Chromosomal analysis in Cathartidae: distribution of heterochromatic blocks and rDNA, and phylogenetic considerations

Three species of Cathartidae (Sarcoramphus papa, Cathartes aura and Cathartes burrovianus) were cytogenetically characterized by G- and C-banding. 18S–28S rDNA was used as a probe to map major ribosomal clusters. These species showed very similar karyotypes, with 2n = 80, 10 pairs of macrochromosomes, a submetacentric Z and a metacentric W chromosome. However, differences were found in the amount and distribution of heterochromatic blocks: S. papa showed heterochromatin only in the pericentromeric region and in chromosome W, while both species of Cathartes had heterochromatic blocks also in the long arm of two acrocentric pairs. Ribosomal clusters were found in a small pair in all three species. Karyotype analysis in Cathartidae revealed that this family has retained similarities to the putative avian ancestral karyotype, and placed Cathartidae in a more basal position in relation to Accipitridae and Falconidae. However, the cytogenetic data still cannot clarify the phylogenetic relationship between this family and other groups, such as Ciconiidae, considered its sister-group according to nucleic acid hybridization studies. J. C. Pieczarka and C. Y. Nagamachi—Researcher from CNPq, Brazil.     

秃鹫巢内育雏期亲鸟与幼鸟行为及时间分配

2016和2017年,采用焦点动物取样法及全事件记录法,在新疆和静县巴仑台镇研究了4个繁殖巢的秃鹫(Aegypius monachus)繁殖行为。通过红外相机和人工观察,构建了秃鹫巢内育雏期的行为谱,将秃鹫亲鸟的行为划分为9类33种,将雏鸟行为划分为6类28种。结果表明,亲鸟喂食次数的最高峰出现在12:30~13:30时,随后在15:30~18:30时之间出现一个小高峰。在育雏期,亲鸟行为以护幼、观望和警戒为主,雏鸟则以休息和观望为主。将巢内育雏期分为三个阶段:育雏前期(4~5月)、育雏中期(6月)、育雏后期(7月),运用单因素方差分析(one-way ANOVA)检验不同育雏阶段亲鸟、雏鸟行为时间分配的差异。结果显示,育雏前期与后期之间亲鸟的行为时间分配差异不显著(P0.05),前期与中期和中期与后期之间,亲鸟的行为时间分配差异均显著(P0.01);育雏前期、中期与后期的雏鸟行为时间分配差异均显著(P0.01)。国内秃鹫繁殖主要面临食物短缺、人类活动干扰等威胁。     

卫星跟踪中蒙之间秃鹫春季迁徙路线及活动区域

秃鹫(Aegypius monachus)被世界自然保护联盟(IUCN)列为近危物种。每年冬季或者早春在渤海湾都会救护到因体质较弱而无法飞行的秃鹫,为了对秃鹫及其迁徙路线进行更有效的保护,于2016年春季对两只救护放飞秃鹫(ID1051和ID2016),利用卫星跟踪技术研究其迁徙路线和活动区,旨在为秃鹫的救护和保护提供基础资料。结果表明,ID1051和ID2016都迁徙到蒙古国的布尔干省和后杭爱省交界处,行程分别为2 200 km和2 400 km。ID2016在度夏初期、中期和后期的活动区面积(50%Fixed Kernel),分别为31 261.01km^2、1 492.96 km2和11 027.70 km^2。秃鹫在迁徙过程中主要时间在静息,其次是飞行和寻觅行为。在0至7时和19至24时,即晨昏和夜间秃鹫都处于静止状态。从8时开始,秃鹫开始活动,并在12和13时达到活动高峰,随后活动逐渐趋缓,直至18时趋于静止状态。本文提供了秃鹫的春季迁徙路线以及重要中途停歇地,为秃鹫的救护和保护提供了基础资料。     

Rewilding traditional grazing areas affects scavenger assemblages and carcass consumption patterns

The abandonment of traditional livestock farming systems in Mediterranean countries is triggering a large-scale habitat transformation, which, in general, consists of the replacement of open grazing areas by woodlands through non-managed regeneration. As a consequence, wild ungulates are occupying rapidly the empty niche left by domestic ungulates. Both types of ungulates represent the main trophic resource for large vertebrate scavengers. However, a comparison of how vertebrate scavengers consume ungulate carcasses in different habitats with different ungulate species composition is lacking. This knowledge is essential to forecast the possible consequences of the current farmland abandonment on scavenger species. Here, we compared the scavenging patterns of 24 wild and 24 domestic ungulate carcasses in a mountainous region of southern Spain monitored through camera trapping. Our results show that carcasses of domestic ungulates, which concentrate in large numbers in open pasturelands, were detected and consumed earlier than those of wild ungulate carcasses, which frequently occur in much lower densities at more heterogenous habitats such as shrublands and forest. Richness and abundance of scavengers were also higher at domestic ungulate carcasses in open habitats. Vultures, mainly griffons (Gyps fulvus), consumed most of the carcasses, although mammalian facultative scavengers, mainly wild boar (Sus scrofa) and red fox (Vulpes vulpes), also contributed importantly to the consumption of wild ungulate carcasses in areas with higher vegetation cover. Our findings evidence that the abandonment of traditional grazing may entail consequences for the scavenger community, which should be considered by ecologists and wildlife managers.     

大山雀身体大小的性二态及其季节变化

动物中普遍存在雌雄个体身体大小的性二态现象。了解近缘种之间身体大小性二态现象的差异，可为深入探讨身体大小性二态现象的潜在驱动机制提供证据。国外对欧亚大山雀（Parus major）的研究发现，其喙长、跗跖长、翅长等 6 项身体大小指标存在着明显的性二态，且喙长的性二态存在季节间差异。大山雀（P. cinereus）曾被作为欧亚大山雀的一个亚种，其形态和行为与欧亚大山雀存在着诸多相似之处。为探讨大山雀是否也存在身体大小性二态及季节性差异，本研究分析了 2018 至 2020 年间在河南董寨国家级自然保护区捕捉的 226 只（雌性 96 只和雄性 130 只）大山雀的喙长、头喙长、跗跖长、翅长、尾长和体长这 6 项体征指标的两性差异及其季节变化。结果显示，大山雀上述 6 项身体大小指标均存在不同程度的性二态现象，且雄性个体仅喙长与雌性的差异不显著，其余 5 项指标均显著大于雌性。此外，身体大小指标的两性差异不随季节显著变化，但两性的跗跖长在秋季均显著短于冬季和繁殖季，尾长在繁殖季均显著长于秋季和冬季。上述结果表明，大山雀身体大小的性二态及其季节性差异与欧亚大山雀并不完全相似。无论其身体大小存在性二态和季节变化的原因，还是其与欧亚大山雀在身体大小性二态模式上的差别，都有待今后进一步的研究。     

秃鹫骨骼的解剖学特点

对秃鹫(aegypius monachus)骨骼进行了详细的观察、描述和功能分析.结果表明,其头骨较宽;上喙粗长、前端近垂直下弯;前额骨游离,眶突发达;龙骨突不发达;叉骨呈"U"形,叉骨头膨大、具发达的叉骨,乌喙骨关节面;前肢骨明显长于后肢骨;第一掌骨伸肌突发达;跗跖骨前后宽扁,跗后跟嵴短;足部近端趾节略长于远端趾节.这些特征与秃鹫的取食方法与偏好及飞行与栖息特点密切相关.     

Obligate vertebrate scavengers must be large soaring fliers

Among extant vertebrates, only the 23 species of vulture are obligate scavengers. We use an energetic modelling approach to explore the constraints imposed by an obligate scavenging lifestyle, and to ask whether obligate scavengers must always be avian and generally large-bodied users of soaring flight. Our model found that aerial scavengers always out-competed postulated terrestrial ones, mainly because flight allows area to be searched much more rapidly for carrion. Soaring was favoured over flapping flight because the reduction in flight speed (and so rate of area search) was more than compensated for by the decrease in the costs of transport. Large individual size is selected for if carrion is available in large packages, when obligate scavenger feed only infrequently, and so must be able to survive on body reserves in the periods between discovering food falls. In the absence of avian radiation, an obligate terrestrial scavenger seems energetically feasible, but we argue that such a beast is unlikely to have evolved. In birds, in order to become exclusive scavengers, vultures have needed to specialize for efficient soaring flight as a low energy form of travel, and as a consequence they have lost the agility needed to kill prey. In mammals, however, no comparable trade-off occurs. So for terrestrial carnivores there is probably no strong selection pressure towards being an exclusive scavenger. Indeed it will perhaps always be more advantageous to retain the flexibility of obtaining food by either predation or scavenging.     

Nesting distribution of vultures in relation to land use in Swaziland

Three species of vulture (African White-backed, White-headed and Lappet-faced) breed in Swaziland, all of which are threatened within the country. Vulture nests were surveyed using a fix-winged aircraft in low-lying savannas of Swaziland. Nesting was observed in three land use categories: (1) unprotected government cattle ranches, (2) protected cattle ranches, and (3) conservation areas. A total of 248 nests was recorded, of which 240 belonged to the African White-backed Vulture. Nesting densities were highest in conservation areas, an order of magnitude lower on protected cattle ranches and negligible on government ranches. Nests of White-headed Vultures and Lappet-faced Vultures were exclusively located in conservation areas. Nesting densities of African White-backed Vultures in some conservation areas exceeded 260 nests/100 km², which are the highest known densities of this species anywhere in Africa. Nests were almost exclusively located in riparian vegetation, but at Hlane National Park a large proportion of nests were placed in open woodland, possibly as a result of an influx of vultures from adjoining agricultural lands that have only been transformed in recent decades. Where elephants were present in conservation areas, vultures did not nest within their enclosures. The location and density of vulture nests may possibly be used as an indicator of pressure on biological resources in low-lying savannas of Swaziland.     

Comparison of lead contamination among related scavenging birds sharing food sources: a call for caution when using surrogate species

Lead contamination is a global problem affecting a large number of bird species around the world. Among the different avian guilds, vultures and facultative scavengers are particularly threatened by this toxic metal. However, little information is available about differences in exposure to this metal for sympatric vulture species that share food resources. We compared blood lead concentrations of two closely related sympatric obligate scavenger species, the abundant Black Vulture Coragyps atratus and the threatened Andean Condor Vultur gryphus in north-western Patagonia, Argentina. We sampled 28 Andean Condors and 29 Black Vultures trapped foraging in the same area in the steppe. We also sampled 16 Black Vultures foraging in a rubbish dump to determine whether there were differences in lead contamination among foraging sites. Andean Condors had significantly higher mean blood lead concentrations than Black Vultures. There was no difference in lead concentrations between Black Vultures trapped in the steppe and in the rubbish dump. The prevalence and probability of lead concentrations above the threshold level (20 µg/dL) was higher for Andean Condors than for Black Vultures, potentially producing different effects on their health. This disparity in lead contamination may be due to differences in their foraging habits or in their susceptibility to this toxic metal. Overall, our results suggest caution in using an abundant surrogate species to infer lead contamination in a closely related but harder to sample species.     

Population size and breeding success of the Cinereous Vulture,Aegypius monachus,in a newly found breeding area in western Anatolia (Aves: Falconiformes)

A total of 123 nests of the Cinereous Vulture, Aegypius monachus, was found in three different nesting areas in Middle Sakarya Region, Western Turkey, during three years. The number of breeding pairs was 32 in 2010, 46 in 2011 and 42 in 2012. This is the largest Cinereous Vulture colony in Turkey and the most important breeding area in the western part of its distribution outside Spain. Breeding success was 0.78 fledgling per occupied nest in 2010, 0.73 in 2011 and 0.54 in 2012. The most unsuccessful breeding occurred mostly between May and July, when recreational activities and various economic human activities increased in the area.