Eyes in the sky: How ground-bound mammals use vultures to find a free lunch
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Eyes in the sky: How ground-bound mammals use vultures to find a free lunch

Posted on 03/15/17

ASHEBORO, N.C. –

  • On the plains of Africa, jackals and hyenas follow scavenging vultures to an easy meal
  • Declines in vultures may therefore have cascading effects on mammalian scavengers

Let someone else do it! That’s the attitude taken by hungry hyenas and jackals on the plains of Kenya in their search for food. Rather than finding a meal by themselves, they often look to the skies in order to spy on the movements of vultures.

When large groups of these iconic birds descend, they present an obvious signal to a carcass, which the mammals cue to. They are, in effect, the eyes in the sky for the mammals. This is a shrewd behavior because the view of animals stuck on the ground is often blocked by the lie of the land.

New work from biologists at North Carolina Zoo and University College Cork published in Journal of Animal Ecology used a combination of fieldwork and computer modeling to show that by using vultures, hyenas and jackals could find carcasses nearly twice as fast as if they had to search without them.

One of the authors, Dr. Adam Kane of University College Cork, previously showed that vultures themselves often scrounge on the discoveries of eagles.

Co-author Corinne Kendall, who conducted the fieldwork in the Masai Mara National Reserve, said: “Curiously, the mammals never directly followed scavenging eagles. Eagles have a broad diet and also eat small prey, like snakes and mice, and thus they may not be a reliable signal when searching for larger carrion that mammals are actually looking for.”

Dr. Kane said: “What we’re seeing is a chain of arrivals at a carcass where the species that arrive early on tend to be the best spotters, whereas those that arrive later tend to be the most physically dominant. This is important because it means the first-comers must eat quickly before they are bullied off their dinner.”

“Although both jackals and hyenas are capable hunters, a carcass doesn’t fight back, so the mammals don’t have to work as much as they would for a hunt. They have an army of vultures to contend with but a vulture is quite a bit smaller than your average hyena. The birds can’t afford injuries if they are to ever fly again, and so tend to concede their meals to the larger competitors.” 

By building computer models that used real-life animal data, the authors were able to predict the time that mammals should arrive at a carcass if they were cuing to the arrival of the birds.

Dr. Kane added: “We know how far a hyena can see and how fast it can move so it’s simple math to determine when it should appear at the carcass if it is indeed following the descending vultures.” 

Unfortunately, all African vulture species are on the edge of extinction. The results from this study suggest that as vultures disappear from the environment there could be negative impacts on the mammals who need a cue from above to find carrion.

Additionally, vultures provide an important ecological service in keeping diseases outbreaks down, so their dwindling numbers may coincide with unwelcome spikes of diseases like rabies, which can proliferate on rotting carcasses and be spread rapidly by animals eating the older, rotten meat.

That’s why North Carolina Zoo, in partnership with the Wildlife Conservation Society, has an on-going program to save vultures in Tanzania.

Media Contact

Adam Kane, [email protected] Irish Research Council funded researcher at UCC

Corinne J. Kendall, [email protected], Associate Curator of Conservation and Research at

North Carolina Zoo

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Find yourself surrounded by some of Africa’s giants including elephants, rhinos, and giraffes; share the love of gorillas with Mosuba and his six-member troop; polar bears Nikita and Anana take polar plunges every day at the Rocky Coast Exhibit; or join in the fun at the mud café in the Kidzone.

Located in the center of the state in Asheboro, it is convenient to visit from anywhere in North Carolina. The North Carolina Zoo welcomes nearly 800,000 guests each year. Plan your adventure at www.nczoo.org.

 

About the North Carolina Department of Natural and Cultural Resources 

The North Carolina Zoo is an agency of the N.C. Department of Natural and Cultural Resources. The N.C. Department of Natural and Cultural Resources (NCDNCR) is the state agency with a vision to be the leader in using the state’s natural and cultural resources to build the social, cultural, educational and economic future of North Carolina. NCDNCR's mission is to improve the quality of life in our state by creating opportunities to experience excellence in the arts, history, libraries and nature in North Carolina by stimulating learning, inspiring creativity, preserving the state’s history, conserving the state’s natural heritage, encouraging recreation and cultural tourism, and promoting economic development.

NCDNCR includes 27 historic sites, seven history museums, two art museums, two science museums, three aquariums and Jennette’s Pier, 39 state parks and recreation areas, the N.C.  Zoo, the nation's first state-supported Symphony Orchestra, the State Library, the State Archives, the N.C. Arts Council, State Preservation Office and the Office of State Archaeology, along with the Division of Land and Water Stewardship. For more information, please call (919) 807-7300 or visit www.ncdcr.gov.

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