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1.
2015年3月和2016年4月,分别对黄河中上游迁徙期的水鸟资源与大天鹅(Cygnus cygnus)的栖息地进行了调查,旨在掌握黄河中上游春季迁徙期水鸟的资源现状以及大天鹅的活动特征。根据黄河湿地植被和水系分布状况,沿着黄河自西部磴口县至东部土默特右旗进行调查。采用核密度分析法(KDE)计算了大天鹅日间和夜间活动区面积,以及增强型植被指数(EVI)分析了活动区内的栖息地特征。共记录到37种25671只水鸟,其中雁鸭类占水鸟总数的89.6%,特别是大天鹅和小天鹅(C.columbianus)数量较多。内蒙古段黄河是大天鹅春季迁徙重要停歇地之一,大天鹅在此停留时间长((27.23±8.96)d,n=56),日间栖息地和夜宿地基本相似。90%以内区域的EVI值均较低,50%活动区域明显低于50%~90%区域。黄河及农田蓄水而成的河漫滩为大天鹅提供了充足的食物,栖息地隐蔽性较强,适宜大天鹅等水鸟在此长期栖息。  相似文献   

2.
中途停歇地是候鸟重要的能量补给地及休息站,对其顺利完成迁徙有着重要作用。为了解灰鹤(Grus grus)迁徙途中的停歇模式,于2013年和2015年冬季,采用卫星跟踪技术在贵州草海保护区成功跟踪了4只灰鹤。结果显示,其中3只灰鹤在宁夏中卫市境内的黄河和清水河流域湿地停歇,表明该地区为灰鹤迁徙时的重要停歇地。春季迁徙时,灰鹤在2月初至3月初到达中卫,平均停留(24.5?6.7)d(15~30 d,n=4),2月底至3月底迁离;秋季迁徙时,10月末至11月初到达,平均停留(32.0?4.2)d(29~35 d,n=2),至11月底迁离。停留期间主要的活动范围为中宁县境内的长山头水库、黄河河心岛及同心县境内的清水河周边区域。2017年3月18日,采用夜栖地直接计数法进行实地调查,共发现灰鹤636只,其日间活动范围和卫星跟踪结果类似。此次发现的灰鹤停歇地均未纳入自然保护体系,建议当地林业部门在灰鹤迁徙期间加强管理,可适当投食,以减少灰鹤误食耕地中经农药包衣处理的玉米(Zea mays)种子造成的死亡。  相似文献   

3.
云南大山包越冬黑颈鹤迁徙路线的卫星跟踪   总被引:6,自引:0,他引:6  
2005年2月26日和3月1日在云南省昭通大山包黑颈鹤国家级自然保护区,分别为4只越冬黑颈鹤佩戴卫星信号发射器(PTTs),跟踪研究其迁徙路线和迁徙停歇地。2005年春季迁徙中,有2只跟踪黑颈鹤到达繁殖地,其中1只黑颈鹤在2005年11月和2006年3月分别完成从繁殖地返回越冬地和从越冬地再次到达繁殖地的迁徙过程。2只春季迁徙黑颈鹤的迁徙路线大致相同——沿着长江上游金沙江、大渡河一直向北到达黄河上游白河及黑河沿岸若尔盖湿地内。春季迁徙过程中,途中停歇3—4次,总迁徙距离是674—713km,迁徙全程所用时间3—4天。秋季迁徙全程所用时间8天。在4个PTTs工作期间,共确定有13个黑颈鹤迁徙停歇地,其中11个停歇地在河流滩地;其他2个停歇地在高山湖泊附近。总体上,黑颈鹤一般选择海拔在1900m以上湖泊、河流等湿地内,距离耕地较近且人、畜干扰较少的栖息地停歇。  相似文献   

4.
福建省黑脸琵鹭的分布及栖息地现状   总被引:2,自引:0,他引:2  
2003年3月~2006年4月,对福建省海岸湿地的黑脸琵鹭(Platalea minor)及其栖息地进行了研究。在福建省越冬的黑脸琵鹭约60~90只,每年迁徙停歇的种群数量在80只以上,黑脸琵鹭主要选择河口的滩涂湿地作为越冬和迁徙停歇地。栖息地的丧失和破坏是其面临的最大生存威胁。实施湿地保护和可持续利用工程,并帮助当地政府和民众寻找到发挥湿地更高经济效益的产业是保护黑脸琵鹭栖息地的重要途径。  相似文献   

5.
2005年2月26日和3月1日在云南省昭通大山包黑颈鹤国家级自然保护区,分别为4只越冬黑颈鹤佩戴卫星信号发射器(PTTs),跟踪研究其迁徙路线和迁徙停歇地。2005年春季迁徙中,有2只跟踪黑颈鹤到达繁殖地,其中1只黑颈鹤在2005年11月和2006年3月分别完成从繁殖地返回越冬地和从越冬地再次到达繁殖地的迁徙过程。2只春季迁徙黑颈鹤的迁徙路线大致相同——沿着长江上游金沙江、大渡河一直向北到达黄河上游白河及黑河沿岸若尔盖湿地内。春季迁徙过程中,途中停歇3—4次,总迁徙距离是674—713 km,迁徙全程所用时间3—4天。秋季迁徙全程所用时间8天。在4个PTTs工作期间,共确定有13个黑颈鹤迁徙停歇地,其中11个停歇地在河流滩地;其他2个停歇地在高山湖泊附近。总体上,黑颈鹤一般选择海拔在1 900 m以上湖泊、河流等湿地内,距离耕地较近且人、畜干扰较少的栖息地停歇。  相似文献   

6.
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   

7.
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   

8.
卫星跟踪技术在候鸟迁徙研究中的应用   总被引:5,自引:0,他引:5  
自20世纪80年代末期应用基于Argos系统的卫星跟踪技术开展候鸟迁徙研究以来,鸟类学家取得了许多利用传统鸟类迁徙研究方法所无法取得的成果。但在中国,卫星跟踪技术在鸟类迁徙中的应用尚属空白。作者利用参与中国首次应用卫星跟踪技术跟踪候鸟迁徙研究之机,对该技术用于候鸟迁徙研究的技术平台、主要内容和未来研究进行了综述和展望。利用卫星跟踪技术开展的主要研究内容有:揭示迁徙路线和重要停歇地点;寻找新繁殖地和越冬地;利用卫星数据对栖息地及其利用进行评价;探讨鸟类的迁徙策略。期望该技术能够成为中国濒危鸟类保护的有效方法,并尽快得到应用。  相似文献   

9.
迁徙鸟类中途停歇期的生理生态学研究   总被引:5,自引:3,他引:2  
马志军  王勇  陈家宽 《生态学报》2005,25(11):3067-6075
大多数候鸟的迁徙活动由迁徙飞行和中途停歇两个部分组成。在迁徙过程中,鸟类要多次交替经历消耗能量的飞行阶段和积累能量的中途停歇阶段。从鸟类在中途停歇时期的能量积累速度、体重变化模式以及迁徙飞行中的禁食或食物限制、食物种类的改变、中途停歇的能量快速积累过程对消化器官的影响等方面,对目前迁徙鸟类的生理生态学研究成果进行回顾,并提出有待解决的问题及今后的研究方向。  相似文献   

10.
追踪候鸟的迁徙活动是全面认识其生活史年周期的重要途径。中杓鹬(Numeniusphaeopus)在全球广泛分布,但在东亚-澳大利西亚候鸟迁飞区的迁徙活动一直缺乏追踪研究。2018年2月,在澳大利亚西北部的布鲁姆为捕捉到的中杓鹬成鸟佩戴平台发射终端或全球定位系统-全球移动通讯系统追踪器,以确定其迁徙日程、迁徙路线以及迁徙停歇地和繁殖地的地理位置。我们从成功追踪的7只个体获取了6 378条精度高于1 km的位点数据。分析结果表明,在春季,中杓鹬的迁徙时长为(36±4)d,其间在1~3个迁徙停歇地的停留日期为(23±2)d,从越冬地到繁殖地的迁徙距离为(9 795±346)km(n=7)。追踪的中杓鹬在俄罗斯东部和中部区域繁殖,不同个体的繁殖地纬度相近而经度范围较广。在秋季,中杓鹬的迁徙时长为(90±27)d,相比春季迁徙时长更长;其间,在2~4个迁徙停歇地停留(79±29)d,从繁殖地到越冬地的迁徙距离为(10 101±520)km(n=5)。无论在春季还是秋季迁徙,迁徙停歇地广泛分布于东亚、东南亚沿海及内陆区域。大部分个体春季和秋季的迁徙路线相近,成功追踪的个体均在秋季返回了上一年的越冬地,这表明中杓鹬对越冬地具有很高的忠诚度。  相似文献   

11.
2015年初,黄河三门峡库区发生了大天鹅(Cygnus cygnus)等野鸟感染高致病性禽流感病毒的疫情,我们通过对三门峡大天鹅越冬种群的监测和环志回收的分析,了解大天鹅的越冬种群现状和活动状况,希望研究结果有助于我国对大天鹅种群的保护。调查表明,近些年来大天鹅越冬种群数量呈上升趋势,特别是三门峡天鹅湖由2010年410只增加到2014年6 317只,大天鹅种群数量在12月中旬至翌年1月达到高峰,2月下旬陆续离开,至3月下旬全部北迁。根据彩色颈环标记的回收结果,大天鹅对三门峡库区作为越冬地的选择是较为稳定的,不同个体在库区内的各地点之间还存在游荡行为,此外,还观察到带有彩色颈环的119只个体,已经被证实是由蒙古北部和中部的19个湖泊迁徙而来。三门峡湿地公园大天鹅越冬种群数量增加较快,是由于湖泊水质改善且人为大量投食玉米饲料,吸引了众多大天鹅前来越冬。蒙古环志的大天鹅连续多年在三门峡库区越冬也间接反映了这里有良好的栖息环境和丰富的食物资源。然而,初步推测,2015年这次大天鹅感染禽流感病毒可能与种群密度过高有较大的关系,建议当地政府合理投食补饲,不要盲目追求较多的种群数量;同时采取合理有效的措施促进大天鹅种群扩散,如在附近建立适宜的栖息地,这对于大天鹅种群保护具有重要意义。  相似文献   

12.
Identifying an organism's migratory strategies and routes has important implications for conservation. For most species of European ducks, information on the general course of migration, revealed by ringing recoveries, is available, whereas tracking data on migratory movements are limited to the largest species. In the present paper, we report the results of a tracking study on 29 Eurasian Teals, the smallest European duck, captured during the wintering period at three Italian sites. The departure date of spring migration was determined for 21 individuals, and for 15 the entire spring migratory route was reconstructed. Most ducks departed from wintering grounds between mid‐February and March following straight and direct routes along the Black Sea‐Mediterranean flyway. The breeding sites, usually reached by May, were spread from central to north‐Eastern Europe to east of the Urals. The migratory speed was slow (approximately 36 km/day on average) because most birds stopped for several weeks at stopover sites, mainly in south‐eastern Europe, especially at the very beginning of migration. The active flight migration segments were covered at much higher speeds, up to 872 km/day. Stopover duration tended to be shorter when birds were closer to their breeding site. These results, based on the largest satellite tracking effort for this species, revealed for the first time the main features of the migratory strategies of individual Teals wintering in Europe, such as the migration timing and speed and stopover localization and duration.  相似文献   

13.
Radar observations of the diurnal timing of bird migration in the Sahara Desert are presented for autumn migration. Study sites were on a transect along the north-south migratory direction. Three groups of birds migrating either during day, evening or night in the northern part of the Western desert in Egypt were identified. The maximum of day and night groups occurred later the further south the study sites were. Based on the distance between sites and the timing of peak migration, birds were flying at an estimated ground speed of about 20 m/s. The maximum of the evening group was at about 21:00 h at all sites. The three groups were classified according to three different strategies of migration across the Mediterranean Sea and the Sahara Desert: (1) the day group of birds performed a non-stop flight across the sea and at least the northern part of the desert; [2] the night group performed an intermittent migratory strategy with stopover at the coast of Egypt to continue migration the next evening; (3) the evening group birds were also intermittent migratory fliers, but they stopped somewhere in the desert after a continuous flight across the sea and part of the desert. About 20% of all migrants are involved in non-stop migration and 80% in intermittent migration with stopover at the coast (70%) or with stopover in the desert (10%). It is argued that any species of small passerine has the option to use any of the three strategies.  相似文献   

14.
环境温度变化通过影响鸟类的行为进而使其活动区也发生变化,探讨三者之间的关联性有助于理解鸟类是如何通过行为调整以适应周围环境的变化,来满足自身的生理需求。本研究通过卫星跟踪的方法获得了在河南三门峡湿地越冬的31只大天鹅(Cygnus cygnus)详细位点数据,在ArcGIS和R语言中采用核密度估计法计算大天鹅的活动区面积,在SPSS中采用Spearman分析平均温度与活动区面积的相关性;并利用瞬时扫描法获得大天鹅越冬行为观察数据,采用非参数Kruskal Wallis检验对大天鹅行为的差异性进行分析,探讨了环境温度与大天鹅越冬行为和活动区三者之间相互作用的模式。研究表明,从越冬初期至后期,随着环境温度的先下降后升高,大天鹅的取食、运动、静息等主要行为发生了较大的变化,静息和取食行为先增加后减少,运动行为则先减少后增加。越冬不同时期的核心区和活动区面积与温度呈显著性正相关。大天鹅在不同时段的活动区面积大小整体上均呈现出先减少后增加的趋势。随着环境温度的变化,大天鹅的越冬行为也随之发生了调整,进而使活动区面积发生改变,主要体现在越冬初期大天鹅通过增加活动区面积及时补充能量增加体能,越冬中期减少活动保持能量需求,越冬后期增加盘旋飞行使得活动区面积增大等。大天鹅这一系列行为和活动区的调整都是为了更好地满足越冬不同时期的生理需求。  相似文献   

15.
Juvenile songbirds on spring migration travel from tropical wintering sites to temperate breeding destinations thousands of kilometres away with no prior experience to guide them. We provide a first glimpse at the migration timing, routes, and stopover behaviour of juvenile wood thrushes (Hylocichla mustelina) on their inaugural spring migration by using miniaturized archival geolocators to track them from Central America to the U.S. and Canada. We found significant differences between the timing of juvenile migration and that of more experienced adults: juveniles not only departed later from tropical wintering sites relative to adults, they also became progressively later as they moved northward. The increasing delay was driven by more frequent short stops by juveniles along their migration route, particularly in the U.S. as they got closer to breeding sites. Surprisingly, juveniles were just as likely as adults to cross the Gulf of Mexico, an open-water crossing of 800–1000 km, and migration route at the Gulf was not significantly different for juveniles relative to adults. To determine if the later departure of juveniles was related to poor body condition in winter relative to adults, we examined percent lean body mass, fat scores, and pectoral muscle scores of juvenile versus adult birds at a wintering site in Belize. We found no age-related differences in body condition. Later migration timing of juveniles relative to adults could be an adaptive strategy (as opposed to condition-dependent) to avoid the high costs of fast migration and competition for breeding territories with experienced and larger adults. We did find significant differences in wing size between adults and juveniles, which could contribute to lower flight efficiency of juveniles and thus slower overall migration speed. We provide the first step toward understanding the “black box” of juvenile songbird migration by documenting their migration timing and en route performance.  相似文献   

16.
The tracking of small avian migrants has only recently become possible by the use of small light-level geolocators, allowing the reconstruction of whole migration routes, as well as timing and speed of migration and identification of wintering areas. Such information is crucial for evaluating theories about migration strategies and pinpointing critical areas for migrants of potential conservation value. Here we report data about migration in the common swift, a highly aerial and long-distance migrating species for which only limited information based on ringing recoveries about migration routes and wintering areas is available. Six individuals were successfully tracked throughout a complete migration cycle from Sweden to Africa and back. The autumn migration followed a similar route in all individuals, with an initial southward movement through Europe followed by a more southwest-bound course through Western Sahara to Sub-Saharan stopovers, before a south-eastward approach to the final wintering areas in the Congo basin. After approximately six months at wintering sites, which shifted in three of the individuals, spring migration commenced in late April towards a restricted stopover area in West Africa in all but one individual that migrated directly towards north from the wintering area. The first part of spring migration involved a crossing of the Gulf of Guinea in those individuals that visited West Africa. Spring migration was generally wind assisted within Africa, while through Europe variable or head winds were encountered. The average detour at about 50% could be explained by the existence of key feeding sites and wind patterns. The common swift adopts a mixed fly-and-forage strategy, facilitated by its favourable aerodynamic design allowing for efficient use of fuel. This strategy allowed swifts to reach average migration speeds well above 300 km/day in spring, which is higher than possible for similar sized passerines. This study demonstrates that new technology may drastically change our views about migration routes and strategies in small birds, as well as showing the unexpected use of very limited geographical areas during migration that may have important consequences for conservation strategies for migrants.  相似文献   

17.
Understanding the departure decisions of migratory birds is critical for determining how changing climatic conditions will influence subsequent arrival times on the breeding grounds. A long‐term dataset (1972–2008) of Whooper Swan Cygnus cygnus departure dates from a wintering site in Ireland was used to assess the factors determining the timing of migration. Early and late migrating swans showed different departure patterns. Earlier wintering ground departure was more pronounced for the first 50% of the population than the last 10% of departing individuals. Earlier departure was associated with an increase in February temperatures at the wintering site for all departure phases except the date when the last individual departed. The date by which the first 50% of Swans had departed was earlier with increasing numbers of wintering Swans, suggesting that competition on the wintering grounds may further influence the timing of departure. The results also suggested that departure is mediated by the influence of spring temperature on food resources, with increased February grass growth in warmer years enabling earlier departure of migrating Swans. To determine why arrival dates in the breeding ground have altered, environmental conditions in the wintering grounds must be taken into account.  相似文献   

18.
Lead poisoning of waterfowl through the ingestion of spent gunshot and discarded anglers' weights continues to be a problem worldwide. We took blood samples from 363 whooper swans Cygnus cygnus at wintering sites in Britain and Ireland and at moulting sites in Iceland during 2001–2005, and analysed them for total blood lead. Lead levels were generally low in swans in Iceland; 6% of samples exceeded 1.21  μ mol L−1, the level indicative of elevated lead and above background levels. The proportion of swans with elevated lead was much higher in the wintering range, varying between 43 and 70% at three sites monitored over the winters 2003/2004–2005/2006, and with blood lead levels ranging up to 19.6  μ mol L−1. The highest levels were in samples taken from swans in Scotland, with a mean value of 3.0  μ mol L−1, but nevertheless they indicated a marked decrease compared with blood lead levels measured for whooper swans at the same site 20 years ago. There also appeared to be a significant long-term decrease in the proportion of swans with elevated blood lead in Iceland, from 60% of birds in 1984 to 8% in 2005, although this may be due to the birds being caught in different parts of Iceland. The most likely source of elevated lead in whooper swans is spent gunshot. Management measures to reduce the impact of lead in the environment on the birds are discussed.  相似文献   

19.
Determining patterns in annual movements of animals is an important component of population ecology, particularly for migratory birds where migration timing and routes, and wintering habitats have key bearing on population dynamics. From 2009 to 2011, we used light‐level geolocators to document the migratory movements of Flammulated Owls (Psiloscops flammeolus). Four males departed from breeding areas in Colorado for fall migration between ≤5 and 21 October, arrived in wintering areas in Mexico between 11 October and 3 November, departed from wintering areas from ≤6 to 21 April, and returned to Colorado between 15 and 21 May. Core wintering areas for three males were located in the Trans‐Mexican Volcanic Belt Mountains in the states of Jalisco, Michoacán, and Puebla in central and east‐central Mexico, and the core area for the other male was in the Sierra Madre Oriental Mountains in Tamaulipas. The mean distance from breeding to wintering centroids was 2057 ± 128 km (SE). During fall migration, two males took a southeastern path to eastern Mexico, and two males took a path due south to central Mexico. In contrast, during spring migration, all four males traveled north from Mexico along the Sierra Madre Oriental Mountains to the Rio Grande Valley and north through New Mexico. The first stopovers in fall and last stopovers in spring were the longest in duration for all males and located 300–400 km from breeding areas. Final spring stopovers may have allowed male Flammulated Owls to fine tune the timing of their return to high‐elevation breeding areas where late snows are not uncommon. One male tracked in both years had similar migration routes, timing, and wintering areas each year. Core wintering and final stopover areas were located primarily in coniferous forests and woodlands, particularly pine‐oak forests, suggesting that these are important habitats for Flammulated Owls throughout their annual cycle.  相似文献   

20.
According to migration theory and several empirical studies, long‐distance migrants are more time‐limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is often also influenced by environmental factors such as food availability and wind conditions. Using GPS tags, we tracked 65 greater white‐fronted geese Anser albifrons migrating between western Europe and the Russian Arctic during spring and autumn migration over six different years. Contrary to theory, our birds took considerably longer for spring migration (83 days) than autumn migration (42 days). This difference in duration was mainly determined by time spent at stopovers. Timing and space use during migration suggest that the birds were using different strategies in the two seasons: In spring they spread out in a wide front to acquire extra energy stores in many successive stopover sites (to fuel capital breeding), which is in accordance with previous results that white‐fronted geese follow the green wave of spring growth. In autumn they filled up their stores close to the breeding grounds and waited for supportive wind conditions to quickly move to their wintering grounds. Selection for supportive winds was stronger in autumn, when general wind conditions were less favourable than in spring, leading to similar flight speeds in the two seasons. In combination with less stopover time in autumn this led to faster autumn than spring migration. White‐fronted geese thus differ from theory that spring migration is faster than autumn migration. We expect our findings of different decision rules between the two migratory seasons to apply more generally, in particular in large birds in which capital breeding is common, and in birds that meet other environmental conditions along their migration route in autumn than in spring.  相似文献   

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