Vulture Research Update: October-November

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In this research update we summarise articles on the status of the world’s raptor and vulture species; a global review of vulture and condor tracking studies; and two articles that use GPS tracking data to study the movement patterns of bearded and Egyptian vultures.

State of the world’s raptors: Distributions, threats, and conservation recommendations. McClure et al. 2018. Biological Conservation

The authors of this study reviewed the International Union for the Conservation of Nature’s (IUCN) Red List to examine the conservation status, distributions, threats and conservation recommendations for all 557 raptor species.

They also assess the significance of Important Bird and biodiversity Areas (IBAs) for raptor and vulture species, as well as which countries contain the most species listed under the Memorandum of Understanding of the Conservation of Migratory Birds of Prey in Africa and Eurasia (Raptors MoU).

The study confirms that raptors and especially Old World vultures are more threatened than birds in general. Eighteen percent of raptor species are threatened with extinction and more than half (52%) have declining global populations.

Indonesia has the highest number of raptor species (119) and the most declining species (63). Russia and China contain the highest number of Raptors MoU species, but neither have signed up to the agreement. Six of the ten most important IBAs for raptors are in Nepal.

Raptor species that require forest are the most threatened, with agriculture and logging as the most frequent threats, while poisoning is confirmed as the most serious threat for Old World vultures.

The highest priority conservation actions include preventing mortality, conserving key habitats and sites and improving long-term monitoring, particularly in the case of Old World vultures.

A three-decade review of telemetry studies on vultures and condors. Alarcón & Lambertucci. 2018. Movement Ecology

The authors of this study provide the first comprehensive global review of telemetry (tracking) studies on vultures and condors from the last thirty years.

The 97 articles that were reviewed were mainly published in the last decade and focused on the movements of individuals from 14 species (61% of the extant species) in 24 countries.

The studies have provided important information about the ecology of the different species which can inform conservation strategies. The most studied aspects of vulture and condor movement ecology were foraging movements and home range studies, whereas commuting and dispersal movements were only investigated by a few studies.

24 studies considered conservation and management of threatened species which illustrates the value of tracking data for informing conservation strategies, as shown in another recent study.

Several information gaps were identified which should help to focus research efforts and funding priorities. These included extending studies to under-studied vulture species; investigating the dispersal phase more thoroughly; and improving our understanding of how internal variables (e.g. navigation skills) shape movement decisions of individual vultures (see next month’s review for an interesting new study on this subject).

Finally, the authors promote collaborative approaches to use existing and future datasets to improve our understanding of vulture ecology in order to effectively inform conservation strategies.

Drivers of daily movement patterns affecting an endangered vulture flight activity. Garcia-Jiménez et al. 2018. BMC Ecology

This study used GPS tracking data to assess the relative influence of external factors (season and daylight time) and internal factors (sex, breeding season and territorial status) on the movement patterns of 19 bearded vultures in the Pyrenees between 2006 and 2016.

The results showed that non-territorial bearded vultures (“floaters”) spent longer periods in flight and travelled further each day, which was expected because their movements were not restricted to a certain distance from a nest site or territory.

Overall, individuals travelled further during the breeding season, with females travelling further in total and a greater distance from the nest site than males both during and outside the breeding season. Flight activity increased during the last three quarters of daylight and was greatest in Spring, which coincides with the peak of the breeding period when chicks are hatching.

This study provides a first detailed assessment of the daily flight patterns of bearded vultures which improves our understanding of their movement ecology and provides useful information for the conservation and management of the species.

Food predictability and social status drive individual resource specializations in a territorial vulture. Van Overveld et al. 2018

The authors of this study used high resolution GPS tracking data to study the movements of 45 Egyptian vultures tracked for one year on the island of Fuerteventura in the Canaries, with a focus on how individual characteristics and spatial constraints shaped their use of human-provided carrion.

The results showed that the Egyptian vultures used predictable food sources (feeding sites, waste dumps) regularly, especially during the non-breeding season (July-December) while flight activity increased during the breeding season (January-June).

Females were socially dominant over males and territorial birds were socially dominant over non-territorial birds, with social status also increasing with age.

Competitive superior individuals (females) used the feeding station consistently throughout the year while subdominant individuals (especially males) favoured farms as their main source of food, although these patterns varied depending on season and territorial status.

These results demonstrate for the first time the asymmetric use of supplementary feeding sites, a widely used tool for conserving Egyptian vultures, and suggest that feeding stations could drive differential use of resources within populations.

This study confirms that predictable food sources play an important role in driving the movement patterns of Egyptian vultures and will inform future analyses and interpretation of the GPS tracking data collected during the LIFE Rupis project.

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