Catch A Vulture By The Toe
February 10, 2016
I wake up to a heavy rain—the droplets fall on a tin roof and I’m immediately aware of my surroundings. Today is the final day of preparation. I’m in Iringa, a town in central Tanzania, and I’m picking up the final supplies for a week of camping near Ruaha National Park. We need all the usual things—canned food, nuts, batteries, flashlights, tent stakes and, of course, water. But for our trip we also have some unusual items to pick up—unscented dental floss, aquarium tubing, Teflon tape (imagine a long thick rope), 250-pound strength fishing line, parachute cord and, most importantly, 70-gram solar-powered satellite telemetry. These are the essentials for trapping and tagging the African White-backed Vulture, one of the world’s fastest declining but most important birds.
Vultures are strong, so our materials need to be as well. Parachute cord and fishing line are strung together to make nooses, which are large black loops that will be laid along an animal carcass to catch the feet of the vultures. Teflon tape is strong and durable and, with an aquarium air hose inside, can also be flexible. I have used this to fashion a vulture “backpack” that will be used to fasten our satellite tag to the bird. Dental floss, another strong and waterproof material, is the ideal sewing material for the job and will help when tying the final strap on to the bird.
Why all the fuss over the animal kingdom’s ugly eaters of the dead? Vultures are nature’s garbagemen (and garbagewomen). They help keep the environment clean by eating disease-ridden and sometimes rotting dead animals. They may not be the most charismatic or beautiful animals, but we desperately need them to maintain a healthy ecosystem. In fact, the near-extinction of vultures in India led to thousands of human deaths as feral dogs took over as the main scavengers, underwent a population explosion and began to spread rabies. Vultures are also disappearing throughout much of Africa, leading to several species now being considered Endangered or even Critically Endangered (see ftE NewsClip: Six African Vulture Species Uplisted). In Kenya, where I did my graduate studies, vultures have declined rapidly due to the poisoning of carcasses, usually done by pastoralists trying to kill the lions and hyenas which occasionally kill their livestock. Ending poisoning there will be incredibly complicated and will require government bans on key agrochemicals and the resolution of human/wildlife conflicts. Sadly, this may be impossible in the timeline needed to save vultures.
Southern Tanzania represents our last hope for African vultures, but we know almost nothing about vultures here. How are their populations doing? Is poisoning a big problem here as it is elsewhere in Africa? What other areas do southern Tanzania’s vultures use? There is hardly a vulture in Africa that doesn’t call at least two, if not three, African countries home, thanks to their large ranges. (Kenya’s vultures can range across Tanzania, Sudan, and Ethiopia as well as across almost all of Kenya). Unfortunately, these large ranges also mean that, while vultures may be safe in one country, they could still be dying when they travel to another. So it is critical to know where they go. And that is why we are here. If we can catch a few vultures and attach satellite transmitters to them, we will get a glimpse into their private lives and begin to scratch the surface on these and many other questions. This information will be critical to protecting vultures in southern Tanzania.
February 11, 2016
Vulture trapping takes patience, persistence, and luck. Despite not having any real predators and being extremely inquisitive, vultures can be surprisingly cautious. After setting up our nooses on a fresh carcass, we sit and wait about 50 meters away. For the next several hours our job is to observe what comes to the carcass and, when something arrives, to watch carefully to see if it is trapped. Because of the tall grass and muddy roads, we have chosen to trap next to a currently unused air strip on the edge of Ruaha National Park. This is one of the few areas reliably accessible this time of year as the particularly heavy and early rains (it is after all an El Nino year) have washed out many roads and even a few bridges. So we sit next to this long dirt track and wait and watch.
Unfortunately neither the weather nor the birds are cooperating today. We have some drizzles throughout the morning which limits the number of vultures flying. Perhaps as a result, we see few vultures in the sky, and certainly none at our carcass.
February 12, 2016
We are out again first thing in the morning with carcass and nooses ready for birds to begin scavenging and, hopefully, for us to begin trapping. At first we are mostly watching the air. Birds will fly over and carefully examine the situation from the sky before choosing to land. A vulture or scavenging eagle must determine if there are any predators still lurking and protecting their prey before risking their lives and coming to the ground.
A beautiful black eagle called a Bateleur flies over. These birds are easily identifiable by their angled wings with the deep white band along the edge, and by their red feet and beaks. I can see the eagle angle its head to examine what lies below it. It leans from side to side as it soars, giving it a rather acrobatic look in flight (hence the name Bateleur, which means acrobat in French). After careful assessment, the Bateleur flies on. At first one might find this disappointing, but I know the drill. This eagle is clearly interested in our carcass, but it must disguise its interest so as to prevent other birds from following it in. You see, vultures and other eagles spend much of their time watching each other and looking for Bateleurs or other birds descending on a carcass. Because the Bateleur is considerably smaller than a vulture, its opportunities to feed will be maximized if it can land without any other birds noticing. So it passes by the carcass the first time but will come back when it feels more confident that it is not being watched.
Indeed, about 20 minutes later our eagle returns. No other birds have passed overhead since it left, so the skies appear to be clear. The Bateleur lands and quickly begins feeding by pecking and pulling at small pieces of meat. We watch patiently. Although this is not the bird we want to catch, it might help bring some vultures to the site as it feeds. We will also need to go get it if it does pull a noose around its rather large and sharp talons.
After nearly thirty minutes of feeding, the Bateleur has had its fill. It begins to walk away only to find that its foot is caught. We see flapping at the carcass and drive quickly to free our unintended guest. As we near the carcass, the Bateleur is able to free itself from the noose and take off. This is not a problem since we aren’t trying to catch this species anyway. We reset the nooses and go back to watching. But after a long day, few vultures fly over, and no other birds land at our trap.
February 13, 2016
Today we have moved locations. After two days at the airstrip with minimal vulture activity, we have to question whether or not this area was one that vultures use regularly. So we have moved to a camp just outside of Ruaha National Park. In the wet season rain isn’t the only problem. The other issue is tall grass. Therefore, we decided to set up in an area next to an elevated camp where we will be able to look down on the carcass. It is an exciting morning with nearly 35 White-backed Vultures overhead but, again, none on the ground. We are again left searching for new spots to try trapping.
February 14, 2016
Today we set up our carcass and nooses underneath a small Baobab tree. We used our vehicle to flatten some of the tall grass and attempted to find a shady spot from which to watch our trap. It was another long slow morning, but in the afternoon we finally got some activity.
My heart is racing as the first vultures finally start to land at our carcass. They have followed in a juvenile Bateleur eagle which landed and fed for a few minutes before being joined by the vultures. The vultures that have just landed are called Hooded Vultures because of the thin layer of feathers that grace the tops of their heads. I sometimes call them “Hoodies” since it looks like they are wearing feathered hoodie jackets.
At first it is just a single pair of adult vultures. They peer cautiously up into the sky, their blue eyes gleaming in the sun. Vultures are always on the lookout for future competition, of which there is much. A carcass is a coveted resource—bountiful food for whoever discovers it and, particularly, for whoever can defend it. As the smallest of the local vultures, the Hoodies won’t stand a chance against any of the other scavenging species, but still they watch for competitors, particularly for other Hooded Vultures. When a new pair of Hoodies finally discovers the carcass, they chase off the first pair. Flying at each other with talons reaching out, the two pairs grapple first on the ground, then in the trees, and finally in the air. Eventually the new, much-hungrier Hoodies are able to take over and push off the old pair.
With all the grappling, I’m hopeful that someone will snag a foot in one of our nooses. Though our movement study is currently focused on White-backed Vultures, a look into the lives of Hooded Vultures could be quite interesting as well. Little is known about these small vultures and where they go, breed, and feed, so it would be worthwhile to put a satellite tag on one if we caught it. As the afternoon goes on, nine Critically Endangered Hooded Vultures land at our little carcass, but not one slips a noose. We are left with some interesting behavioral observations, but no bird in hand.
February 15, 2016
We have been waiting for a few hours. The cool morning air has finally passed and thermals (warm swells of rising air currents) are starting to form. Vultures, particularly the larger ones like the White-backed Vultures we are trying to trap, rely on these thermals for soaring. Without the air to help lift them, they can’t fly very far. Now that it is nearly 11:00 AM, the vultures are in the air. At first we see a few at a distance, leaving their overnight roost for a day in search of carrion. Slowly we see a few pass over us. Surely they must have seen our bait, but they jsut pass by. Then the numbers start to grow and more and more are flying past, flying overhead, and circling nearby. We count the birds overhead and note the various species we see. Most of this morning’s birds are White-backed Vultures, but there are also a few of the smaller Hooded Vultures. If only they would land!
Then a single Hooded Vulture comes down to the carcass. The bird sits and looks at the swirling vultures above it before being to eat. Then a single White-backed Vulture lands and we begin inching the car forward, getting a little closer in preparation of a vulture tripping a noose. Suddenly an avalanche of vultures arrives. One after another they come zooming to the ground, so quickly that we lose count in the frenzy. The birds are feeding rapidly now and boisterously fighting with each other. We continue driving closer; it is only a matter of time before we catch one now.
Sure enough, something startles the birds and, as one tries to take off, it finds itself secured to the ground by our noose. Unsure what has happened, the other birds fly off. We drive in quickly and I hop out of the car, carrying gloves and a towel to defend myself against this ten-pound bird. The vulture turns towards me and hisses like a goose as I approach. I throw the towel over its head and, after a short dance with it hopping around beneath the towel, I lunge for it, grabbing one hand around the back of the head and the other around the wings.
Once the bird is secured, my team starts to move in as well—the “Tumbusi Trio” (Tumbusi means vulture in Kiswahili) has sprung into action. Claire from the Wildlife Conservation Society (WCS) is already helping me prepare the materials for attaching the telemetry unit. Liz from the Tanzanian Bird Atlas (TBA) moves forward to take the bird from me. As I step towards her, I realize that I too am caught in the noose, and that my foot is also attached to the carcass. Liz releases me before we pull the noose off the vulture, and then she secures her grip on its head. With that long neck, vultures are incredibly powerful and the beak is by far the most dangerous part of the bird. Unlike other raptors, vultures have dull talons, so the feet are really not a major concern.
We step into the shade and the real work begins. The goal is to attach the transmitter by creating a custom-fit backpack just for the bird, to take blood for sexing and other tests, to assess the age and condition of the bird, and to weigh the bird. Ideally this would take less than 30 minutes in order to minimize stress.
The vulture regurgitates a bit during the process. If attacked by a predator, this distraction may help the vulture escape (it also helps to lighten the load so that a full bird can take off quickly if it is being attacked). The bird struggles a few times and, after each round, we wait for it to calm down before continuing. This vulture is feisty and strong.
I set the transmitter on the bird’s back, with the solar panels facing up; with any luck these should keep the battery going for a year or more. Loops go from the bottom of the transmitter, pass between the legs and then over the shoulders before attaching to the top of the transmitter. Everything needs to be secure so that the unit doesn’t slip and the backpack doesn’t catch on anything, but not so tight as to harm the bird. Two clamps are fastened to the backpack, one above the tail and one along the belly to hold everything in place. I then tie and superglue a knot with the two straps to fasten the backpack onto the bird. I check carefully for fit before tightening the knot and cutting off the extra pieces of Teflon tape and aquarium hosing.
We open one of the bird’s wings to assess its age. We see the huge white band along the top half of the wing and determine that it is clearly an adult bird. I feel along the keel, which runs in the middle of the breast of the bird, and can tell the bird is healthy and in good condition. We then lift the vulture up so that I can take a small sample of blood from its foot. The vulture’s black feet hide the veins initially but, after I hold the leg to build up the pressure, the vein is visible. I put the needle between the black scales on the foot to take one cc of blood. Without a blood sample, we have no way to know the sex of the bird. In addition, the sample can also be used for DNA analysis and to test for lead exposure. Just like California condors, African vultures encounter lead when eating animals killed by hunters or poachers. We are just starting to assess the level of lead exposure and its effects on African vultures. In Tanzania, where hunting is legal and common and elephant poaching is on the rise, lead might be a serious problem for these scavengers. Blood in hand and transmitters sitting nicely on the bird’s back, it is time to release the vulture.
I take a video as the vulture, now with a satellite transmitter secured to its back, flies away. For the next year or more, I will know this bird only as a dot on a map, making its incredibly journey around Tanzania and potentially beyond its borders. I take one last look as the vulture hops, shakes itself, and takes off.
February 16, 2016
After yesterday’s success, the “Tumbusi Trio” (also known as the “Three Vulture Mamas”) are feeling good. Success should lead to more success. It means we have found an area frequented by the birds, where they are comfortable feeding and where we have good visibility to trap safely. Now all we have to do is do it all over again. We set our trap and position ourselves about 100 meters from the carcass, just like we did yesterday. The weather is fantastic. Despite what has already been an unusually wet rainy season, today is sunny and warm. This means that there should be plenty of thermals lifting the vultures from their overnight roosts and theoretically bringing them back to our carcass and nooses for another day.
Hours pass and we do see a few birds overhead, but it is nowhere near the level of activity that we saw yesterday. Where are all our vultures? Did they take advantage of the good weather yesterday and this morning to fly higher and travel farther away? Is there a poached elephant or other large carcass elsewhere in the area that they are all feeding on? We have no way of knowing (at least without more transmitters attached) what it is that the vultures are doing on a day like today. All we can do is wait.
By noon all of our optimism from the morning has passed. We are highly unlikely to catch any White-backed Vultures at this point in the day. By late morning most birds will have travelled to wherever they are going to search for food and will mostly likely be eating something else. At 2:00 PM, a few of the smaller Hooded Vultures have found our carcass and landed. They pick gently along the carcass—without the help of their larger relatives they will hardly make a dent in the carcass. A Hooded Vulture has a crop, a sack beneath its neck where it stores food, that can hold about a golf ball-sized amount of meat; the crop can hold about 200 grams (seven ounces) at most. A White-backed Vulture, on the other hand, has an enormous crop and can eat over two pounds in a single sitting at a carcass. With no competitors, the Hooded Vultures feed to their hearts’ content. By late afternoon we are forced to accept defeat and pick up our carcass and nooses and go back to camp otherwise empty-handed.
February 17, 2016
After yesterday’s failure, none of us are sure what to expect. Will we have more vultures fly over today? If they fly over, will they land? We set up our carcass; after two days in the sun it is quite rotten and smelly. The carcass is covered in maggots, which are the larvae of flies. If nothing comes soon to eat this dead animal, the flies will have won the competition and their population will grow as the maggots turn into adults. In a world with no vultures, flies and bacteria would likely become major players in the scavenging world and we could expect to see increases in their numbers, along with accompanying increases in disease. We really need vultures, as they can consume not just the carcass but any disease it is carrying and any maggots that may have infested the meat, to keep the environment safe and clean. Fingers crossed that vultures arrive today. Not only do we have one more satellite transmitter to attach, but I’d hate to see all these flies hatch and I am not looking forward to another day of handing our very rotten carcass.
With carcass and nooses set, we position ourselves a hundred meters from the trap. The early morning is slow as expected. There are just a few eagles and some migrating White Storks fly over, but we don’t see many vultures. By 10:00 AM I’m starting to get nervous. Perhaps the vultures don’t want to land at the same location where we trapped only a few days ago. Or maybe they are suspicious about seeing a new carcass in the same location. At 10:30 AM my concerns are relieved as the day’s first White-backed Vultures fly directly overhead.
Within 15 minutes birds are landing at the carcass. We hadn’t even seen them in the air beforehand, so it is as if they have appeared from nowhere, like magic. Vultures can see several kilometers away when they are in the air and, usually, they are also watching each other and waiting for someone to land. A landing vulture will be seen by others from kilometers away; those vultures will speed up to land as well, and then other vultures even farther away will see their behavior and follow suit. Once the first bird lands, over 20 vultures—mostly White-backed vultures, but also Hooded, Lappet-faced, and White-headed Vultures—land within the next few minutes. We even hear an incredible sound like a jet landing as one vulture tucks its wings in and rushes into the carcass at great speed, perhaps having travelled two or three kilometers (about two miles) in less than 2 minutes. As the fighting begins, we inch towards the carcass and, in less than 10 minutes, we have caught a beautiful White-backed Vulture.
Our second vulture couldn’t be more different from the first. As soon as I have it in hand, the bird is completely relaxed. Liz checks its breathing to make sure that it is alright, but I’ve seen this before. Some vultures just become calm, almost playing dead, once caught. This makes the process of attaching the transmitter a lot easier. As I fasten the straps over its shoulders, I’m impressed by the size of this beautiful bird. Its wingspan is over five feet (just under two meters) and is easily greater than my height. It also has an incredibly long body compared to our last vulture. While female vultures are generally slightly larger than males, the size difference is minimal and in this case may just be individual variation. Our first bird, though also an adult, just happened to be a lot smaller than our second. We take a little bit of blood from the bird and are ready to set it free. I set it down and it takes off immediately, running along and bursting into the sky. We watch the transmitter and can see it sitting securely on the vulture. I sigh in relief and elation.
This time there is a bit of meat left on the goat carcass, although in just ten minutes of feeding the vultures have done a lot of damage. We pull up the nooses and drive away to watch the remaining birds finish it off. Many have landed in trees nearby and watched as we handled their vulture friend.
As we drive off many of the birds re-land at the carcass, including the magnificent and massive Lappet-faced Vultures. These birds have heads so large that when I’ve handled them I had to hold them around the neck as their skulls were too wide for me to hold their heads. They are the ultimate strongmen of the vulture world; they are able to break a skull in half and bite ribs off a carcass one-by-one. The Lappet-faced Vulture and small group of White-backed Vultures make quick work of the remaining meat until just one young Hooded Vulture remains. It picks around the final scraps, reaching through the nostrils to grab pieces of brain and gleaning any remaining maggots from the bones. In less than an hour, there isn’t even enough meat remaining to feed a Hooded Vulture, and all the birds head off. At least for one of the departed, we will be following it and will soon know where it went after feeding at our carcass…thanks to its newly fitted satellite transmitter.