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Archive for October, 2013

By Corinne Kendall, Ph.D.
Hawk Mountain Research Associate

Corinne with hooded vulture

Corinne with hooded vulture

Having recently completed a Ph.D. studying the movement of three of Africa’s threatened vultures – Lappet-faced, African white-backed, and Ruppell’s – in Kenya with the support of Hawk Mountain Sanctuary, I was thrilled to have the opportunity to learn about the movement of one of Africa’s most understudied raptors, the hooded vulture.

I tend to think of hooded vultures as the “chickens” of the vulture world thanks to their tiny beaks and small body size. Hooded vultures are unique in that they generally specialize on the tidbits left behind by other scavengers and have even been known to eat the feces of predators and other animals.

Having only handled a single hooded vulture in Kenya, I couldn’t wait for the opportunity to gain further first-hand experience with these gentle and tiny vultures. So when we caught our first bird, I wasn’t surprised to find that it lay relaxed in my arms while we attached the satellite unit. The juvenile bird was covered in downy feathers, particularly dense along its chest, and had beautiful long eyelashes that it batted gently as it looked up at us. Blood drawn and unit attached, it was quickly released but choose to stick around and stood to take a good look at us before finally flying back to join the impressive number of birds (close to 50) that had gathered in the trees around our bait.

Questions to be answered by this movement study of hooded vultures abound. As someone who has tried to understand how so many species of vultures can live together and why some are more threatened than others, I’m particularly interested to see how they compare to the birds we have previously studied.

Hooded vultures are certainly smaller in body size, but does that mean they will have a smaller home range than their larger cousins, like the Ruppell’s vulture, who can travel over 200,000 km2 in a year? In Kenya we have seen the importance of protected areas in shaping vulture movement for other species, but in West Africa where the parks are smaller and more scattered, how will the hooded vultures use the protected area network? If hooded vultures are spending more time near people in West Africa, as they certainly seemed to in The Gambia, will they have smaller range than they do in Kenya and South Africa, where they tend to be found in more natural habitats?

With our first week of data in hand, the excitement is gaining as we gather insights into the habits of these peculiar birds. But only with time, and the help of the four satellite tagged individuals, will we begin to understand what it is these birds need to survive and why they are so much more vulnerable in some parts of the continent than in others.

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Keith holding a satellite tagged juvenile Hooded Vulture

Keith holding a satellite tagged juvenile Hooded Vulture

By Keith L. Bildstein, Ph.D.
Sarkis Acopian Director of Conservation Science
3 October 2013

As readers of this blog know all too well, Africa’s vultures are in trouble … big trouble. Nine of 11 species are “Red Listed” by the International Union for the Conservation of Nature, either as Near Threatened, Vulnerable, Endangered, or Critically Endangered, and many regional populations face the immediate threat of extirpation. Hooded Vultures, whose movement ecology Hawk Mountain decided to study in detail in 2012 are no exception (the species is now considered Endangered globally), and many populations in both East Africa and South Africa appear to be in steep decline.

With critical support from the Wallace Research Foundation and North Star Science and Technology, Hawk Mountain and its colleagues in Africa are in the process of placing satellite tracking devices on individual Hooded Vultures in many parts of its African range. Indeed, if all goes according to plan, two or more tracking devices will be placed on Hooded Vultures in Ethiopia, Kenya and South Africa later this autumn.

Earlier this week my colleagues and I placed four units on Hooded Vultures (three juveniles and one adult) in The Gambia, a small West African nation surrounded on all sides except for its Atlantic Coast by Senegal. The work went extremely well and what I learned during my short visit to this African nation has lifted my spirits considerably.

Clive Barlow, an intrepid Gambian colleague and new friend, has been watching Hooded Vultures for decades in The Gambia, and his willingness to partner with Hawk Mountain allowed me and raptor specialists Dr. Marc Bechard of Boise State University and Dr. Corinne Kendall of Columbia University to conduct a series of road surveys in The Gambia, as well as catch and tag four individuals for satellite tracking. Clive who has worked in The Gambia as an ornithologist for 30 years, co-wrote the book on Gambian birds with Dr. Tim Wacher ZSL UK (Barlow, et al. 1997. A field guide to Birds of The Gambia and Senegal), and l laid the ground work perfectly.

Our first day on the ground included meeting our counterparts inthe Gambia Department of Parks and Wildlife Management, including its director Mr. Momodou L. Kassama, and explaining how we intended to proceed with our work and discussing the details of our permit. The second day included baiting a trap site that Clive had been “pre-baiting” for weeks and sitting back and waiting for the vultures to arrive.

And arrive they did.

Part of a large communal ground roost used by Hooded Vultures near the national airport in The Gambia.

Part of a large communal ground roost used by Hooded Vultures near the national airport in The Gambia.

We placed the bait–a recently killed domestic chicken–out and set the trap at 9:30 a.m. Within two hours our first birds (two adults and a juvenile) dropped down and within a minute, we had trapped our first two Hooded Vultures: an adult we named Makasutu after the privately protected forest we had caught it in, and a juvenile named Mandina-Gambia, after the Mandina Lodge, the ecotourist facilty we used as base camp. In addition to placing tracking units on the birds, we collected a small amount of blood from each of them for sexing and eventual genetic analysis, weighed them, and released them back into the wild in short order. It is unusual to trap two birds simultaneously so we were confident about our great start.  The next day we caught and tagged another juvenile in the Department of Parks and Wildlife Management’s Abuko Nature Reserve about 20 kilometers away, and named it Abuko in honor of the reserve. We also conducted the first of three roadside counts along a 24-kilometer route during which we saw an astounding (at least to us) 654 Hooded Vultures. Two days later we caught a second juvenile at Abuko and named it Tan Hoodie … “Tan” meaning “vulture” in the local Wolof language. Two additional road surveys later in the week suggested that in western-most Gambia, at least, populations of approximately 20 birds per square kilometer were the norm, which is far more than any of us had anticipated. Indeed by comparison, I had only a few dozen hoodies during five weeks of work in the Masai Mara region of southern Kenya in 2011 and 2012.Why the birds are doing so well in The Gambia remains something of a mystery, but studying the movements of these birds, and comparing them with those of birds in decline populations elsewhere promises to be an important first step in understanding the species ecology in different parts of it range, which, in turn, should help us better assess where the threats to this species lay, and how we might better design effective strategies for their survival.

Several adult Hooded Vultures at a trapping site.

Several adult Hooded Vultures at a trapping site.

Unfortunately, one week in the Gambia is but a tiny step in the right direction.  Additional work, including satellite tagging many more birds is needed. The task will not be easy but for the rationale for doing it is plain. If we don’t learn more about this species ecology and behavior, and we don’t learn it quickly, we may lose ecologically functional populations of this the most widespread of all African vultures.More field work will require more funding, of course. But my trip to a haven for Hooded Vultures has only served to rejuvenate my enthusiasm for this important project. The loss of ecologically significant populations of vultures in southern Asia has brought with it dramatic increases in scavenging feral dogs, which, in turn, has resulted in rabies in humans skyrocketing in many places. We simply can’t afford to let that happen in Africa, the center of Old World Vulture diversity.Hawk Mountain plans to be in this good fight for the duration. If you want to help Hawk Mountain in this truly worthwhile effort, please contact me.

For information about how you can help, contact: mailto://bildstein@hawkmtn.orgor 570-943-3411 x108.

Acknowledgements:  Mawdo Jallow & Lamin Sanyang (DPWM) , Lawrence Williams , Linda English & staff Mandina Lodges @ Makasutu, Dr Tony Fulford & Dave Montrieul (road surveys & photographs)

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