江西省中华秋沙鸭越冬种群现状调查与胁迫因素分析

于2009年2月对江西省五大水系:赣江、抚河、信江、饶河和修水的越冬中华秋沙鸭种群展开专项调查,分析了江西省越冬中华秋沙鸭种群的数量、性比、空间分布格局、生境特征及其胁迫因素.主要采用样线法在五大水系的主要河道展开同步调查,调查样线总长度400 km.结果发现,江西省越冬中华秋沙鸭有26个生活群255只个体,雌雄性比为119:117,其生活群雌雄性比也多接近1:1.江西省五大水系中,除赣江外,在其他4个水系均发现有中华秋沙鸭越冬群体.除了在曾有中华秋沙鸭越冬记录的婺源、贵溪、弋阳、浮梁、修水发现其越冬群体外,还首次在江西省境内的宜黄、武宁和龙虎山地区发现有较大的中华秋沙鸭越冬群体,而且龙虎山泸溪河段分布有本次调查中个体数量最大的有53只个体的群体.人类采砂活动、水质污染、非法捕鱼和家禽饲养是目前影响该种群生存的主要胁迫因素.     

江西鄱阳湖流域中华秋沙鸭越冬期间的集群特征

2010年11月—2011年3月,采用样线法对江西鄱阳湖流域8个河段的中华秋沙鸭Mergus squamatus的集群特征进行了研究。中华秋沙鸭的集群类型包括雄性群、雌性群、混合群、雌性孤鸭和雄性孤鸭5种类型。越冬期间共记录到89群次,432只次中华秋沙鸭。其中,混合群是最多的一种集群方式,孤鸭也是越冬期间出现频次较高的一种特殊的集群方式。集群类型存在时间变化(P<0.01)。混合群中,大多数群体中雌性个体数多于雄性个体或者是一雌一雄。89群次中,孤鸭和2—8只群占总群数的87.64%,提示中华秋沙鸭主要以集小群分散活动。中华秋沙鸭越冬期间的群体大小是(4.85±4.97)只/群。不同集群类型的群体大小差异较大。集群大小可能与采砂、捕鱼、食物的丰富度等环境因子有关。调查结果显示,中华秋沙鸭越冬期间的性比是1∶0.74(n=432)。中华秋沙鸭群体大小与性比有一定的关系。     

广东惠东白盆珠水库中华秋沙鸭越冬群体监测

中华秋沙鸭(Mergus squamatus)是典型的森林溪流生态系统的指示种,鲜有在人工水体大群越冬的报道。2007年9月至2013年3月,连续6年在广东白盆珠水库发现其越冬群体。监测结果如下:1)中华秋沙鸭最早可于9月底到达白盆珠水库,在翌年3月陆续迁离,居留时间最短为3个月左右,最长为6个月左右;2)2007～2009年,其最大群体数量基本保持稳定,均为31只;2009～2013年,数量逐年减少,最少时为12只;3)其活动区域较稳定,皆在白盆珠水库的打锣岽附近,活动范围100.01～180.90 hm2,该位置水体宽阔,水质洁净,受外界干扰少。我们认为,水库拥有较理想的自然栖息环境和保护区有效管理是中华秋沙鸭在此越冬的关键因素;为了进一步加强对中华秋沙鸭的保护力度,建议将白盆珠水库打锣岽附近区域划为广东省惠东莲花山白盆珠省级自然保护区核心区。     

江西宜黄、武宁发现中华秋沙鸭越冬群体

中华秋沙鸭(Mergus squamatus)属雁形目(Anseriformes)鸭科(Anatidae),分布地狭窄,繁殖地主要在俄罗斯东南部、北朝鲜和中国东北地区,越冬地主要在中国的中部和南部地区,少量越冬个体曾见于日本、南朝鲜和台湾,以及缅甸、泰国和越南北部地区(郑作新,1987;何芬奇等,2006).目前全球仅存约1 000～2 499只中华秋沙鸭成体,濒临灭绝(BirdLife International,2008),被世界自然保护联盟(IUCN)红皮书列为濒危种;我国也将中华秋沙鸭列为国家I级重点保护野生动物.     

湖南沅陵发现中华秋沙鸭越冬种群

正2010年8月和2011年6月,我们在黑龙江带岭分别为2只中华秋沙鸭(Mergus squamatus)佩戴了卫星发射器(12 g,美国Northstar公司生产)。根据卫星跟踪提供的信息,我们于2014年1月在湖南沅陵县境内的沅江支流南滩河(28°50.869'N,110°48.521'E)和鸟儿巢水电站库区(28°50.332'N,110°51.728'E)分别发现3只(1♂、2♀)和1只(♂)越冬中华秋沙鸭个体。同期在沅江五强溪水电站大坝下游(28°46.478'N,110°56.242'E)发现中华秋沙     

天目溪中华秋沙鸭生态习性研究

中华秋沙鸭Mergus squamatus是全球濒危物种。2015—2018年在浙江省杭州市临安区天目溪开展了该物种越冬种群的监测研究。调查累计发现25群中华秋沙鸭,计106只次,平均每群4. 24只±0. 98只,性比为1∶3. 82,主要集成3～6只/群,分为3个类群,即孤雌群、雌性群和混和群。中华秋沙鸭主要栖息于开阔的河道,河宽30～60 m,附近有沙洲;水体较浅,水深40～60 cm;水流平缓,水流速度为0. 3～0. 5 m·s~(-1)。中华秋沙鸭对人为活动十分敏感,其栖息地远离居民点,距公路的距离可至30 m以内,但这种生境需要茂密的乔灌木或竹林隔离。     

普通秋沙鸭

正中国有4种秋沙鸭,即白秋沙鸭(斑头秋沙鸭)、中华秋沙鸭、红胸秋沙鸭和普通秋沙鸭,其中普通秋沙鸭是秋沙鸭中个体最大、数量最多、分布最广的一种。普通秋沙鸭体长54~68厘米,成年个体体重可达1~2千克。别看普通秋沙鸭名字无奇,可是给它起名的人,却大有来头。1758年瑞典博物学家林奈第一次描述了普通秋沙鸭。普通秋沙鸭繁殖于北美洲北部和欧亚大陆,南下到美国南部和中国中部过冬。冬季和迁徙期间在中国东部和长江流域是常见的,而且种群数量较大,遍布于各种湖泊、山区溪流和低地。     

群体规模对越冬灰鹤警戒行为的影响

2005年1—3月,在云南丽江拉市海就群体规模对越冬灰鹤(Grusgrus)警戒行为的影响进行了研究。用扫描取样记录群体的规模和警戒个体的数量、用焦点取样记录群体中个体警戒行为的频次和持续时间,结果显示灰鹤群体和个体的警戒力均随群体规模增加而降低,但集群个体数超过30只后,群体警戒力便不会再下降(P>0.05)、成体的警戒持续时间也会增加(P<0.01);当群体规模超过50只后,成体的警戒频次也会上升(P<0.05)。推测亚成体维持低警戒的群体规模上限值要高于成体,单从警戒行为分析,20—30只个体的集群可能代表越冬灰鹤的最适群体大小。     

近十年来鄱阳湖区越冬白鹤种群数量与分布

1998—2010年,该研究采用地面同步调查法在鄱阳湖区64个湖泊开展了越冬白鹤种群监测。结果表明,鄱阳湖区分布有稳定的越冬白鹤种群,鄱阳湖区越冬白鹤种群数量年平均值为(3108±849)只,2002年冬季达到最大值4004只;从2003年开始鄱阳湖区越冬白鹤数量表现出一定的年际波动,但变化幅度较小。共有46个湖泊被记录到有白鹤活动。其中,达到全球白鹤种群数量1%标准以上的湖泊达25个;白鹤数量接近或超过全球白鹤种群数量的40%,即1280只个体以上的湖泊包括鄱阳湖国家级自然保护区内的大汊池、蚌湖和蚕豆湖,以及保护区外的南湖。自然保护区涵盖了越冬白鹤的主要聚集湖泊。分布在自然保护区内的白鹤占鄱阳湖区越冬白鹤种群总数量的(66±27.3)%。保护区外分布的白鹤数量虽然总体呈下降趋势,但仍分布有一定数量的个体。     

四川鸟类一新记录--白鹈鹕

2003年9月27日早晨6:00左右,村民在四川省南充市西北郊外舞凤山下发现16只白鹈鹕(Pelecanus onocrotalus),经驱赶到南充市北干道一建筑物周围(彩版见封面),由于围观人群影响,于10∶02飞离.该鸟在四川是首次记录,国内近年亦未有野外记录报道.据1990年和1992年国际水禽研究局组织的亚洲隆冬水鸟调查,我国未见到;据1992年调查,在整个亚洲的越冬种群数量为5666只,其中西亚547只,南亚5119只[1];20世纪60年代在我国青海湖与大天鹅混群越冬,每年约4～6只,70年代以后青海湖未再见有越冬个体,国内无驯养繁殖记录[2].本次四川首次发现该鸟,对研究其迁徙通道和国内分布及保护有一定的意义.     

Using Species Distribution Model to Estimate the Wintering Population Size of the Endangered Scaly-Sided Merganser in China

Scaly-sided Merganser is a globally endangered species restricted to eastern Asia. Estimating its population is difficult and considerable gap exists between populations at its breeding grounds and wintering sites. In this study, we built a species distribution model (SDM) using Maxent with presence-only data to predict the potential wintering habitat for Scaly-sided Merganser in China. Area under the receiver operating characteristic curve (AUC) method suggests high predictive power of the model (training and testing AUC were 0.97 and 0.96 respectively). The most significant environmental variables included annual mean temperature, mean temperature of coldest quarter, minimum temperature of coldest month and precipitation of driest quarter. Suitable conditions for Scaly-sided Merganser are predicted in the middle and lower reaches of the Yangtze River, especially in Jiangxi, Hunan and Hubei Provinces. The predicted suitable habitat embraces 6,984 km of river. Based on survey results from three consecutive winters (2010–2012) and previous studies, we estimated that the entire wintering population of Scaly-sided Merganser in China to be 3,561 ± 478 individuals, which is consistent with estimate in its breeding ground.     

Gravel Bars Can Be Critical for Biodiversity Conservation: A Case Study on Scaly-Sided Merganser in South China

Gravel bars are characteristic components of river landscapes and are increasingly recognized as key sites for many waterbirds, though detailed studies on the ecological function of gravel bars for waterbirds are rare. In this study, we surveyed the endangered Scaly-sided Merganser Mergus squamatus along a 40 km river section of Yuan River, in Central China, for three consecutive winters. We derived the landscape metrics of river gravel bars from geo-rectified fine resolution (0.6 m) aerial image data. We then built habitat suitability models (Generalized Linear Models—GLMs) to study the effects of landscape metrics and human disturbance on Scaly-sided Merganser presence probability. We found that 1) the Scaly-sided Merganser tended to congregate at river segments with more gravel patches; 2) the Scaly-sided Merganser preferred areas with larger and more contiguous gravel patches; and 3) the number of houses along the river bank (a proxy for anthropogenic disturbance) had significantly negative impacts on the occurrence of the Scaly-sided Merganser. Our results suggest that gravel bars are vital to the Scaly-sided Merganser as shelters from disturbance, as well as sites for feeding and roosting. Therefore, maintaining the exposure of gravel bars in regulated rivers during the low water period in winter might be the key for the conservation of the endangered species. These findings have important implications for understanding behavioral evolution and distribution of the species and for delineating between habitats of different quality for conservation and management.     

长白山中华秋沙鸭的种内巢寄生

雁形目鸟类的种内巢寄生现象十分普遍,但有关中华秋沙鸭(Mergussquamatus)的种内巢寄生现象未见报道。2019年4和5月,从长白山1个中华秋沙鸭人工巢的视频监控发现,1只雌鸭在亲鸟孵卵时强行进入巢箱趴卧约29 min。其后根据该巢窝卵数的增加、超常窝卵数和窝卵不同步孵化3个指标,确认该巢存在种内巢寄生现象。宿主对进入巢内寄生的个体表现出强烈的攻击行为,但对寄生卵未表现出明显的拒卵行为。由于区域内仍有较多巢箱未被利用,中华秋沙鸭的种内巢寄生行为是否源于对有限巢址资源的竞争,有待进一步研究。     

The relationship between dominance behaviour, bill size and age group in Greater Sheathbills Chionis alba

A dominance hierarchy developed within a wintering flock of Greater Sheathbills which fed regularly at a concentrated artificial food source. Each bir's dominance position was determined from the proportion of interactions in which it was displaced, and from the number of other birds which it was seen to displace.
Most dominant birds were known to be over 6 or 7 years of age. They had larger bills than their subordinates had and initiated displacement interactions more often. After each interaction the displacer resumed feeding more quickly than the bird it displaced. Although dominant birds had a higher average peck rate, they did not maintain a higher body mass throughout the winter, nor did they show a higher survival rate than their subordinates.     

婺源鸟类纪录解析

迄今为止在婺源先后共记录到鸟类302种,分属63科,其中非雀形目鸟类32科143种、雀形目鸟类31科159种。同时,婺源保存有某些特殊鸟种的独立群体,如靛冠噪鹛(Garrulax coutoisi),2011~2013年繁殖季节的统计结果其总数量超过250只;白腿小隼(Microhierax melanoleucos)在婺源有近50处的繁殖点,分布遍及婺源全境,其有效种群数量至少在40个繁殖对以上,总数量在120只个体上下;小太平鸟(Bombycilla japonica)在婺源有一个小的居留群,繁殖季节分成2个小群,2013年1月27日曾见到70余只;作为留鸟的鸳鸯(Aix galericulata),在婺源有繁殖点近百个,数量达上千只。婺源还记录有濒危鸟种栗夜(Gorsachius goisagi)和虎斑夜(G.magnificus)。     

Eimeria acervulina: The influence of inoculation dose on transmission between broiler chickens

The course and clinical appearance of an Eimeria species infection in chicken flocks depend on the response of an individual bird to infection and on population-dynamics of the infection in the flock. Differences in ingested numbers of oocysts may affect oocyst load in the flock and the subsequent infectious dose for not yet infected birds. To study the link between numbers of oocysts excreted by infected birds and transmission of Eimeria acervulina, experiments were carried out with 42 pairs of broiler chickens using inoculation doses with 5, 50, 500 or 50,000 sporulated oocysts. In each pair one bird was inoculated and the other bird was contact-exposed. All contact birds became infected, which occurred on average within 34 h after exposure to an inoculated bird. Although a higher inoculation dose resulted in higher oocyst excretion in inoculated and contact-infected birds, only small non-significant differences in transmission rates between groups were found.     

棕臀噪鹛——中国鸟类物种新记录

2007年5月,在云南南部思茅地区(今普洱市)江城县西南部的整董镇附近发现棕臀噪鹛(Garru-laxgularis),调查表明该种在江城南部沿中国—老挝边界一带分布;此发现为该种在中国的首次正式纪录,期待今后在西藏东南部地区对该种有新的发现。