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Posts Tagged ‘vultures’

By Keith L. Bildstein, Ph.D., Sarkis Acopian Director of Conservation Science
Hawk Mountain Sanctuary

12 December 2016

We typically characterize vultures as gluttonous creatures, obligate scavenging birds of prey that engage in rough-and tumble feeding frenzies at large ungulate and pachyderm carcasses in the company of dozens of other “all consuming” vultures, scarfing up enough meat to last for several days.  And indeed, vultures sometimes eat so much food that they remain grounded for an hour or more after feeding for partial digestion to take place, before they are light enough to take off.  Having watched these birds feed for many years, I can tell you that all of this is true.  But watching vultures at so-called “vulture restaurants,” where humans routinely provide food, sheds light on an aspect of vulture feeding that goes largely unrecognized by the general public.

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The vulture restaurant at the Hoedspruit Endangered Species Centre in northeastern South Africa after dinner is served. Note the Marabou Storks in the foreground and the ling-necked African White-backed Vultures in the background. Hoodies are nowhere to be seen in the initial scrum.

In fact, some vultures are “finicky” as well as “voracious,” feeders; especially at vulture restaurants where daily meals are typical.  The world’s first vulture restaurant, in the Drakensburg Mountains of South Africa opened in the 1960s to help supplement the diets of local Bearded Vultures.  Today, vultures restaurants (bird feeders for vultures, if you will) are used to provide “clean,” lead-free meat to recently released California Condors in the American West.  Many of the restaurants are associated with ecotourism, serving a useful purpose in bringing vultures and people together.  One such restaurant at the Hoedspruit Endangered Species Centre near Kruger National Park in northeastern South Africa has been feeding wild vultures and other scavenging birds for more than 30 years.  The restaurant works well at attracting handfuls of Pied Crows and Black Kites, dozens of Marabou Storks and Hooded Vultures, and hundreds of African White-backed Vultures, the latter two of which are now Critically Endangered.

Earlier this month, University of KwaZulu-Natal post-doctoral student and Hawk Mountain research associate, Dr. Lindy Thompson, and I spent four days at the Centre near Hoedspruit trying to catch Hooded Vultures.  During that time we learned a lot about the finicky feeding behavior of the birds.  Our goal was simple enough: catch as many as three of the Hooded Vultures visiting the restaurant, and fit them with satellite-tracking devices that would allow us to monitor the movement ecology of the species, including information on how dependent individuals were on vulture restaurants in the region versus how much time they spent in the nearby Kruger National Park feeding on native wildlife, and how they interacted with other species in the region.

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Dr. Lindy Thompson, releasing “Don King” after his capture in February. Note his downy top-knot and relatively thin bill.

We already had caught and fitted 10 Hooded Vultures with tracking devices in South Africa, and two of our previously tagged birds actually showed up at the restaurant during our four days of observation, even though neither has been tagged there.  One of the two, Don King, had been caught at a private nature reserve 45 miles north of the Hoedspruit restaurant in February of 2016.  Don looked healthy enough, although he had lost his downy top-knot that led to its name.  The second tagged bird, Mopane, had been caught in Kruger National Park about 60 miles northeast of the restaurant in August of 2014.   It, too, looked quite healthy.

The two marked birds were joined by about 30 unmarked individuals that visited the restaurant daily.  Unfortunately we were unable to capture any of them.  We did snare several of the far larger African White-backed Vultures that clearly dominated the smaller “hoodies” at the restaurant’s offerings.   Hooded Vultures, it turns out, are finicky feeders when feeding in the company of White-backed Vultures, pecking at and gleaning only tiny scraps of meat with their small, thin bills, after the meat had been torn apart by the larger white backs during feeding frenzies.  By the time the hoodies got close enough to our traps, the snares we had set already had been pulled closed by the white-backs, making capturing the former all-but-impossible.

Lindy Thompson and Andre Botha of the South African Endangered Wildlife Trust will try to capture the hoodies at other feeding sites that attract fewer white backs.   Older elephant carcasses work well for this purpose, as they often continue to be visited by the more fastidious hoodies for several days after larger vultures, hyenas, and jackals have stripped most of the flesh from carcass.

The finicky feeding behavior of hoodies is well known among those of us that study the birds.  It appears that hoodies have instituted their own specialized feeding niche, one that involves “cleaning up” after the larger and less finicky species.  Although this makes hoodies a bit more difficult to capture, it is somewhat endearing as well.  As I see it, a vulture that cleans up after other vultures can’t help but be appreciated.

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aerial-view-of-dakar

Ariel view of Dakar, Senegal, a city of 3.5 million people and no traffic lights

By Keith L. Bildstein, Ph.D., Sarkis Acopian Director of Conservation Science
Hawk Mountain Sanctuary

11 November 2016

I began my studies of the world Critically Endangered Hooded Vulture in The Gambia in September of 2013, when colleagues and I placed four tracking devices on individuals in the exurbs of Banjul, the capital of that country.  Almost immediately thereafter, I thought about investigating their populations in Senegal as well.  Senegal, the western most mainland country in Africa is a much larger nation that completely encircles The Gambia–except for the latter’s small Atlantic coastline– and is an ecological  transition zone between the humid tropics farther south, and the Saharan desert of Mauritania to the north.

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The country-side along our survey routes

This year’s meeting of the Pan African Ornithological Congress in Senegal’s capital, Dakar, gave me the perfect excuse to follow up on this.  After attending the Congress and the important Second Pan African Vulture Summit associated with it, my colleagues and I tried to capture several “hoodies” in hopes of placing satellite tracking devices on them.  We also conducted three roadside surveys of vultures to learn more about the distribution of Hoodies and other vultures in the country.

Two mornings of trapping attempts at the Dakar Zoo produced no captures, and our attention on Sunday, the 23rd of October turned to leaving Dakar and traveling north to the small city of Louga, where three of us, Drs. Lindy Thompson, Rien Van Wijk, and I, planned to meet with a group of other European and African vulture biologists who also planned to survey vultures populations.

All went quite smoothly until we reached the town of Thies, Senegal, where our low-cost rental car overheated, forcing us wait on the curb for 6 hours for a replacement, which arrived only after darkness fell.  Driving at night in Africa is never easy–livestock, pedestrians, aggressive drivers, and potholes, see to that–and it was past midnight when we reached Louga, long after our colleagues had gone to bed.

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A Hooded Vulture perched near a nesting of Ruppell’s Vultures

A breakfast meeting the next day resulted in a decision to head southwest to the village of Dars, and then southeast on to the city of Mbaké, slightly more than 200 kilometers away, while surveying vultures en route.  Our colleagues would survey other routes.  We saw 169 vultures along the way, including 17 hoodies, 47 Ruppell’s Vultures, 71 White-backed Vultures and 34 Gyps vultures that we could not identify to species.  The route took us through open habitats not unlike those we survey in South Africa, except for the fact that all of the ungulates we saw on the way were domestic livestock (i.e., sheep, goats and cattle), rather than wild antelopes and other native mammals.  We spent the night in a small, and somewhat questionable, hotel on the outskirts of Mbaké, where a small red light over our beds confirmed our suspicions concerning the facility’s hourly rates of stay.

The next day involved following a meandering survey route to the city of Kaolack, which our travel guide referred to as the “armpit of Senegal. ”  Unfortunately, Kaolack turned out to be aptly named.  Our approach to the city included skirting the edge of a primary sewage treatment facility, which quickly cleared our nasal passages of the dust they had accumulated over the course of the day.  Our hotel and the opposite side of town proved to be something of an oasis, even if the highlight of its view-shed was an enormous

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A Hooded Vulture perched at the gate to our hotel’s parking lot in Dakar, Senegal

mountain of salt excavated from the adjacent hypersaline estuary. The day’s route included good looks at 46 Hooded Vultures, together with lesser numbers of Ruppell’s, White-backed, and Lappet-faced Vultures, along with several impressive multi-thousand bird flocks of White Storks.  Our third and final survey route, which took us back to Dakar, produced an additional 69 Hooded Vultures, a number of which were sighted in Dakar itself, together with smaller numbers of African White-backed and Ruppell’s vultures.  Although we were not sure of what to expect, the numbers of hoodies, in particular, were more that I imagined, albeit much less than 10% the density of those we had seen on similar surveys in The Gambia in 2013 and 2015, in more moist wooded habitats, about a hundred kilometers farther south.

Although we collected our data in a traditional fashion using our odometer to indicate the locations of all birds we sighted, we later entered our counts into the newly developed African Raptor Databank (ARDB).  The brain child of my good friend Dr. Rob Davies, the ARDB aims to ascertain the conservation status of raptors and their habitats across Africa, and to help build the local expertise needed to monitor these species in the future and implement a sound strategy for their effective safeguarding.

The ARDB will be completed in two phases. The first involves building a database over a period of five years (2013 – 2018). The second involves distribution modelling of each species in relation to the availability of its habitat and production of a conservation atlas for African raptors, online and hard copy. The project which received initial support from Hawk Mountain Sanctuary, is managed by habitat INFO, and is currently co-funded by The Peregrine Fund.

Given our initial experiences in Senegal, I plan to return early next year to conduct additional road surveys, as well as trap and affix tracking devices to two or more hoodies.

Importantly participants at the Second Pan African Vulture Summit I attended agreed to foster additional roadside surveys of African Vultures, the majority of which, including Hooded Vultures, are globally threatened or endangered.  Hawk Mountain plans to help in this effort every way possible, so that we can better assess vulture abundances and distributions, and, in so doing, formulate practical and effective conservation action plans.

Stay tuned as we continue to do so.

For information on how you can help, contact me at bildstein@hawkmtn.org.

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kerri-with-a-nestling

Hawk Mountain collaborator Kerri Wolter holding a tagged nestling Hooded Vulture in Olifants River Private Game Reserve, October 2013

By Keith L. Bildstein, Ph.D., Sarkis Acopian Director of Conservation Science
and Lindy Thompson, Ph.D., Hawk Mountain Research Associate
Hawk Mountain Sanctuary

10 November 2016

Yes, I admit it. We name our satellite-tracked vultures.

Some of our colleagues disagree with this, arguing that naming one’s study animals “personalizes” them in ways that make our observations less scientific.  But primatologist Jane Goodall and Nobel Prize laureate Konrad Lorenz named their study animals, and I have never doubted the scientific rigor of their work.  Naming animals as individuals makes their individual behavior easier to remember.  With more than 75 vultures tracked by satellite so far, numbers or alpha-numeric codes simply do not work as well, as names help to separate and categorize the birds in question and keep the stories of their movements in mind.

“Homebody,” a South African Hooded Vulture, is a case in point.

As a nestling, Homebody was fitted with a GSM satellite tracking device by Walter Neser and Kerri Wolter at the Olifants River Private Game Reserve in northeastern South Africa just west of Kruger National Park on the 19th of October, 2013.  Unfortunately, the unit never worked, and we decided to try to re-trap and refit Homebody with a new unit in the summer of 2014.  Trapping a vulture once is relatively easy.  We have caught hundreds of them.  Trapping the same bird twice, however, is a different matter entirely.  In 2004 we caught and placed data loggers in the body cavities of six Turkey Vultures to record their heart rates and core body temperatures.  The following year the birds needed to be recaptured and their data loggers removed to retrieve the accumulated data.  It took then graduate student and now Dr. Jamie Mandel, hundreds of hours during much of the next spring and summer to recapture four of the birds.  The other two were never recaptured.

 

nobuhle-with-homebody

Hawk Mountain trainee Nobuhle Mabhikwa holding the retagged Homebody in the Olifants River Private Game Reserve in June 2014

We had allotted a week of field time to recapture Homebody to replace its malfunctioning unit with a working one.  Three days unsuccessfully attempting to do so had us at wits end.  Hooded Vultures defer to larger African White-backed Vultures at carcasses, and Homebody, even though present at our trapping site, hardly ever got close to the carcass, let alone the snares that we had set around it.  But then something happened that one only dreams about.  We were late getting to our trap the fourth day of field work, and lo-and-behold Homebody and several other Hoodies were already at the site picking up small pieces of the bait that remained from the previous day.  Disappointed by their early arrival we drove our Land Rover toward the birds, flushing all of them into the air.  Miraculously, Homebody, after taking off to escape our approach, flew into a thorn bush and became entangled on one of the lower branches, which had slid between its body and the backpack harness we had used to attach the tracking device.  Within seconds we ran to the bush and hand-grabbed Homebody, disentangled it, and brought it back to base camp.  We then removed the malfunctioning unit and placed a new, fully functional unit on it.  Within 45 minutes of its miraculous recapture, we were celebrating our “lucky day” over a couple of beers.  A once-in-a-million event allowed us finally to satellite track the young vulture that had been tagged eight months earlier.

 

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Tracking device recovered from Homebody in October 2016

This alone makes for a great story.  But Homebody’s epic journey does not end there.  Last week–and more than two years later–we received an email from Colin Rowles, game warden at the Klaserie Private Nature Reserve.   Colin said a staff member on fence patrol had found Homebody dead at an impala carcass. When Colin went to collect the transmitter, he found that a Martial Eagle had consumed most of the Hooded Vulture.  Jackal tracks at the carcass lead him to believe that a jackal had killed Homebody.   We hope to place Homebody’s unit, which is still working, on another Hooded Vulture as early as this December.

 

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Homebody’s movements 2014-2016

Even though the story ended tragically for Homebody, we have placed similar units on other Hoodies, both in The Gambia and Ethiopia, as well as in South Africa.  Although several of these birds have died, most are still alive and transmitting important information.  The data we are now gathering will allow us to offer advice on how best to protect these birds, as well on the factors that most threaten them.  Costs associated in doing this are not inconsequential.  Homebody’s unit cost four thousand US dollars and download information from the unit cost us close to 600 dollars per year.  The information, however, is “priceless.”  Understanding the ecological neighborhoods of Critically Endangered Hooded Vultures is key to protecting them.

To learn more about our work with Hooded Vultures and other species of scavenging raptors, or want to support our field efforts financially, contact me at Bildstein@hawkmtn.org.

My next blog will describe our recent field work in Senegal, where Hooded Vultures remain very much in evidence.

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Skyline drive survey

Our survey vehicle on Skyline Drive in the Shenandoah National Park during our initial survey in the summer of 2005

By Keith L. Bildstein, Ph.D.
Sarkis Acopian Director of Conservation Science
Hawk Mountain Sanctuary

20 July 2016

I realize that I am running a risk with this column in talking about raptor monitoring. Indeed, when I begin to talk about monitoring, my audience often begins to doze off.  If I continue to talk long enough, some may even fall asleep.  Nevertheless, monitoring not only is a useful tool in raptor conservation; it is an essential tool.  When we in raptor conservation fail to monitor populations of birds of prey we often pay a steep and, in some instances, an irreversible cost.

Consider the current plight of the Indian Long-billed and Asian White-rumped Vultures, two species that 40 years ago ranked as the world’s most abundant large raptors.  Both species were then common and widespread throughout southeastern Asia.  When populations of both species crashed by more than 95% in Bharatpur, India in less than two decades in the late 1900s, the problem was thought to be pesticides.  But when similar reports were received for other populations elsewhere in these species wide ranges, a lack of earlier population monitoring made it difficult initially to ascertain the actual magnitude of the declines.

Two vultures that had once been so common that no one thought to monitor the sizes of their populations were now so uncommon that some conservationists were suggesting that they were in the “fast-lane” to extinction.  Half of a very large number is still a very large number, and by the time people were paying attention to these formerly species few knew what their once very large numbers had been.

Eventually conservationists learned the problem was an FDA approved drug, diclofenac, then in use on livestock.  Diclofenac, a non-steroidal anti-inflammatory substitute for aspirin that, while non-toxic to humans, turned out to be highly toxic to vultures in the genus Gyps.  But without proper population monitoring, we had reached a point where expensive captive breeding was necessary to reverse the trends.  Had we been monitoring these populations earlier, such extreme measures would not have been necessary.

Which brings me to my point.  Monitoring populations of raptors—even common and abundant species—is a critical component of practical and effective raptor conservation.  This is why Hawk Mountain decided to begin doing so with two species of common and widespread New World vultures in 2005.  As of late 2015, the Sanctuary has surveyed Black, Turkey, and other vultures in 23 locations throughout the Americas: from central western Canada in northcentral North America all the way south to Tierra del Fuego in southern South America and the Falkland islands in the South Atlantic.

Our surveys include both winter and summer counts totaling more than 24,000 miles of road counts across 14 United States, 4 Canadian provinces, and 6 central and South American countries.  Surveys are conducted by a driver and one official observer along secondary routes at 30 to 40 miles an hour on rain-less and fog-less days.  Counts begin at nine in the morning and end at four in the afternoon after and before most of the birds have roosted for the evening. In addition to Black and Turkey vultures, all other scavenging birds of prey are counted as well, including all other vultures, condors, and caracaras.

When we began the counts in 2005, the plan was to survey both Turkey Vultures and Black Vultures in representative areas across much of their geographic ranges and to redo the surveys once a decade in both winter and summer, so that populations of both migratory and resident populations of these common scavengers could be monitored routinely. Declines in numbers could be assessed in a timely fashion, and conservation action taken as necessary, before populations had declined catastrophically.

Black bear scvenging a road-killed deer

An unexpected “non-vulture” scavenger feasting on a road-killed deer along Skyline Drive during our second round survey in the summer of 2016.

Round two of our surveys began in early July 2016 when three Summer Field Experience Interns and I redid two day-long road counts in northern Virginia that were originally undertaken in the summer of 2005.  One of the routes was a mountainous 195-kilometer meander along Skyline Drive in the Park Service’s Shenandoah National Park and the northern-most section of the Blue Ridge Parkway.  The other was a 211-km route that followed the eastern shoulder of the upper Shenandoah Valley.  The numbers of vultures sighted were encouraging.  During two days of field work this summer, we counted a total of 253 Tukey Vultures and 14 Black Vultures, versus 124 TVs and 9 BVs seen on the summer 2005 counts.

Although this initial field effort was a modest one, we will ramp-up counts this winter to include 6 routes totaling 963 kilometers in western and central Panama, along with the two winter counts in northern Virgina.  Over the next five years, we plan to re-conduct all of our surveys from west-central Canada south to Tierra del Fuego.  We hope to find that all populations previously surveyed are stable of increasing.  However, if they are not, we plan to put conservation actions into play that will determine the cause or courses for the declines and begin work to reverse them.

Vulture perform important ecological services in the ecosystems they inhabit, not the least of which include nutrient recycling and reducing the likely spread of diseases including botulism, anthrax, and rabies.  Protecting their populations is a critical aspect of Hawk Mountain’s mission, and we plan to stay on top of this.  Our next surveys in Virginia are scheduled for December 2016.  We plan to redo our winter surveys in Panama in January 2017.  Once we have conducted them I will be in touch.

Between then and now let me know if you have any questions on this monitoring effort and how you can support the Sanctuary financially in carrying out this crucial part of our mission. Feel free to email me at Bildstein@hawkmtn.org or call me at 570 943 3411 ext. 108.

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keith releasing vulture may 2016

Keith releasing “Calm Lady” at the Buckeye dairy-farm trap site.

By Keith L. Bildstein, Ph.D.
Sarkis Acopian Director of Conservation Science
Hawk Mountain Sanctuary

27 June 2016

We’ve all seen the Gary Larson cartoons of vultures perched or soaring above one or two desiccated cowboys insightfully expounding on something comical.  Truth be told however, vultures are rare inhabitants of most of the world’s deserts.  Fortunately, this is not so in the Sonoran Desert of the southwestern United States and northwestern Mexico.

The Sonoran, a fascinating and ecologically rich region, is an important go-to place for vacationing Canadian and US snow birds, as well as home to 10 species of amphibians, 100 or so reptiles, 60 mammals, and more than 350 species of birds, including the world’s most northern breeding populations of Cathartes aura aura, a largely Neotropical subspecies of Turkey Vultures.  Investigating raptors at the limits of their geographic ranges has been a fascination of mine for more than 40 years, and this explains why I traveled to Buckeye, Arizona, 30 minutes west of Phoenix on Interstate 10 just before midnight on the night of Tuesday 17 May 2016.

Hawk Mountain’s Senior Research Biologist Jean-Francois Therrien and I landed at Sky Harbor Airport in Phoenix with an ambitious agenda.  The following day I would travel two hours south to Tucson to give a talk on our vulture work at the world famous Arizona Sonora Desert Museum, while at the same time Jean-Francois would hook up with Rich Glinski, the editor of The Raptors of Arizona, and try to catch vultures at a dairy facility outside of Buckeye.  Dairy farms are large in Arizona, and still-born calves would be the bait at our desert trap site.

Both Black and Turkey Vultures occur in Buckeye, and although we had begun our studies in the state in 2014 focusing solely on the latter, we have recently expanded the work to both species, as both were feeding, interacting at, and fighting over at the same nutritional resources, and fully understanding the feeding ecology of two species was only possible if we studied both of these competitors.

My talk at the museum was set for noon and a group of 40-plus museum workers and volunteers were eager to what I had to say as the museum had open an exhibit featuring both Black and Turkey Vultures a few months earlier.  Half way through the talk my mobile phone vibrated in my pocket.  Unfortunately, I ignored it as I didn’t want to interrupt the presentation.  That was a mistake, as Jean-Francois was calling from Buckeye to let me know that he and Ron had just caught and placed a satellite tracking device on an adult Turkey Vulture they had decided to call “Moo Moo,” the name the young daughter of our host blurted out when she first laid eyes upon it.  (Most of our trapping sites are on private land, and we always make certain to engage the land owners in all aspects of our field work, including watching us place tracking devices on the birds we catch and tag and helping us name them.)  The next phone call came two hours thereafter when JF called to let me know that he and Rich caught and tagged a second Turkey Vulture named “Gash.”  Both individuals, while quite healthy, weighed less than 70% of the Turkey Vultures we catch in Pennsylvania, which were members of the considerably more massive septentrionalis subspecies.  Needless to say we celebrated the day over dinner at a “wings” restaurant close to our motel.  We had brought four tracking devices with us, and after just one day of the four that we had allotted to trapping and tagging birds, we were half way to our goal.  The pressure was still on, but reaching our goal certainly appeared doable, and we were pleased.

Keith and AZ bird May 2016

Keith with “Calm Lady” at the trapping site.

We caught Turkey Vulture number three, “Calm Lady,” early afternoon the next day, and caught our fourth Turkey Vulture, “Early Bird,” before eight the following morning.  Four birds after a little more than two days in the field.  Not bad… not bad at all.  We took time off from the field the rest of day three while planning our work for the remaining two days we had scheduled to be in Arizona.  When we first started working in Arizona in May of 2014, our plan was trap and tag at least a dozen Turkey Vultures, and the four we caught in May of 2016 brought our total 15.  We also planned to conduct a series of six seasonal road surveys totaling 1,061 miles in southern and western Arizona.  The surveys would allow us to estimate the sizes of the wintering and summering populations there, providing us with critical information on regional numbers.

The next morning we set off a 166-mile road survey that began at Gila Bend and meandered through the towns of Ajo, Why, and Sells Arizona, while circling back toward Tucson.  We counted 63 Turkey Vultures and 3 Black Vultures along the way.  After overnighting in Tucson, we conducted a second, 152-mile survey that began at Three Points and continued south to Nogales on the border with Mexico, before turning north to Continental.  On that survey we counted 30 TVs and 1 BV along this route.  After finishing the survey we scurried back to Sky Harbor Airport in Phoenix to catch a red-eye flight back to Newark, New Jersey.  It was then onto Hawk Mountain by car, where we arrived mid-morning on Monday the 23rd.

Although we had spent but five days in the field, we had managed to catch and tag four new Turkey Vultures and had conducted two full-day roadside counts.  Our next trip to Arizona will be in January 2017, when we hope to catch and tag at least three Black Vultures and conduct as many as six road surveys.  Although the work—if you want to call it that—might seem tedious to some, for me and my colleagues it was as close to heaven as one comes in raptor biology…  a chance to catch up on all things “vulture” while trapping and tagging a few birds, surveying an important regional populations of two species, and getting the word out to the public about why we are studying Turkey and Black Vultures and what we are finding out about them.

In my next blog, which I hope to have out in several weeks, I will update you on our Arizona findings to date.

To learn how you can help support our studies, email me at Bildstein@hawkmtn.org or call me at 570 943 3411 ext. 108.

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The team pauses to take a self: From left, Jean-Fancois Therrien, Marc Bechard, Jennie Duberstein and Keith Bildstein.

The team, from left, Jean-Fancois Therrien, Marc Bechard, Jennie Duberstein & Keith Bildstein.

By Keith Bildstein, Ph.D.
Sarkis Acopian Director of Conservation Science, Hawk Mountain Sanctuary
May 26, 2014

I have just returned from field work on the northernmost population of North America’s southernmost race of turkey vultures, Cathartes aura aura, a diminutive and largely tropical sub-species that weighs only two-thirds as much as other North American turkey vultures.  Our field team was made up of Hawk Mountain Research Associate Dr. Marc Bechard of Boise State University, former Sanctuary trainee Dr. Jennie Duberstein of the U.S. Fish and wildlife Service, me, and Hawk Mountain’s Senior Research Biologist Dr. Jean-Francois Therrien.

Our work in the approximately 100,00-square-mile Sonoran Desert in southern Arizona which included placing satellite tags on both turkey vultures and black vultures, turned out to be—as  often is true of field work–full of surprises.  Our new trapping site at a pair of dairy farms on the outskirts of Buckeye, Arizona, southwest of Phoenix, was far better managed than many of the farms we had visited before, and its owners were gracious beyond belief. One of the potential trap sites offered little in the way of clear views of any traps we might put out, but a second site near a massive ossuary, or boneyard, proved to be perfect.

A bone pile provided an ideal trapping site in the Sonoran Desert west of Buckeye, Arizona.

A bone pile provided an ideal trapping site in the Sonoran Desert west of Buckeye, Arizona.

Our plan was simply enough to trap and tag six turkey vultures and four black vultures, conduct a few day-long roadside counts, and spend a day looking for several of the individual vultures we had tagged in May 2013. We had nine days to accomplish all of this and, as there was no rain in the forecast, the plan seemed quite reasonable.  In the past, our experience with trapping turkey and black vultures has been that the latter species is easier to trap than the former, in part because black vultures dominate turkey vultures at carcasses, and in part because of the black vulture’s more social nature (i.e., if you catch one you are likely to catch many).

But not this time around.

The first six birds we caught were turkey vultures!  Blacks, although relatively common in the area, rarely showed up at our trap site, and were more skittish than the turkeys. We did catch one on the sixth day of trapping, but decided to turn to road surveys on the seventh day, as the likelihood of trapping more black vultures seemed rather low.  Presumably most black’s in the area were feeding somewhere else, and unfortunately, we never found that location.

A perched turkey vulture along one of our survey routes near the ghost town of Ruby, Arizona.

A perched turkey vulture along one of our survey routes near the ghost town of Ruby, Arizona.

We spent the next two days counting vultures along two road-survey routes that covered more than 300 miles of Arizona secondary roads south of Gila Bend and Tucson Arizona, mainly in the Tohono O’odham Indian Reservation and the Coronado National Forest.  Unlike the counts we conducted in January, the routes were filled with single and small groups of turkey vultures, many of which appeared to be searching the roadways for road-killed carrion, including snakes. Overall, we saw more than 10 times as many birds as we had seen along the same routes in winter, suggesting that the bulk of the population migrates south from the region in winter.

We spent the final day in the field searching for the five vultures we had tagged last May. The first one we searched for was “Jennie,” a vulture that, having migrated about 250 miles into Mexico last October, returned to Arizona less than a week later and overwintered in the area south and west of Gila Bend.   Unfortunately, Jennie was roosting in the Barry M. Goldwater Air Force Range, a bombing range south of Gila Bend that was off bounds for us, and was feeding at a dairy farm west of Gila Bend that the owners would not allow us to enter.  The next three birds were roosting and hunting closer to Maricopa Arizona and we set out in search of them just before noon.

The last known location of the next bird, “Desert Rat,” took us to a roosting site in a nut grove across the street from a large dairy farm.  Although we did not actually see the bird, we did find a number of molted feathers under a nut tree, confirming the presence of vultures at the site.

Keith and Linda Wallace-Gray with her vulture namesake in May 2013.

Keith and Linda Wallace-Gray with her vulture namesake in May 2013.

The next bird we looked for was “Julie,” who had last been sighted over a recently cut  north of Stanfield, Arizona.  Although we failed to see Julie, we did see another tagged vulture, “Linda” feeding together with six other birds on a road-killed jackrabbit at the edge of the hay field. Linda’s transmitter had been “misbehaving” and was sending signals episodically, with the last fix being recorded more than a month earlier in early April.  She was close to where she was then, and our sighting of her helped explain the episodic nature of her signals.  Although her tracking device was still in place on her back, the antenna for it was missing, a fact that almost certainly explained the spotty nature of her signals.  Given that we had seen close to 100 birds the day we were searching for the tagged individuals, and that as many as 500 birds almost certainly were using the area, our visual sighting of Linda, albeit without her antenna, was like winning the lottery … a “grand finale” of sorts for our field work.

Our plans are to revisit Arizona next January, not only to finish our tagging efforts there, but also to conduct additional road surveys. Although we are but one year into our studies of Arizona’s Sonoran Desert vultures, we already have learned much about their ecology.  Equally importantly, we also have learned to expect the unexpected in this population, which gives me reason to believe we need considerable additional monitoring to understand this most-southern race of North America’s most common and widespread avian scavenger. So please stay tuned.

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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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