Identifying critical migratory bottlenecks and high‐use areas for an endangered migratory soaring bird across three continents

Abstract

Migrant birds face a number of threats throughout their annual cycle, including persecution, collision with energy infrastructure, and habitat and climate change. A key challenge for the conservation of migrants is the identification of important habitat, including migratory concentration areas, because species survival rates may be determined by events in geographically very limited areas. Remote‐tracking technology is facilitating the identification of such critical habitat, although the strategic identification of important sites and incorporation of such knowledge in conservation planning remains limited. We tracked 45 individuals of an endangered, soaring migrant (Egyptian vulture Neophron percnopterus), over 75 complete migrations that traversed three continents along the Red Sea Flyway. We summarize and contextualize migration statistics by season and age class, including migration start, midpoint, and end dates, as well as linear and cumulative migration distance, migration duration and speed, and route straightness. Then, using dynamic Brownian bridge movement models, we quantified space use to identify the most important migratory bottlenecks and high‐use areas on the flyway. These areas each accounted for < 5% of the overall movement range of the tracked birds, yet > 20% of all tracks passed through bottlenecks, and > 50% of the overall vulture time spent on migration fell within high‐use areas. The most important sites were located at the southeastern Red Sea coast and Bab‐el‐Mandeb Strait (Saudi Arabia, Yemen, Djibouti), the Suez Canal zone (Egypt), and the Gulf of Iskenderun (Turkey). Discouragingly however, none of the area within the major migratory bottlenecks was protected and < 13% of the high‐use areas were protected. This demonstrates a very concerning gap in the protected area network for migratory soaring birds along the Red Sea Flyway. Because reducing threats at migratory concentrations can be a very efficient approach to protect populations, our work provides clear guidelines where conservation investment is urgently needed to benefit as many as 35 migratory soaring‐bird species that regularly use the Red Sea Flyway.

Comparing abundance distributions and range maps in spatial conservation planning for migratory species

“…Populations are especially vulnerable if large numbers of individuals aggregate in unprotected sites (Buechley et al. ). Consequently, conservation should consider the relative abundance of species, because the value of any given site for conservation will usually increase as the number of individuals increase (Johnston et al.…”

“…However, even seasonal range maps fail to capture spatial or temporal variation in abundance, which is particularly problematic for migratory species or species that have highly variable abundance across their range (Dallas et al 2017). Populations are especially vulnerable if large numbers of individuals aggregate in unprotected sites (Buechley et al 2018). Consequently, conservation should consider the relative abundance of species, because the value of any given site for conservation will usually increase as the number of individuals increase , Veloz et al 2015.…”

Monitoring Results from the Breeding Group of Egyptian Vulture at Narat-Tyube Ridge and GPS/GSM Tracking Data from Juvenile Egyptian Vultures (Republic of Dagestan, Russia)

“…Для балканских и закавказских популяций стервятников пути миграции и места зимовки изучены уже достаточно хорошо. Так болгарские птицы в основном мигрируют через Турцию, Сирию, Ливан, Израиль и Египет в Африку, проходя на своём пути сразу же три «бутылочных горлышка», тем не менее, некоторая часть птиц летит вдоль северного побережья Красного моря в Йемен и Джибути (Buechley et al, 2013;Buechley et al, 2018b;Bougain, Oppel, 2016) (Buechley et al, 2018a), см. рис.…”

“…Juvenile Egyptian Vultures, tagged with trackers in the Balkans, started migration from 2 to 19 September and successfully reach wintering areas on September 24 -November 11 (Bougain, Oppel, 2016;. Migration of Dagestan Egyptian Vultures showed similarity to migration of Balkan and Armenian birds, and routes are identical to birds from Armenia (see figure 3 and table 4, Buechley et al, 2018b).…”

“…Northern populations of Egyptian Vultures undertake long migrations (García-Ripollés et al, 2010;López-López et al, 2014;Oppel et al, 2015). Bulgarian Egyptian Vultures migrate mostly through Turkey, Syria, Lebanon, Israel and Egypt to Africa, passing three "bottlenecks" on their way, but some of the Egyptian Vultures fly along the northern coast of the Red Sea to Yemen and Djibouti (Buechley et al, 2013;Buechley et al, 2018b;Bougain, Oppel, 2016), see fig. 2.…”