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Archive for the ‘tracking’ Category

20 March 2018

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

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The walk-in trap used to capture vultures at the Eliza Cove dump (Photo by Brandon Breen)

An e-mail from birding phenom Noah Strycker earlier this week reminded me just how interconnected our natural world of vultures really is.  Noah’s recent “big-year” book Birding Without Borders has made him an international birding super-star, and that is what brought him to Hawk Mountain for a fall lecture last autumn.  While at Hawk Mountain, Noah mentioned that he would leading a birding cruise in and around the Falkland Islands in March 2018, and I suggested that he be on the lookout for our color-banded striated caracaras there.  (You may recall that we have banded more than 1200 of these enigmatic raptors over the past eight years on the Falklands, and I was certain Noah would spot one or more of them on his visit.)  And indeed he did–R36 yellow, a juvenile we had banded on one island last summer, was seen by Noah almost 20 miles away on another island, a sighting that adds significantly to our knowledge of movement ecology in the species.

 

Noah, who was traveling on the M/V Ocean Adventurer, chartered by Quark Expeditions on a 33-day Atlantic Islands voyage from Ushuaia to Cape Verde, stopped for the day on March 13, and he and some others on the tour went to Gypsy Cove near Stanley to look for birds. They spotted two wing-tagged turkey vultures, a species we have studying and tagging in the Falklands since 2006.  One was tagged with number 10 yellow, the other with 37 yellow, two individuals that had been tagged as adults on two successive days in early July 2010 at a municipal garbage tip near Stanley.  That the two were still hanging around together more than seven years later is testimony to the longevity of the tags (take a look at them on the accompanying photos), as well as to the relationship of the two birds involved, both of which most likely roost with dozens of other turkey vultures on one of two small tussac islands near by.

Although we’ve had hundreds of reports of many of the 52 vultures we have tagged in the Falklands, Noah’s observations are the first in several years to report two birds simultaneously.

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A wing-tagged vulture at a municipal garbage tip near Stanley in 2008 (Photo by Alan Henry)

Somewhat surprisingly, most of the tagged birds have remained near Stanley (and the dump) confirming that human rubbish plays an important role in the diets of these birds.  I say “confirming” because a study of regurgitation pellets from turkey vultures collected by Amélie Augé of the South Atlantic Environmental Research Institute suggests a strong rubbish relationship.  Amélie collected her pellets in and around Stanley in 2015 and published her work in the journal Polar Biology in 2016.  Most of the regurgitation pellets she collected contained “anthropogenic debris,” including plastic, glass, paper, fabric, and/or aluminum in addition to more natural remains.  The relatively low human density of the Falklands (fewer than 3,000 on an archipelago the size of Connecticut) emphasizes the extent to which even small numbers of people can influence and contaminate the diets of raptors even on relatively remote areas.

 

I look forward to re-connecting with yellow 10 and yellow 37, as well as other wing-tagged turkey vultures on my next visit to the Falklands in August.  Assuming I do re-connect, I will let you know.

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Dr. Mike McGrady, Hawk Mountain Sanctuary Research Associate

13 Feb 2018

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An adult Egyptian vulture that was captured and fitted with a GPS transmitter in Oman.  Adult Egyptian vultures are mostly white from about 4 yreas of age, with black flight feathers.  Juveniles are brown, and subaduts are mottled, becoming ever whiter with age.  Photo: M. McGrady.

Like so many Old World vultures, the Egyptian vulture is globally endangered.  The threats to Egyptian vultures are pretty much the same as those that other Old World vultures face, and include electrocution, changes in food availability, direct and indirect persecution, targeted and inadvertent poisoning, and hunting for the black magic market.  Its endangered status and the threats notwithstanding, the Sultanate of Oman is a stronghold for Egyptian vultures, because it apparently has a healthy resident population and is a wintertime destination for a substantial number of migrants from farther north.

Since 2012, International Avian Research (IAR) has been working with the Environment Society of Oman (ESO) conducting research on Egyptian vultures in Oman.  That work has included surveys on Masirah Island (which was found to be home to the second densest breeding population in the world), monitoring numbers of vultures at landfills and satellite radiotracking of vultures.

Since 2015, the Greater Los Angeles Zoo Association (GLAZA) has, through Hawk Mountain Sanctuary, supported the work of IAR.  Two vultures were fitted with GPS radiotags in both 2015 and 2016, and two steppe eagles were fitted with tags in 2017—steppe eagles are also endangered; they breed mostly in central Asia, but migrate south (including into Oman) in the winter.

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An adult Egyptian vulture fitted with a GPS transmitter and ready for release being held by an Environment Society of Oman staff member.  Photo: M. McGrady

In January 2018, with the continuing support of GLAZA and Hawk Mountain Sanctuary, along with additional support from the Bernd Meyburg Foundation for Raptor Research and Conservation, IAR and its cooperators were able to capture 13 Egyptian vultures, 12 adults and one 2-year-old, and fit them with GPS tags.  Since then, the birds have been doing what vultures do.  Most of the vultures have spent their days ranging mostly in northeast Oman in the Hajar mountains and surrounding foothills. They have made regular visits to landfills, roosted in steep wadis in the mountains, and perched on high voltage electricity pylons. One bird has behaved a bit differently and has made at least two laps of the northern part of the country, seemingly always on the move.

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Adult Egyptian vulture in Oman in January 2018.  The GPS transmitter is fitted as a backpack and can be barely seen. Photo: M. McGrady

What do or will we learn from tracking, and how can this help conserve Egyptian vultures?  Well, the tracking of four vultures since 2015 has revealed that in Oman, Egyptian vultures suffer from electrocution and make regular use of landfills for feeding.  The data indicate that the vultures may move around in a way so as to keep tabs on the availability of food.  This, if you think about it, makes sense for a species that must find food that is not reliably available at all times.  The data further suggest that ongoing upgrades to waste management in Oman, reducing the number of dumps from over 300 to 12, may not have negative effects on vultures.  Indeed, improved waste management may make food resources safer for vultures and at the same time find benefits for human health, which is really good news.   IAR and ESO have also used the information to educate the public, including school children, about vultures and the important ecosystem services they provide as nature’s waste managers.

The data from these newly deployed tags should help the cooperating groups do more.  As we try to understand the ecology of the Egyptian vulture in order to conserve them, more data is important to the pursuit of science-based solutions.  From a public education standpoint, a complete “story” that includes more individuals over more years, provides a compelling case for conservation.  Also, with so many tagged adult birds, at least some are expected to be migrants, so new information on timing and routes of migration should be collected, and the location of breeding areas farther north can be determined. Such information is important in devising effective conservation strategies that span the huge range covered by migratory individuals, and it demonstrates the connectivity between breeding and wintering areas, which are sometimes separated by thousands of kilometers.

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Movements of 13 Egyptian vultures caught and fitted with GPS transmitters in Oman in January 2018.

 

If you want to keep up with this effort, IAR posts information every so often on the project at https://egyptianvultureoman.blogspot.co.at/ .  If you would like to support this project, please do so through an earmarked donation to Hawk Mountain Sanctuary.

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By Adehl Schwaderer, Hawk Mountain Conservation Science Trainee

03 Jan 2018

 

As a Hawk Mountain Conservation Science Trainee, you have the opportunity to be a part of many influential experiences, including counting migrants as they pass North Lookout and educating visitors about the importance of raptor conservation. But the experience that I have learned the most from this autumn was working with my fellow trainee Zoey Greenberg on our black vulture movement ecology project. This blog is part two of our vulture series so be sure to check out part one to gain a complete understanding of our project.

 

The plan was to locate three black vultures, Versace, Gifford, and Hillary, based on their recent GPS locations and observe what the birds were doing at these locations. To be honest, I wasn’t sure what to expect. I was excited to get started and gain new field experience, but no one had ever attempted groundtruthing with this species before, and it is still a new concept. We accepted this challenge with enthusiasm but were anxious about getting results. In the end we knew that no data would still be valuable information, however who doesn’t want groundbreaking results from their first ever field study?

 

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Versace perched on a barn in the Kempton Valley, notice her wing tag and antennae of the telemetry unit.

Thankfully, our first day in the field was a success! Zoey and I followed Versace’s movements from the previous month, which led us to a large roost of black and turkey vultures in the Kempton Valley. We were ecstatic, and from that point on, we were on a roll! Throughout the next three months we kept up our tracking efforts and found many more roosts (some permanent and some temporary), observed interesting behaviors, and made an effort to trap and tag these birds. By doing all of this, we were able to confirm some of our suspicions. However, we also discovered things we did not expect.

 

One of the suspicions we were able to confirm was that black and turkey vultures more often than not share the same roost sites. These two species have very different tendencies when searching for food, feeding, and perching, but that did not stop them from co-existing at the same roosting sites and air space. We also suspected that the vultures would use some roosts more consistently than others depending air temperature, trees available, and proximity to their next meal. We determined what each roost site was being used for, as well as observed a shift in preferred roost locations and species composition as winter set in and turkey vultures began migrating south.

 

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Turkey vulture trapped and tagged in Kempton Valley by Adehl, Zoey, and David Barber. 

We found the most unexpected results attempting to trap “our” black vultures. We enlisted the help of Hawk Mountain biologists, David Barber and Jean-François Therrien, who both have extensive trapping and tagging experience with vultures and other raptors. The goal was to capture and wing tag a substantial number of the black vultures we followed around in the Kempton Valley.

 

 

To do so, we staked down road kill (a vulture delicacy) at several roost sights we had determined were used mainly for feeding. Once the bait was staked, we placed noose traps made of fishing line and parachute cord in a diamond around the carcass. Once everything was in place, we would wait for the vultures to descend on the meal and consequently get their feet stuck in our traps—a process that does not harm the birds).

 

That is exactly what we did. We waited… and waited… and waited to no avail. The first site we chose to bait was seemingly perfect. There was already an area on the property where the landowners frequently discarded rotting vegetables and meat scraps. In addition, dead trees and conifers, which provided many roosting options for the birds, surrounded the dump.

 

However, shortly after we began baiting, two unwelcome visitors decided to join the flock: an adult and immature bald eagle. Now you may be thinking, “Wow! How amazing you get to observe vultures and the majestic bald eagle in one place!” Well, you would be wrong. We learned immediately that vultures and eagles do not enjoy sharing the same air space, or the same dining room table for that matter.

 

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Adehl holds the trapped and newly tagged turkey vulture.

We are confident that this interaction caused us to be unsuccessful in trapping vultures at this trap site, and the second area we chose to bait and trap. As soon as the eagles were seen at the roosting areas, black and turkey vultures were not seen roosting in those locations again during our observations. We did not expect this to occur because in other locations, like the Conowingo Dam in Maryland, eagles and vultures co-exist in the same feeding sites with no apparent issue. We believe the higher tolerance in these areas could be due to a larger food source with enough to go around for everyone, meaning that there is no need to initiate a food fight. The availability of only one carcass at our bait sites and providing large carcasses that were more easily discovered could have been the reason that the vultures and eagles in our study did not get along at our sites. However, all was not lost! In the end we did manage to trap and tag one turkey vulture, which was a very valuable learning experience for Zoey and myself.

 

 

Ultimately, I was able to witness unique behavioral patterns through this opportunity that will stick with me the most. I will never forget the breezy autumn morning when over twenty turkey vultures performed aerial acrobatics on a freshly plowed hill between bouts of picking through the soil with their bills and talons. Nor will I forget standing in the pouring rain, watching more than forty black vultures run across the bars of an information tower with their bills clapping and wings spread wide.

 

Zoey and I learned so much by only taking the time to stop and observe, and we are excited to see what else others that take the time to do the same will discover.

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By Zoey Greenberg, Hawk Mountain Conservation Science Trainee

21 Dec 2017

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Female black vulture named Donald over a quarry during September of 2016 near Palmyra, PA.

The tires crunched on gravel, and I shut the engine off. We had entered vulture country. With scope, data sheets, and binoculars in hand my project partner, trainee Adehl Shwaderer and I walked carefully up the gravel road as we scanned the tree tops for hunched silhouettes or soaring shadows. This was our first foray into the Kempton Valley, east of Hawk Mountain, in search of black vultures (Coragyps atratus). Our expectations were not high. However, we had innovation on our side: we were testing a method called “groundtruthing” to better understand the movement ecology of several vultures that had been tagged with satellite transmitters by Hawk Mountain scientists. After investigating their movements in Google Earth, we had discovered interesting patterns including an individual who spent time near quarries, and another that seemed to prefer cities. The problem was, we didn’t know why.

 

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Some tools used for groundtruthing method: laptop, smartphone with hotspot, and a vehicle.

Groundtruthing works like this: we, the field researchers, embark into the field with an internet hotspot and laptop in tow. We look up the locations of tagged vultures on an online database called MoveBank.org and then drive to meet individual birds and watch their behavior. By combining technology with old-school methods, we are able to gain visual access to black vultures and unveil mysteries about their movements that remain when we rely exclusively on satellite tracking data to explore patterns. As I became more comfortable with groundtruthing, I realized that the beauty of the method exists in its simplicity, utility, and the truism that even in this day-and-age there is no substitute for in-person observation.

 

A wonderful realm of study exists when we move beyond discovering where birds are, and incorporate studies that investigate why. Black vultures provide irreplaceable ecosystem services for us through their removal of carcasses that can carry harmful diseases. However, due to their curious nature and adaptability, they are often involved in conflict with humans that can result in noise-hazing, shooting, and other forms of human persecution. Therefore, investigating their movement patterns is necessary.

 

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Versace’s movements within the Kempton Valley, November, 2017.

At the beginning of our project, we relied on the signals of three birds, Gifford, Hillary, and Versace. (Donald, who turned out to be an adult female, flew to Washington DC after being tagged. We have not heard from her since.) By following these individuals, we discovered three night-time roosts within the first week and I feel confident that any bystander watching our first roost discovery would have been convinced we’d won the lottery. A silent performance of spastic jumping, “air-fives”, and the spontaneous creation of a vulture dance quickly occurred before we got back to business and counted the birds.

 

In the weeks that followed, we experimented with various observation techniques and read multiple papers on roosting ecology, black vulture foraging strategies, and behavioral study methods. We talked vultures at breakfast, lunch and dinner. We bored our housemates at the trainee residence with discussions on the most pungent types of road kill and the antics of our favorite birds. We filled our brains with vultures, and above all, became true detectives through a process of trial and error that taught us the value of being innovative in the field. Those first weeks were memorable, solidifying in me a hunger for scientific questioning.

 

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Zoey with a tagged turkey vulture.

There was an additional aspect to this project that I found consistently rewarding: the opportunity to speak with landowners in the Kempton Valley. Many of the roost trees preferred by “our” vultures were on private property, and in addition to observing the birds, we were looking for optimal trapping sites near already-established roosts in hopes of catching wing-tagged birds. This would provide us with information on associations among individuals. However, our trapping method entailed staking road kill to the ground and waiting for vultures to arrive while we waited nearby. In general, people aren’t thrilled about the prospect of hosting dead possums in their backyard. Nonetheless, we were rarely told no. Even landowners who professed a hatred of vultures were open and willing to hear our reasons for loving the birds, and eventually developed a tolerance of their own.

 

Vultures are hard to sell, and they do have some less-than appreciated habits, such as defecating on cars and toying with the rubber on windshield wipers. However, every “bad” habit has an explanation. For example, vultures are scavengers, meaning they rely heavily on maintaining strong neck muscles for tearing and pulling apart carcasses. To a vulture, rubber is an irresistible training opportunity to both strengthen their neck and satisfy their characteristically curious nature. It became clear that explaining to people why the birds were choosing their property provided them with a new dimension of understanding. This makes groundtruthing not only important for answering scientific questions, but also for enhancing a culture of appreciation around birds that struggle to gain respect. After all, our home ranges overlap with other species, and as such, perhaps we have a duty to critically evaluate our collective perception towards all of our neighbors, including vultures. After spending this season in the field, I am convinced that the Kempton Valley is a perfect place to start.

 

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Conservation science trainees Adehl (left) and Zoey (right) embark on an early morning search.

So what’s next for the vulture detectives you ask? Our field tested method of groundtruthing will be used to fill in more gaps in places with tagged vultures, contributing to our knowledge of why the birds go where they go. Ideally, this information can then be directly applied to informing locals, politicians, conservationists, biologists, and other groups affected by or connected with vultures in their region. As for Adehl and me, early morning roost searches and tactfully placed road kill may remain in both of our futures. There are few sights that compare to a group of dew-covered vultures eyeballing you from above as they slowly swivel their body to absorb the sun’s first rays. With a sight like that there’s only one outcome: once a vulture detective, always a vulture detective.

 

To learn more about our interesting findings, stay tuned for Vulture Detectives: Part 2 written by Adehl Shwaderer.

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By Katie Harrington, Hawk Mountain Graduate Student and Former Conservation Science Trainee

10 May 2017

This March I watched three Johnny Rooks feeding in the beached kelp wrack adjacent to a falling tide, with an endless symphonic bray of gentoo penguins in the background. Early afternoon seemed to be the rooks’ final push, as it were, to fill their tanks before tucking in for a late afternoon nap.

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A fresh bird with a fresh band; welcome to the world K28 Yellow.

While the adult and two juveniles raked with resolve, another rook, band K28 Yellow, walked to within three feet of me. Unlike times before though, it wasn’t staring at me. K28 Yellow, whose plumage betrayed it’s youth–a fledgling, perhaps having only left the nest just six weeks prior– approached a piece of dried “basket kelp” tucked between driftwood and beach cabbage. Without hesitation, K28 “kick-boxed” the kelp and, clinging to the fibrous ball, fell and rolled onto its back. I watched, trying not to laugh, as it pecked at, clawed, and rolled around with the basket for five minutes, doing what I could only call playing.  The raptor, a close relative of the Peregrine and other falcons, reminded me of a puppy consumed with its chew toy.

While extensively studied in mammals, there are far fewer recognized examples of avian play, particularly in raptors. Among birds it is best documented in corvids (e.g. crows and ravens) and parrots.  Raptor examples include object manipulation by a captive-raised goshawk, an observation of a wild marsh hawk playing with its horned lark prey, and aerial acrobatics of bald and imperial eagles.

It’s worth pausing here in light of the genetic revelations of the past decade that place caracaras and falcons next to parrots in the tree of life, rather than alongside hawks and eagles. In fact, when reading about the kea, a parrot found only on New Zealand, you could almost replace their species name with “Johnny Rook” and have it read seamlessly. They, like rooks, are highly social, bold, curious, opportunistic foragers that feed on insects just as readily as seabirds and carcasses. And they play, extensively, with other keas and with inanimate objects. These qualities, along with their approachability, make both them and the Rooks the perfect candidates for studying play in the wild.

This occasion of watching a rook play wasn’t an anomaly. Over the two months I spent on Saunders Island this past austral summer (Feb-March), I watched multiple solitary and social play events across all ages of rooks. One time, another recently fledged bird and an adult played with a sheet of plastic stuck in the sand dunes, again rolling onto their backs as they kicked and pulled. For others, old carcasses, long picked clean became ceremonial tug-of war tools. Given the intensity of local fishing, there were also plenty of cast lines that washed ashore, frayed, half buried, just begging to be played with.

Are the birds learning about their environment, building social bonds, or honing  predatory or stress responses? At this point, we don’t know. Fortunately, our long-term banding project allows us to track this behavior in specific individuals, creating an unprecedented opportunity to understand the adaptive significance of this behavior in a raptor in the wild. And let’s be honest, what’s more endearing than watching a predator kick its talons up and play?

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Dr. Keith Bildstein about to release one of the northern breeders this January.

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

17 March 2017

Most studies of bird migration focus on the movements of birds that ornithologists refer to as “complete migrants,” species whose global populations evacuate their breeding grounds each year while traveling to geographically distant wintering areas.  Although Arctic Terns, Black-and-white Warblers, and Broad-winged Hawks, along with a small percentage of other species of migratory birds, do follow this pattern, most migratory species of birds are “partial migrants,” species whose populations include both sometimes-migratory and non-migratory individuals, and whose migratory populations sometime overwinter in areas already occupied by non-migratory members of the same species.  It turns out that partial migration is a lot more complicated than complete migration, and although the former is little studied compared with the latter, its complexity makes it a lot more intriguing, as well as a lot more challenging, both to investigate and to understand.

New World Turkey Vultures are a good example of partial migrants, with some populations consisting entirely of migratory individuals, whereas other populations consist of both migratory and non-migratory individuals, and still other populations consisting entirely of non-migratory individuals.  The degree to which different populations of Turkey Vultures interact, and the effects they have on each other is not well known.  One place where such interactions have been explored is in the Llanos, the enormous freshwater wetland of central Venezuela, where Turkey Vulture migrants from western North America, which are larger and more massive than the region’s non-migratory, year-round residents, displace the latter from the best available habitats and gain weight after their arrival while the supplanted residents simultaneously lose weight.  Indeed, the so-called Llanos “residents” appeared to “migrate reciprocally” to avoid competing with of the larger North American birds.

But what happens in areas in which some breeders migrate south in autumn, whereas other stay put, while still others from more northern breeding sites migrate into the region and over-winter there?  Such is the case in the Sonoran Desert of southwestern Arizona, where members of the breeding population include both migrants and non-migrants of the aura race of Turkey Vultures, whereas as the winter-only individuals are migrants from the larger and more massive meridionalis race from farther north.  (Note: There are six subspecies of Turkey Vultures, three that breed in North America, along with two that breed in Central America, and three that breed in South America.)

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Keith and Hawk Mountain Sanctuary Senior Researcher Dr. Jean-Francois Therrien fitting a satellite to one of the norther breeders this January.

We began satellite tracking members of the Sonoran Desert breeding race in 2014 and have followed the movements of nine birds since then.  All but one have proved to be migratory, with some individuals overwintering consistently in Mexico, whereas other have overwintered consistently either in Guatemala, El Salvador, Panama, or Colombia.  In late January of this year my Hawk Mountain colleague, Dr. Jean-Francois Therrien, and I traveled to our tapping site outside of Phoenix and successfully trapped two winter-only individuals of the meridionalis race of Turkey Vultures.  Although we don’t know exactly where these two breed, as of early-March one was on Vancouver Island in south western most Canada, and the other was in Death Valley California in late March, with both north of their Arizona trapping site.

Tracking the movement of all of these Sonoran birds for several years will allow us to determine if the northern breeders crowd out the smaller year-round residents from Arizona, and if so, whether or not the smaller southern migrants leave in autumn in advance of the arrival of the larger northern migrants and time their returns to avoid the departing northern migrants in spring.

Although this may seem a bit esoteric to some, understanding the extent to which the two subspecies interact in the Sonoran Desert has important implication for conservation.  Suppose, for example, that in Arizona the larger northern breeders consistently dominate the smaller southern breeders.  If so, the size of the former’s populations could limit the size of the latter’s, particularly in winter when food may be limiting.  If so, the fate of the latter would be affected by the fate of the former.  Thus, if global change were to affect the former–either positively or negatively–the latter might “respond” as well, albeit indirectly, in-kind.  Although, all of this remains highly speculative, the extent, if any, to which populations of the two races merits examination, and I very much look forward to doing so over the course of the next few years.

I will keep you posted of the arrivals and departures of both our “northern” and “southern” Arizona migrants this summer.

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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.

 

satellite-united-recovered-from-homebody

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.

 

homebody-movements-2016-10-27

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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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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