Silent Savanna: Where are the Serengeti’s Wild Dogs?

African wild dog alert and lookingWhy did wild dogs vanish in Serengeti National Park? New answers are emerging. (Photograph: Per Harald Olsen)

It was the year when the Serengeti National Park’s music, or at least one section in its chorus-of-the-wild, died. In 1991, the twitters and whines of African wild dogs went strangely silent in Tanzania’s iconic protected area.

Scientists began tracking wild dogs, also called painted wolves, here in 1964. Over the next quarter-century, researchers watched as the wild dog population dwindled, then disappeared. Why did these canids effectively go extinct in a land where gazelles and other prey were plentiful?

Could the biologists themselves somehow be responsible?

African wild dog overlooking savanna.An African wild dog in Tanzania’s Ngorongoro Conservation Area surveys its domain. (Photograph: Per Harald Olsen)

The blame game

It’s anathema to researchers to think their actions might cause harm to an endangered species like the African wild dog. But in 1994, Roger Burrows of the University of Exeter unleashed the controversial idea that it was indeed scientists’ actions that led to the dogs’ demise.

Wild dogs became stressed, Burrows stated, when researchers immobilized and placed radio collars on them. The stress suppressed the wild dogs’ immune systems, he said, allowing diseases they already carried to kill them.

Burrows’ hypothesis rattled biologists who had long depended on radio collars to follow animals, especially endangered species. The implications went far beyond the Serengeti, say ecologists Craig Jackson of the Norwegian Institute for Nature Research, Eivin Roskaft of the Norwegian University of Science and Technology and colleagues at the Tanzania Wildlife Research Institute and Carnegie Institution for Science.

The team recently published a paper debunking Burrows’ thinking in the journal Ecology and Evolution. Serengeti wild dogs, the researchers found, weren’t the victims of science.

wild dogs runningWild dogs can roam onto Serengeti National Park lands. But they rarely do. (Photograph: Per Harald Olsen)

Life on the periphery

Although Serengeti National Park was, and is, without wild dogs, the dogs survived in the park’s outskirts. These outlier wild dogs have been studied since 2005. Many are outfitted with GPS collars; data show that the dogs sometimes briefly cross park boundaries. “Therefore, wild dogs could reside there,” says Roskaft. But they don’t.

There are now more than 100 wild dogs in 10 packs outside the park in the Ngorongoro Conservation Area and Loliondo Game Controlled Area. Between 2006 and 2016, Roskaft and colleagues report, 121 wild dogs from these locations were handled by researchers, with 45 of the dogs radio-collared.

How many of the 121 survived for a year or more afterward? Some 87.6 percent, or 106 wild dogs. Scientists’ “interventions did not evoke disease outbreaks, and the high survival rate does not support Burrows’ hypothesis,” the biologists write in their paper.

Ecologist Craig Packer, a National Geographic Explorer and director of the University of Minnesota Lion Research Center, has studied lions in the Serengeti for more than three decades. Packer, who was not involved in the study, agrees with its conclusions. “This paper,” he says, “nails the coffin on the whole debate.”

wild dogs at killWild dogs face competition from hyenas at kill sites. (Photograph: Per Harald Olsen)

In: Hyenas and lions. Out: Wild dogs. 

More than 25 years after wild dogs vanished from Serengeti National Park, none roam its grasslands. The answer, ecologists believe, is also the reason the dogs first faded away: hyenas and lions.

Rather than an extinction, Roskaft says, wild dogs’ disappearance was a shrinking of their range in response to increasing numbers of hyenas and lions. These carnivores often scare wild dogs away from their food.

The dogs moved out to the “far suburbs” — hillsides to the east of the park. The hills may offer safe places for wild dogs to den and raise their young.

With wild dogs out of the way, hyena and lion populations boomed. Any wild dogs brave enough to stay were left with slim pickings.

The evidence is clear, says Roskaft. “Increasing competition from hyenas and lions likely led to the downfall of the Serengeti National Park wild dog population.”

Packer and colleagues came to a similar conclusion. Between 1966 and 1998, the park’s lion population nearly tripled, they found, and wild dogs declined. Wild dogs once occupied park areas with low numbers of lions, which the dogs abandoned as lions “saturated” the region.

Serengeti prey animalsSerengeti National Park offers wild dogs – and other predators – plenty of prey. (Photograph: Per Harald Olsen)

A seesawing Serengeti

The picture was once very different. In the 1960s, Serengeti National Park was recovering from the effects of rinderpest, a disease of cattle that infected ungulates such as wildebeest and buffaloes – lions’ prey. The park’s lion population declined, and its wild dogs increased.

As rinderpest was brought under control and ungulates returned, lions followed. Soon wild dogs were edged out.

“A large number of wildebeest and lions, however, is a more ‘natural’ state for the Serengeti than the conditions that once allowed wild dogs to occupy its plains,” says Packer.

The big puzzle, he says, “is why wild dogs are able to co-exist with lions in places like the Selous Game Reserve in Tanzania and Okavango Delta in Botswana. We suspect there’s something about the habitat that provides the dogs with ‘safe spaces.’”

With more answers needed, Roskaft is happy to put an end to the conjectures about radio collars. “Tools that help us understand endangered wild dogs and other species are important to protecting these animals,” he says, “especially in a world where carnivores are struggling in the face of a growing human population.”

No wild dog twitters and whines wend across Serengeti National Park. But, says Packer, “effective conservation requires multiple locations since species cannot always co-exist in all circumstances.”

To wild dogs traversing the Serengeti: at least for now, your melody is perhaps better sung in the savanna next door.

wild dog lookingA wild dog in the Ngorongoro Conservation Area gazes across the savanna. (Photograph: Per Harald Olsen)

Wildlife

Africa, African wild dogs, conservation, Ecology, endangered species, environment, mammals, science, Serengeti, Tanzania

Seabird Riches on the Poor Knights Islands

In the far north of New Zealand lie the rugged Poor Knights Islands, off-limits to terrestrial tourism, but surrounded by a stunning marine reserve containing one of Jacques Cousteau’s top ten dive sites. Why are these prismatic waters so rich with life? One likely factor is the abundance of seabirds that breed here, bringing nutrients they’ve consumed at sea and depositing them on land—with a cascade of effects on the coastal ecosystem.

It’s a rare privilege to see the underwater world around this archipelago, but even luckier is being part of a research expedition with a special permit to go ashore. Along with the Northern New Zealand Seabird Trust and Radio New Zealand’s Alison Ballance, I caught a ride on a dive boat to one of the Poor Knights Islands to study its influential (yet elusive) seabird inhabitants.Aorangi Island (Illustration by Abby McBride)

Buller’s shearwaters or rako are slender seabirds that traverse the Pacific and can be seen off the California coast (where they’re sometimes called New Zealand shearwaters), but their only nesting place worldwide is right here. Aside from enriching the Poor Knights ecosystem with their guano, the birds have also used their clawed feet to engineer a unique landscape. The forest floor here is largely a forest crust, with a vast city of burrows beneath.

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Visiting the home of the shearwaters is a multi-sensory experience. You land in a dinghy on sharp volcanic rocks with a surge and a splash. You spend a couple of hours lugging loads of gear across the craggy shoreline, encircled by a 360-degree technicolor vista of towering cliffs and sun-filled waters. You climb into the shady forest and set up your tent, smack in the middle of a neighborhood of musky-scented nest burrows. (They seem to be deserted during the day, but you know better).

You spend mornings and afternoons struggling up and down steep forest slopes, tracking down audio recorders to switch out their batteries and SD cards—meanwhile walking above thousands of shearwater burrows and taking great pains not to break through their roofs. You lie face down in the leaf litter and reach your entire arm into many of those burrows, each time hoping to feel a spirited nip from the fluffy chick you’ll be measuring, rather than the reptilian bite of a lurking tuatara.

Aorangi Island (Illustration by Abby McBride)

But perhaps the most remarkable sensory dimension of a Poor Knights seabird expedition is the soundscape. When the sun goes down and darkness falls, the adult shearwaters fly in from the ocean, crashing through the canopy and landing with spectacular thumps on the forest floor. After scuttling to find their burrows and feed their chicks, they spend the rest of the night making a grand old racket of yelps and cackles all around your tent. Just before daybreak they climb up boulders and trees, launching themselves back through the trees and out to sea, leaving stillness behind—soon broken by the musical dawn chorus of bellbirds.

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If you’re wishing you could experience this for yourself, great news! Ballance has produced a transportive RNZ episode about our trip. Take a few moments to listen in (and don’t miss her written story, which includes some photos of the resident sketch biologist).

Originally posted 2018-04-16 13:43:32.

Finding the World’s Most Endangered Gull

When I set out to find a nesting colony of the most endangered gull in the world, I fully expected to fail. Not that it should be hard to find if you’re in the right place, and I was—the river-crossed interior of New Zealand’s South Island. The black-billed gull (which is not a seagull) nests mainly on gravel river islands in the far south, feeding on little critters in the rivers and nearby farm fields.

Still, I suspected I might not run into any black-billed gulls at all, because I’m a haphazard naturalist and my usual technique is to bumble along and see what I see. This time I bumbled my way to the unassuming town of Lumsden, where there was a camping area near the Oreti River. Thanks to a tip from nature filmmaker Bill Morris, I knew this was one of the rivers where black-bills had nested in previous years. He’d asked me to let him know if I found a colony, because he was keen to film one. I’d said I would, omitting my fairly confident prediction that it wasn’t going to happen.

The black-bill is the only gull in the world classified as Endangered on the IUCN Red List. Ten years ago the population was estimated at 90,000 adults, but it’s been dropping precipitously for decades. Some of the culprits are invasive predators, invasive weeds encroaching on nest habitat, invasive people driving cars through active colonies, and effects of ocean warming on the fish and marine invertebrates that black-bills eat in the nonbreeding season.

It was late afternoon on Christmas Day when I arrived at my Lumsden campsite to search for some of these beleaguered gulls. I had spent the previous night sleeping in my car on a mountain pass (ignoring the stares of several bemused sheep) and at that point I was pretty hungry and tired. But like a committed finder of endangered species, I walked straight over to the river, eyes on the alert for small, pale, long-billed gulls. I found a vast gravel expanse, completely devoid of birds.

Oreti River (by Abby McBride)
No gulls here


Any spark of optimism that I may have been indulging died away immediately. Fortunately, my hopes had been so low that I wasn’t very disappointed. I reverted to my usual abstracted state and started strolling down the river, with an eye out for anything that might come along. I strolled until I couldn’t stroll any farther, having reached a point where two streams converged from either side of me. I strolled back upstream until the gravel beach shrank to nothing and the river was flush with the wall of streamside shrubbery. Oh well, at least I’d tried, I thought. I was about one second away from heading back to the campsite to eat and sleep.

Then I saw something in the distance—upriver, near a distant highway bridge to the north. A handful of white birds flying around. They couldn’t be. I raised my binoculars. They were.

With visions of food and a nap slipping away, I scurried back to camp and got in my car, drove to the highway, and parked at the bridge. I saw no trace of the birds. Where did they go? Maybe they were following a school of fish down the river, I thought, ruing my ignorance about their feeding habits (ahem: haphazard naturalist). I started walking south along the river, with my hopes dying down again. But I rounded a bend and saw them: a dozen or so black-billed gulls wheeling around.

I would have been happy getting a glimpse of a single black-billed gull, and here was a great look at a whole bunch of them, alive with sound and motion. It was thrilling. Then, as I got closer, I noticed the ground beneath them. It was completely white with gulls. This was no mere feeding frenzy: I’d stumbled onto a breeding colony.

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There were hundreds and maybe thousands of birds on the ground. It was hard to tell how many because they were packed on a flat gravel island, raised above the stream level and shielded by some grasses. I was shocked to have actually found what I was looking for.

My Christmas dinner (pasta and leftover snacks) tasted particularly delicious that night. My sleeping bag was especially comfortable.

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The next morning Bill showed up and we spent a full day with the black-billed gulls. I sketched and he filmed, and later he cautiously sent his camera drone over the colony. “You can see tire tracks from cars driving through,” he said. “Wonder if they’ve been going through while the gulls are there—I wouldn’t be at all surprised if they had.”

After we’d spent hours moving slowly toward the edge of the colony, a guy with a fishing pole appeared and walked right through it, scattering gulls right and left. I half expected him to ask us what we were doing, and I half hoped he would. “Well, we’re observing the most endangered gull in the world; what are you doing?“ I wouldn’t have actually said that.

But really, I’m reasonably sure that the fisherman didn’t realize the impact of his actions. Would anyone treat this bird and its habitat differently if they knew it wasn’t just a seagull, but a unique and endangered species? I think many people would.

Abby McBride is a sketch biologist and Fulbright-National Geographic Fellow. She is currently sketching seabirds and writing stories about extraordinary efforts to save these threatened animals in New Zealand, the “seabird capital of the world.” Here are some ways to support seabird conservation.

Black-billed gulls (by Abby McBride)

Originally posted 2018-02-10 06:49:32.

Ghostbusting the “Extinct” New Zealand Storm Petrel

It’s well past midnight on Little Barrier Island, called Hauturu in Māori—”resting place of the wind.”

Six of us have been lying on our backs in the wet grass since nightfall, squinting through the spatter of raindrops on our faces. A giant inverted triangle of light looms above the forest clearing, blurred by mist and striated with rain, shooting upward from a floodlight on the ground. Swirling in and out of the beam are the pale underbellies of hundreds of seabirds, their raspy laughter filling the air. They look like constellations of stars that have come loose and started careening around the sky.

Each time one of these rogue stars dips low enough, it comes into focus as a Cook’s petrel, the most abundant bird breeding on this island. But we’re looking for a star that becomes another kind of seabird: a storm petrel.

The New Zealand storm petrel, thought to be extinct for the entire 20th century, was recently found nesting here—a forest-covered old volcano in the Hauraki Gulf, lying a scant fifty miles north of the city of Auckland. It has no other known breeding sites in the world. Its call is loud in our ears, coming from a speaker placed on the ground to draw the birds toward us. Actually, this is the only audio recording of this species in existence: a plaintive note alternating with a sort of squawk, looping every fifteen seconds. We’ve been hearing it on repeat for hours, and I’m fighting a losing battle not to memorize it.

Rain is slowly soaking into my supposedly rainproof jacket and pants, and moisture from the waterlogged ground is seeping in from below. My socks and boots are sopping wet, a delightful reminder of the knee-deep puddle we had to walk through on the way here. Suddenly someone yells out. “Stormy!

Catching a New Zealand storm petrel (by Abby McBride)Capturing a New Zealand storm petrel on Little Barrier Island (Illustration: Abby McBride)

It’s scientist Matt Rayner of the Auckland Museum, and he’s not talking about the weather. We all jump up. Three high-lumen torches switch on and converge on an erratically moving shape, pale like the petrels but smaller and scrappier. It appears headless, its dark face disappearing against the sky while its belly reflects white.

Rayner and the other two torch bearers take off at a run, stumbling in gumboots through the hummocky grass, striving valiantly to keep their eyes and their lights on the target as it ricochets around the sky. Like some sort of backcountry ghostbusting team they’re maneuvering to form a triangle around the bird, which seems caught in the nexus of the three beams. Slowly, inexorably, the storm petrel is drawn in a swooping descent to the ground. Rayner gently picks it up.

It was 2003 when a bird that looked a lot like an extinct New Zealand storm petrel was spotted in the Hauraki Gulf, 108 years after its extinction date. Within the next few years, as sightings began to accumulate, scientists managed to capture some of the diminutive black-and-white storm petrels at sea. They confirmed the birds‘ identity genetically using the only three museum specimens in existence, collected in the nineteenth century. Finding this species still clinging to life was nothing short of miraculous. But to safeguard its recovery, researchers needed to know where the burrow-nesting bird was breeding. At that point nobody could be sure if the New Zealand storm petrel’s breeding site was in New Zealand at all.

Steffi Ismar with New Zealand Storm Petrel (by Abby McBride)Steffi Ismar measures the bill of a storm petrel

Rayner is now wading through the soggy grass, storm petrel safely in tow. He crawls under a tarp strung between two trees for shelter from the rain. Settling in next to a box full of banding and measuring tools, he checks the bird for a brood patch. Sure enough, its belly has a patch with no feathers, which means the bird is in active breeding mode. “This measurement was critical for us back in 2013,” he says.

That was when he and fellow researchers, searching for the storm petrel’s breeding grounds, first managed to catch some birds whose bare bellies meant they had nests nearby. In an epic tale of ingenuity and perseverance (recounted here by researcher Chris Gaskin), Rayner and colleagues traced the breeding storm petrels to Little Barrier Island.

Little Barrier is special: arguably New Zealand’s most intact ecosystem, it’s full to the brim with endangered plants and animals, some of which are found nowhere else. On this evening’s walk to the catching site we passed a giant weta sitting at eye level on a tree trunk, looking actually rather cute for a cricketlike insect the size of your hand. Geckos peek from the shrubbery on the edge of the clearing, and we’re hearing strident kiwi calls from the bush on both sides of us (not to mention the incessant “more-pork, more-pork” croaking of New Zealand’s only surviving native owl, which is called—wait for it—a morepork).

The key to this mini paradise? Predator control. Cats were eradicated from Little Barrier by 1980 and rats in 2004. Now the island is mammal-free, like it used to be in the not-so-old days before humans arrived with human-transported pests. In a part of the world where the wildlife evolved without land mammals for 80 million years, invasive predators are serious business—and controlling them can save multiple species of concern at the same time. This storm petrel we’re holding right now demonstrates another benefit of pest control: it can even save species you haven’t discovered yet. Rayner says it’s likely that the New Zealand storm petrel would have gone extinct for real, if Little Barrier hadn’t been cleared of mammals when it was.

Little Barrier Island, Hauraki Gulf, New Zealand

Now the cats and rats are gone, and the storm petrels are found—nearly 500 individuals captured and banded since their rediscovery, and a grand total of four nests located on Little Barrier’s steep slopes. But the work of saving this species isn’t over, which is why we’re here getting soaked. Banding and measuring and collecting blood samples are all part of understanding breeding biology, and that’s a crucial prerequisite to effective conservation.

One of the next big challenges for Rayner’s team is convincing some of the birds to take up residence in a colony of nest boxes—built nearby in the forest—because their natural burrows have proven too cryptic, inaccessible, and fragile to monitor. Another is to find out if there any other islands in the Gulf harboring the elusive storm petrels. The project chugs onward, in true New Zealand style, “on the smell of an oily rag,” with the small but mighty Northern New Zealand Seabird Trust carrying on a continual hunt for funding. Did I mention the floodlight we’re using is made out of aluminum foil, duct tape, tin scraps, and the remnants of an old catapult originally built for one of the island caretaker’s children?

We had a rough boat ride from the mainland to the island earlier in the day. We’ll be out in the rain until the wee hours of the morning and we’ll be back every night for ten days straight, catching and releasing bird after bird. Our gear will get wetter and the puddles will get deeper. But for this bunch, that’s all worth it—because seabird conservation in New Zealand gets results. One of them is this little storm petrel with a new band on its leg.

Read more about the rediscovery of the New Zealand storm petrel and learn how to support conservation efforts for this species.

Measuring and banding a New Zealand storm petrel (by Abby McBride)

Originally posted 2018-03-12 05:22:44.

Quick Stop at the Petrel Station

I drove through Punakaiki recently.

Once a year this west coast town holds a festival to welcome the Westland petrel back home to New Zealand after its annual sojourn to South American waters. Amid a weekend of music and revelry, festival-goers gather on the beach at sunset to watch thousands of large black seabirds assemble in the sky above the coast. The birds then fly en masse overhead toward the forest hills, as they do every night during their breeding season.

Punakaiki has good reason to be proud of these beautiful petrels, also known as a tāikos, because they’re truly a local specialty. All 4,000 or so pairs nest along this small patch of coastline. Unlike nearly all other burrowing seabird species in New Zealand, Westland petrels somehow avoided being pushed off the mainland when invasive mammals hitched a ride with humans to this part of the world (though the birds certainly struggle with predation on land, as well as with threats at sea).

I missed the Tāiko Festival by a few weeks, but I got to see something even better when I stopped through town. With the help of a conservation-minded landowner whose property holds dozens of nests, I visited the Westland petrel colony itself.

Westland sunset by Abby McBride

It was sunset when I parked in the driveway and followed Bruce Stuart-Menteath into the inland forest. In the gathering dusk we ascending long sets of wooden stairs that he’d built years ago to give petrel colony tours to interested parties. At one point, Bruce paused to explain something and was interrupted by a crash in the thicket off to the left. “That was a petrel,” he remarked, as we continued our climb.

At the top we sat down, and there the spectacle began in earnest.

Big dark birds were crash-landing in the forest all around us and shuffling along the ground to their burrows. Watching the dimly lit sky through a gap in the trees and ferns, we could see their silhouettes circling as they prepared for entry. One came straight at me: imagine looking at a Batman symbol (except more seabird-shaped) that gets larger and larger and then veers aside at the last instant to tumble dramatically onto the ground. I felt a whoosh of air, a brush of wings, and fortunately no puncture from that fearsome ivory beak.

After one of these landings, Bruce turned on a dim light so we could get a look at a petrel as it rested from the exertion. I had half a minute to sketch this one before it crept away toward its burrow.

Westland petrel by Abby McBride

Later on, another bird climbed up a stump in front of us—a customary launch pad, Bruce informed me—and spent about ten minutes contemplating an early departure back to sea. Several times it opened its long wings and flapped vigorously. But it ended up dropping back to the ground and meandering off into the bush. Apparently it would wait until the morning rush, when most of the petrels head back to the ocean under cover of darkness (to avoid the falcon, Bruce said).

We didn’t want to use too much light and disturb the petrels. But there was plenty to listen to, between the crashes and the rustlings and all manner of vocal performances, as the birds sat in their burrow entrances and loudly laid claim to their territory. Within a week or so they’d be laying eggs.

When we descended back to sea level that night, I accepted a kind offer for “tea and pudding” (that’s dinner and dessert in New Zealand) with Bruce and his partner Denise Howard. Then I camped nearby on the coast.

I emerged from my tent an hour before dawn and drove until I reached a stretch of road that Bruce had described to me. I got out of the car. Standing there with the world gradually lightening around me, I watched Westland petrels materialize in the distance above the hills and fly toward me in a wide, continuous stream. They flew over my head and past the moon with faintly swishing wingbeats, off for a day of feeding at sea.

The flood slowed to a trickle, and at last the final petrel flew over. The sun rose. I got back in the car and drove on.

Originally posted 2018-05-20 04:51:12.

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