| Description |
This dissertation reviews the global status of all avian scavenging birds, including vultures, and synthesizes in-depth fieldwork on the endangered Egyptian vulture Neophron percnopterus in the Middle East and Horn of Africa. Chapter 1 provides a succinct review of the ecology, status, and importance of vultures globally. Chapter 2 evaluates what ecological factors contribute to extinction risk for all 106 avian scavenger species globally. Combined, these chapters show that vultures, which are the only obligate vertebrate scavengers, have experienced the most rapid decline in conservation status of any group of birds over the past decade and comprise the most threatened avian functional guild in the world. By quickly locating and consuming carrion, vultures outcompete and control problematic facultative scavengers (like feral dogs and rats), insects, and microorganisms. When vulture populations decline, carrion becomes increasingly available to other organisms, in a form of terrestrial eutrophication. Furthermore, vultures' highly specialized digestive systems efficiently eradicate diseases when consuming carrion, whereas facultative scavengers are more susceptible to contracting and transmitting diseases among themselves and to humans. Diet, geography, body mass, clutch size, and taxonomy are all strong predictors of extinction risk, but dietary toxins are by far the most important anthropogenic threat to avian scavengers. Chapters 3 and 4 build on extensive fieldwork in the Middle East and the Horn of Africa and satellite-tracking of the endangered Egyptian vulture to illuminate habitat preferences, migration routes, and critical sites to target conservation actions. In Chapter 3, Egyptian vulture habitat use was investigated within home ranges and core use areas. Overall, vultures strongly selected for anthropogenic features, including highways and powerlines in arid areas. In Chapter 4, the most important migratory bottlenecks and stopover sites for the Egyptian vulture on the Red Sea Flyway were identified. Discouragingly, none of the area within the major migratory bottlenecks was protected and only <13% of the area within the major stopovers was protected. This demonstrates a very concerning gap in the protected area network. Combined, Chapters 3 and 4 provide clear guidelines where investment is urgently needed to help conserve endangered vultures in the Middle East and Horn of Africa. |
