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JONATHAN B. COHEN SARAH M. KARPANTY JAMES D. FRASER BRYAN D. WATTS BARRY R. TRUITT 《The Journal of wildlife management》2009,73(6):939-945
ABSTRACT Weekly counts of western Atlantic red knots (Calidris canutus rufa) at their Delaware Bay migration stopover site have suggested a major decline since the 1980s. We estimated red knot spring passage population size in the New Jersey Coast-Delaware Bay region (DENJ; 2004 and 2006) and Virginia (VA; 2006 and 2007), USA, by correcting weekly aerial counts for mean daily residence probability between counts in a Monte-Carlo simulation. We used daily telemetry relocations in mark-resight models to estimate mean daily residence probability. Average daily residence probability was approximately 1.0 in mid-May, 0.96–0.97 in the week of 22 May, and 0.64–0.77 after May 28 in DENJ in 2004 and 2006 and in VA in 2006. Average daily residency was approximately 0.88 in VA in 2007 from 22 May to 5 June. No birds moved from VA to DENJ in 2006 and only 2 birds (5.5%) moved in 2007. Stopover population sizes (±SE) in DENJ were 17,108 ± 1,322 in 2004 and 19,555 ± 831 in 2006, and in VA were 7,224 ± 389 in 2006 and 8,332 ± 718 in 2007, significantly greater than peak aerial counts. Years with similar peak counts had different residence probabilities; hence, adjustments for turnover should be used in the future to assess annual population changes. Our results suggest that VA can support a significant portion of this red knot subspecies during migration in at least some years. Managing red knots for recovery should entail improving our understanding of the use of other Atlantic Coast sites and protecting key coastal habitat from disturbance and development. 相似文献
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Eva M. A. Kok Jerry A. Hogan Theunis Piersma 《Ethology : formerly Zeitschrift fur Tierpsychologie》2020,126(7):681-693
Migratory shorebirds show highly organized seasonal cycles in physiological and morphological traits (body mass and composition, plumage, hormone levels, etc.), which in captivity is accompanied by restless behaviour at times when free-living birds would start migration. We introduce the idea that seasonally changing preference for habitat could motivate migrants to embark on migration and that this cognitive process could also guide them to seasonally appropriate places. We explored this by testing whether red knots (Calidris canutus), which also in captivity maintain marked circannual phenotypic rhythms, show evidence of seasonal change in preference for pictures of seasonally appropriate habitats. We first developed a method to verify whether red knots are able to memorize and discriminate contrasting pictures projected by LCD projectors. This was followed by two different experiments in which we tested for a seasonally changing preference for breeding or non-breeding habitat. When carried out during the pre-breeding season, the red knots are expected to prefer pictures of mudflats, their non-breeding habitat. At the start of the breeding season, they should prefer pictures of the tundra breeding habitat. We established that knots are able to distinguish and memorize projected images. We failed to demonstrate the predicted change in vision-based habitat preference, but for reasons of test design we do not interpret this as a strong rejection of the hypothesis. Instead, we suggest that experiments with greater numbers of individuals tested once, perhaps in combination with the provision of additional cues such as smells and sounds, will help the development of these ideas further. 相似文献
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Wan‐Juan Ke Peng He He‐Bo Peng Chi‐Yeung Choi Shou‐Dong Zhang David S. Melville Zhijun Ma 《Ibis》2019,161(4):908-914
Because migration is highly time‐constrained and migration timing varies among individuals, the responses of migrants to food shortage at a refuelling site could differ between individuals that arrive early and late at the site. To test this hypothesis, we compared the stopover decision, in terms of occurrence and length of stay (LOS), of radiotagged Great Knots Calidris tenuirostris before (2012) and after (2015) a dramatic decline in food supply at a critical spring final pre‐breeding refuelling site in the northern Yellow Sea. The probability of occurrence at the refuelling site was consistent between the two years, whereas the average LOS significantly shortened in the year of food shortage in late‐arriving individuals. This suggests migration timing intensifies the influence of food shortage in late‐arriving individuals, which might be more sensitive and vulnerable to food shortage at refuelling sites compared with early‐arriving individuals. 相似文献
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Sarah M. Karpanty Jonathan Cohen James D. Fraser Jim Berkson 《The Journal of wildlife management》2011,75(5):984-994
Horseshoe crab (Limulus polyphemus) eggs are a dietary staple of the red knot (Calidris canutus) during its spring stopover on the Delaware Bay. Numbers of knots stopping in Delaware Bay declined in the 1990s concurrent with a decline in horseshoe crabs, leading to the hypothesis that reduced horseshoe crab egg abundance limited the red knot population. Management efforts, including a seasonal harvest moratorium in the Delaware Bay, have been instituted to restore crab populations to levels of sustainable use by multiple users, including migratory birds. Our objective was to evaluate the sufficiency of horseshoe crab eggs in Delaware Bay in May–June 2004 and 2005 for knots to refuel for their migratory flight to the Arctic breeding grounds. We examined egg counts to determine if there were fewer high egg-density sites later than earlier in the day and season, as migrating birds might deplete this resource. We studied foraging rates at red knot locations to determine if foraging probes increased with time of day and season as birds depleted surface eggs by pecking, then began probing for subsurface eggs. Finally, we experimentally tested whether red knots and their competitors depleted horseshoe crab eggs. Crab egg numbers at knot foraging sites did not decline throughout the day or season in 2004. In both years, we found no evidence that knots switched from pecking to probing with increases in time since sunrise or start of the stopover. Egg numbers were similar in exclosed and accessible plots on crab nesting depressions and in areas of open intertidal zone, but were significantly lower in accessible than in exclosed plots in the wrack line. Our results indicate that horseshoe crab eggs in Delaware Bay were sufficient to support the refueling of the present-day stopover population of red knots. If an increase in the availability of crab eggs to foraging birds does not result in an increase in knot numbers, managers must prioritize mitigation of limiting factors at other historically important spring stopovers and on the poorly understood breeding and wintering grounds in addition to the Delaware Bay. © 2011 The Wildlife Society. 相似文献
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Amelia J. Macdonald Paul A. Smith Christian A. Friis James E. Lyons Yves Aubry Erica Nol 《The Journal of wildlife management》2021,85(5):932-944
Many shorebirds rely on small numbers of staging sites during long annual migrations. Numerous shorebird species are declining and understanding the importance of these staging sites is important for successful conservation. We surveyed endangered rufa red knots (Calidris canutus rufa) staging in James Bay, Ontario, Canada, during southbound migration in 2017 and 2018. We used mark-resight data and count data in an integrated Bayesian analysis to quantify migration phenology, estimate passage population size, and model the age structure of the stopover population. Many adult red knots arrived in James Bay in a single wave in early August in 2017, whereas adult red knots arrived in multiple smaller waves in July and mid-August in 2018. These waves may correspond with breeding phenology where more red knots bred successfully and arrived in one large event in 2017 and the higher number of earlier arrivals in July 2018 may have been failed breeders. We included a binomial generalized linear model in the integrated analysis to estimate that 20% and 10% of staging red knots were juveniles in 2017 and 2018, respectively. In future applications, this method could provide a metric to assess breeding performance and develop our understanding of its role in population declines. Overall, we estimated that up to 23% of the estimated rufa red knot population staged in southwestern James Bay for an average of 10–12 days. The region is a key staging site for endangered red knots and could be included in conservation planning. © 2021 The Wildlife Society. 相似文献
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Ian Scott P. Ian Mitchell Gudmundur A. Gudmundsson Mark Eaton Robin M. Ward Peter R. Evans 《Bird Study》2013,60(1):83-86
Capsule Although most birds do not need to refuel en route, many stop at Sandgerdi for a short period. 相似文献
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AbstractMigration is a biologically distinct and unique phenomenon that enables the birds to migrate twice-a-year between the breeding and wintering grounds. These movements are known as spring and autumn migration, respectively. Depending on their inherent programming, the migratory birds may fly during day or night or both. Different environmental factors such as, temperature, food, predator pressure and physiological demands of energy storage and expenditure, contribute to the pattern of migrations, day or nighttime. Since, most of them are nighttime migrants they have to make dramatic changes in their physiology and behavior to transform them from being diurnal to predominantly nocturnal. These changes result in different life history stages (LHSs) such as migration, reproduction and molt, in their annual cycle, which are regulated by endogenous circadian and circannual clocks. As a result, the birds start preparing well in advance for the approaching LHS. The present review focuses on behavioral strategies of a nocturnal migrant and understanding of the possible physiological responses to ensure successful migration. 相似文献
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中国迁徙鸣禽类的保护面对着与世界其他地区如欧洲和北美洲鸟类保护相似的挑战.迁徙鸣禽类具有复杂生活周期和很大的空间关联.迁徙过程中发生的事件对迁徙鸣禽类种群动态具有决定作用.对于鸣禽类迁徙中途停歇期的生态,比如停歇期的长短,能量的积累,生境的利用等,了解还非常有限.在中国东北部的一个鸟类迁徙停歇地对红胁蓝尾鸲（Tarsiger cyanurus）的中途停歇生态包括迁徙时间、停歇时间、能量状态和性比进行了研究.2002年秋和2003年春分别捕获了1751只和684只红胁蓝尾鸲.红胁蓝尾鸲的体重在秋季迁徙时要比在春季迁徙时重.春季雌性红胁蓝尾鸲停歇时的能量状态指数最低;而秋季的红胁蓝尾鸲比春季的红胁蓝尾鸲停歇时间更长.无论季节和性别,红胁蓝尾鸲的能量状态指数和第1次捕获的时间早晚成正相关,间接证明红胁蓝尾鸲在停歇期间能够比较快地积累能量.秋季雄性红胁蓝尾鸲日体重净增率最大.估测秋季停歇期的每日能量净增能维持红胁蓝尾鸲雌性0.6h和雄性3.1h的飞行.红胁蓝尾鸲的中途停歇生态与北美和欧洲一些迁徙鸣禽类很相似.比如,春季迁徙过境的时间和脂肪积累的变化与自然选择对雄性的要求：当食物和气候适宜时尽快到达繁殖地的假设是一致的.对迁徙中途的停歇生态研究有利于更好地了解鸟类的迁徙行为和更有效地保护迁徙鸣禽类. 相似文献
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GRACIELA ESCUDERO JUAN G. NAVEDO THEUNIS PIERSMA PETRA DE GOEIJ PIM EDELAAR 《Austral ecology》2012,37(3):355-364
The long‐distance migrant red knot (Calidris canutus ssp. rufa– Scolopacidae) alternates between the northern and southern ends of the New World, one of the longest yearly migrations of any bird and paradoxically overflying apparently suitable habitat at lower latitudes. This subspecies is sharply declining, with a major mortality event following 2000, attributed to commercial overharvesting of food resources at its Delaware Bay (USA) stop‐over site. A full understanding of this peculiar migrant requires an assessment of the foraging conditions at its southern hemisphere wintering sites. Here, for a major wintering site in Argentinean Tierra del Fuego (Río Grande), we describe and compare food abundance, diet and intake rates during January–February in 1995, 2000 and 2008. The two main prey types were the burrowing clam Darina solenoides and three species of epibenthic mussels Mytilidae. In the year 2000, food availability and intake rate were higher than those recorded at other sites used by knots anywhere else in the world, contributing to the explanation of why red knots carry out this impressive migration. Intake rate in 2008 on the two main prey types was dramatically reduced as a result of birds eating smaller prey and strongly increased human disturbance; the same year we also found a high prevalence of a digenean parasite in Darina. We suggest that during the strongly enhanced winter mortality in 2000, knots did not yet face ecological problems in their southernmost wintering area, consistent with the previous evidence that problems at northern stop‐overs negatively affected their numbers. However, in 2008 the ecological conditions at Río Grande were such that they would have facilitated a further decline, emphasizing the importance of a hemispheric approach to research and management. 相似文献
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Experimental evidence that migrants adjust usage at a stopover site to trade off food and danger 总被引：2，自引：0，他引：2
Rich habitats, intensive feeding, and large fuel deposits areassumed to improve the capability for long-distance migrationby birds but may also heighten their vulnerability or exposureto predators. Studies of habitat use by migrants have emphasizedthe importance of feeding, and relatively few studies have consideredhow migrants manage the dangers inherent in acquiring and storingfuel. Migrant western sandpipers (Calidris mauri) stop overon coastal mudflats characterized by a strong feeding–dangergradient, with both food and danger decreasing with distancefrom the shoreline. We experimentally manipulated danger byadding obstructive cover and measured sandpiper usage alongthis gradient. We compared sandpiper usage along a transectextending 100 m on either side of the obstruction with thaton matched control transects without obstructions. The droppingdensity accumulated during a low-tide period provided a sensitivemeasure of sandpiper usage. Mean usage on control transectswas 2.3 droppings/m2 and was lower by 1.5 droppings/m2 (65%)on treatment transects. Usage did not differ between controland treatment transects at the furthest distances from the obstruction,the difference increased with proximity to the obstruction,and was greater by on average 0.9 droppings/m2 on the oceanwardside (low food abundance) than on the shoreward side (high foodabundance). All these findings were predicted by danger managementtheory. Our study provides experimental evidence that migrantbirds are sensitive to danger on stopover and has implicationsfor understanding migration strategies. 相似文献
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《生态学杂志》2025,44(1)
崇明东滩近年来已成为小天鹅在我国境内一处重要的越冬地;掌握该种群的迁徙路线和模式对于候鸟的跨区域联合保护具有重要意义。2022年2—12月;对崇明东滩越冬的10只小天鹅的春季和秋季迁徙行为进行了卫星追踪;收集了1336688条定位数据。本项研究识别了崇明东滩越冬小天鹅种群向西、中、东3个方向迁徙的路线;其中新发现了一条前往俄罗斯克拉斯诺亚尔斯克边疆区的喀拉海南部沿岸繁殖的迁徙路线;并且发现小天鹅秋季迁徙后的越冬地较为广泛;包括安徽、江西、上海等地。崇明东滩越冬小天鹅春季迁徙时间、停歇次数均显著高于秋季;迁徙速度显著低于秋季;春季迁徙进程整体慢于秋季。小天鹅春季的平均迁徙距离为5805.7±648.2 km;平均迁徙时间为107.9±31.8 d;平均停歇次数为13.7±3.7次;平均飞行速度为1256.2±385.3 km·d-1;秋季的平均迁徙距离为5348.4±705.9 km;平均迁徙时间为61.3±15.3 d;平均停歇次数为6.0±1.9次;平均飞行速度1014.3±335.7 km·d-1。本研究还更新了小天鹅迁徙路线上的重要停歇地;中国境内包括内蒙古的黄河湿地以及河北张家口的滦河流域。本研究有助于更新和判断中国越冬小天鹅种群的现状和栖息地生境状况;进而采取合理的监测和管理措施保护小天鹅种群及栖息地环境。 相似文献
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Vera Brust;Heiko Schmaljohann;Ommo Hüppop; 《Journal of avian biology》2023,2023(1-2):e03004
Songbirds on migration spend a greater share of their travelling time at stopover sites in order to rest, recover and refuel compared to actively flying. In the German Bight of the North Sea, two subspecies of the northern wheatear split travelling routes, with Greenlandic/Icelandic breeders (subspecies leucorhoa) facing a long over-sea flight and Scandinavian breeding birds (subspecies oenanthe) travelling further roughly along the coast. We used automated radio-telemetry in spring to show that leucorhoa birds stayed significantly longer at a coastal stopover site and clearly selected for favourable weather, especially easterly winds, when resuming flights. Conditions for departures of individuals from the subspecies oenanthe were less obvious. They were more likely to depart on nights with southerly winds, often along with rising air temperatures, while air pressure dropped. Individuals of subspecies leucorhoa thus wait for optimal flying conditions to resume for longer flights, while oenanthe birds, with shorter distances ahead, seem to optimise time by leaving the stopover site more quickly. Our dataset thus confirms that songbirds optimise stopover based on their (sub)species-specific migration patterns. 相似文献
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The conservation of migratory songbirds in China faces challenges similar to those in other parts of the world such as Europe and North America. Migratory songbirds have a complex life history and are associated with large spatial scale. Events that occur during migration play a vital role in determining population status. Little is known about the stopover behavior of migratory songbirds in China during their passage, including stopover duration, energetic condition (e.g., the amount of fat stores), and the habitat of these birds. We investigated migration timing, stopover duration, change of energetic condition and sex-related variations among Red-flanked Bush Robins (Tarsiger cyanurus) at a stopover site in Northeast China. A total of 1 751 Red-flanked Bush Robins were captured in the fall of 2002, with further 684 captured in the spring of 2003. The body mass of the fall birds was higher than that of the spring ones. The condition index (i.e., body mass adjusted for body size) was lowest among spring females. Birds were more likely to stay longer in fall than in spring. We detected a positive relationship between the time of initial capture and condition index regardless of season or sex, suggesting that the birds were able to replenish energy stores. The net daily mass gain was the highest among males in the fall (3% of body mass). The net daily mass gain would sustain a flight of 0.6 hours for females and 3.1 hours for males in the fall. The stopover biology of Red-flanked Bush Robins is similar to that of some migratory songbirds in Europe and North America. For example, the spring passage time and fat store variation between the sexes concurs with the hypothesis that males are selected to arrive at their breeding grounds as early as food resources or climatic conditions are adequate in the spring. Further research on stopover ecology is urgently required in China to achieve a better understanding of migratory behavior and ensure the conservation of these migratory songbirds. 相似文献
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中国迁徙鸣禽类的保护面对着与世界其他地区如欧洲和北美洲鸟类保护相似的挑战。迁徙鸣禽类具有复杂生活周期和很大的空间关联。迁徙过程中发生的事件对迁徙鸣禽类种群动态具有决定作用。对于鸣禽类迁徙中途停歇期的生态,比如停歇期的长短,能量的积累,生境的利用等,了解还非常有限。在中国东北部的一个鸟类迁徙停歇地对红胁蓝尾鸲(Tarsiger cyanurus)的中途停歇生态包括迁徙时间、停歇时间、能量状态和性比进行了研究。2002年秋和2003年春分别捕获了1751只和684只红胁蓝尾鸲。红胁蓝尾鸲的体重在秋季迁徙时要比在春季迁徙时重。春季雌性红胁蓝尾鸲停歇时的能量状态指数最低; 而秋季的红胁蓝尾鸲比春季的红胁蓝尾鸲停歇时间更长。无论季节和性别,红胁蓝尾鸲的能量状态指数和第1次捕获的时间早晚成正相关, 间接证明红胁蓝尾鸲在停歇期间能够比较快地积累能量。秋季雄性红胁蓝尾鸲日体重净增率最大。估测秋季停歇期的每日能量净增能维持红胁蓝尾鸲雌性0.6h和雄性3.1h的飞行。红胁蓝尾鸲的中途停歇生态与北美和欧洲一些迁徙鸣禽类很相似。比如,春季迁徙过境的时间和脂肪积累的变化与自然选择对雄性的要求：当食物和气候适宜时尽快到达繁殖地的假设是一致的。对迁徙中途的停歇生态研究有利于更好地了解鸟类的迁徙行为和更有效地保护迁徙鸣禽类。 相似文献
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Fawen Qian Heqi Wu Libo Gao Huige Zhang Fengshan Li Xingyao Zhong Xiaojun Yang Guangmei Zheng 《Journal of Field Ornithology》2009,80(1):19-26
ABSTRACT. Because their breeding and wintering areas are in remote locations, little is known about the biology of Black-necked Cranes ( Grus nigricollis ), including their migratory behavior. Using satellite telemetry, we monitored the migration of Black-necked Cranes ( N = 6) in China to determine migration routes and the location of stopover sites. From 2005 to 2007, four cranes were tracked during two spring migrations and one fall migration, one was tracked during one spring and one fall migration, and one was tracked during one spring migration. On average, the cranes made seven flights over a 5-d period to migrate 651 km to breeding areas in the spring. In the fall, birds averaged six flights in 5 d to migrate 694 km. The routes traveled by cranes during spring and autumn migration were similar. Both the migration distances and duration of migration are the shortest reported for any crane species to date. Most stopover sites were in areas along rivers and close to wetlands in the Daliang Mountains and the Ruoergai Plateau. Conservation measures are needed to reduce habitat loss (wetland and pasture) in the Daliang Mountains and establish a reserve for stopover sites in the Ruoergai marshes, such as Longriba and Bai River in Hongyuan County. 相似文献
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时间是限制鸟类迁徙活动的关键因素之一。鸫科候鸟两性不同的身体特征以及成幼不同的换羽模式可能使它们的秋季迁徙停歇模式出现较大的种内差异。于2021年和2022年秋季,在福建省明溪县开展鸫鸟环志,共环志了643只鸫科候鸟,包括白眉鸫 (Turdus obscurus)(364只)、灰背鸫 (T. hortulorum)(161只)、乌灰鸫 (T. cardis)(59只)、虎斑地鸫 (Zoothera aurea)(15只), 白腹鸫 (T. pallidus)(20只), 白眉地鸫 (Geokichla sibirica)(3只) 和斑鸫 (T. eunomus)(1只)。比较了三种优势鸫的迁徙时序和身体特征的种内和种间差异,分析了它们的迁徙动态,以及翅长和脂肪级分布。结果显示,白眉鸫和乌灰鸫成鸟的抵达时间分别比幼鸟早2天和3天。三种鸫的抵达时间都没有性别差异。白眉鸫的抵达时间比灰背鸫和乌灰鸫分别晚3天和2天。白眉鸫成鸟的翅长显著长于幼鸟,而灰背鸫和乌灰鸫的翅长没有显著差异,拥有更长的翅膀可能是白眉鸫成鸟比幼鸟先到的原因。白眉鸫和灰背鸫的翅尖指数随到达时间呈显著下降的趋势,脂肪含量则随到达时间显著上升,表明这两种鸫存在迁徙距离较长的个体更早到达,并且脂肪水平较低的规律。三种鸫的迁徙高峰期均少于10天,平均脂肪级均小于2级,表明鸫科候鸟可能采取了能量最小对策,并在较短时间内集中通过明溪。明溪县是鸫科候鸟重要的中途停歇地。应做好栖息地保护工作,为鸫科候鸟提供高质量的栖息环境。在鸫科候鸟的迁徙高峰期间,应尽可能减少人为干扰,以免影响鸫类的停歇活动。 相似文献