersed to a novel wintering region as in the source species pools.
Results At the species level, long-distance migratory species are more likely to have non-breeding ranges that include more than one of the above regions than resident species. This indicates that the dispersal of migratory species is less constrained than that of resident species. The pattern holds irrespective of the inclusion or exclusion of species associated with coastal, freshwater and wetland habitats, and also holds for ecological groups such as aerial feeders. The pattern is most pronounced between the regions separated by the strongest dispersal barriers (South America and sub-Saharan Africa).
Main conclusions It is unlikely that the migration programme per se constrains dispersal, but rather that difficulties in establishing new non-breeding areas prevent range expansions in migrant species. 相似文献
Location Three major wintering regions of long-distance migrants: South America, sub-Saharan Africa and the Indian Subcontinent.
Methods It was determined whether the relative numbers of residents and short- and long-distance migrants were the same in those species that have dispersed to a novel wintering region as in the source species pools.
Results At the species level, long-distance migratory species are more likely to have non-breeding ranges that include more than one of the above regions than resident species. This indicates that the dispersal of migratory species is less constrained than that of resident species. The pattern holds irrespective of the inclusion or exclusion of species associated with coastal, freshwater and wetland habitats, and also holds for ecological groups such as aerial feeders. The pattern is most pronounced between the regions separated by the strongest dispersal barriers (South America and sub-Saharan Africa).
Main conclusions It is unlikely that the migration programme per se constrains dispersal, but rather that difficulties in establishing new non-breeding areas prevent range expansions in migrant species. 相似文献
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Aurore Ponchon Thomas Cornulier April Hedd Jos Pedro Granadeiro Paulo Catry 《Ecology and evolution》2019,9(15):8702-8713
Pelagic seabirds breeding at high latitudes generally split their annual cycle between reproduction, migration, and wintering. During the breeding season, they are constrained in their foraging range due to reproduction while during winter months, and they often undertake long‐distance migrations. Black‐browed albatrosses (Thalassarche melanophris) nesting in the Falkland archipelago remain within 700 km from their breeding colonies all year‐round and can therefore be considered as resident. Accordingly, at‐sea activity patterns are expected to be adjusted to the absence of migration. Likewise, breeding performance is expected to affect foraging, flying, and floating activities, as failed individuals are relieved from reproduction earlier than successful ones. Using geolocators coupled with a saltwater immersion sensor, we detailed the spatial distribution and temporal dynamics of at‐sea activity budgets of successful and failed breeding black‐browed albatrosses nesting in New Island, Falklands archipelago, over the breeding and subsequent nonbreeding season. The 90% monthly kernel distribution of failed and successful breeders suggested no spatial segregation. Both groups followed the same dynamics of foraging effort both during daylight and darkness all year, except during chick‐rearing, when successful breeders foraged more intensively. Failed and successful breeders started decreasing flying activities during daylight at the same time, 2–3 weeks after hatching period, but failed breeders reached their maximum floating activity during late chick‐rearing, 2 months before successful breeders. Moon cycle had a significant effect on activity budgets during darkness, with individuals generally more active during full moon. Our results highlight that successful breeders buffer potential reproductive costs during the nonbreeding season, and this provides a better understanding of how individuals adjust their spatial distribution and activity budgets according to their breeding performance in absence of migration. 相似文献
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Gschweng M Kalko EK Querner U Fiedler W Berthold P 《Proceedings. Biological sciences / The Royal Society》2008,275(1653):2887-2896
Eleonora's falcon (Falco eleonorae) is a rare raptor species that delays its breeding period until late summer to feed its young with passerines at the peak of autumn migration. Since the 1950s, this slender winged falcon has been believed to migrate along a historical route via the Red Sea to its main wintering area in Madagascar. In our study, we used satellite telemetry to investigate the real migration route of Eleonora's falcons and found that the species displayed a highly individual migration pattern. Furthermore, juvenile falcons migrated via West Africa to Madagascar and two juveniles could be tracked during spring migration and to their summering areas in East and West Africa. As juveniles migrated independently of adults, we discuss inherited navigation strategies forming part of a complex navigation system. We propose the idea of an orientation mechanism that naive falcons could apply during their long-distance migration towards their faraway wintering area located in the open ocean. 相似文献
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Does wintering north or south of the Sahara correlate with timing and breeding performance in black‐tailed godwits? 下载免费PDF全文
Rosemarie Kentie Rocío Marquez‐Ferrando Jordi Figuerola Laura Gangoso Jos C.E.W. Hooijmeijer A. H. Jelle Loonstra Frédéric Robin Mathieu Sarasa Nathan Senner Haije Valkema Mo A. Verhoeven Theunis Piersma 《Ecology and evolution》2017,7(8):2812-2820
Migrating long distances requires time and energy, and may interact with an individual's performance during breeding. These seasonal interactions in migratory animals are best described in populations with disjunct nonbreeding distributions. The black‐tailed godwit (Limosa limosa limosa), which breeds in agricultural grasslands in Western Europe, has such a disjunct nonbreeding distribution: The majority spend the nonbreeding season in West Africa, while a growing number winters north of the Sahara on the Iberian Peninsula. To test whether crossing the Sahara has an effect on breeding season phenology and reproductive parameters, we examined differences in the timing of arrival, breeding habitat quality, lay date, egg volume, and daily nest survival among godwits (154 females and 157 males), individually marked in a breeding area in the Netherlands for which wintering destination was known on the basis of resightings. We also examined whether individual repeatability in arrival date differed between birds wintering north or south of the Sahara. Contrary to expectation, godwits wintering south of the Sahara arrived two days earlier and initiated their clutch six days earlier than godwits wintering north of the Sahara. Arrival date was equally repeatable for both groups, and egg volume larger in birds wintering north of the Sahara. Despite these differences, we found no association between wintering location and the quality of breeding habitat or nest survival. This suggests that the crossing of an important ecological barrier and doubling of the migration distance, twice a year, do not have clear negative reproductive consequences for some long‐distance migrants. 相似文献