Hornbills in the Kalahari desert may keep cool by losing heat through their beaks

May 18, 2016

When temperatures are scorching, southern yellow-billed hornbills in the Kalahari Desert of southern Africa dilate blood vessels in their beaks to thermoregulate and cool off, according to a study published May 18, 2016 in the open-access journal PLOS ONE by Tanja van de Ven from the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa, and colleagues.

While mammals have sweat glands to keep their bodies from overheating, birds may rely on panting (evaporative heat loss) and dilating their blood vessels (non-evaporative heat loss), particularly in their beaks. Toco Toucans are an example of the latter: their outsized beaks account for up to 60% of their non-evaporative heat loss at air temperatures above 28 degrees Celsius. Although not as extreme as toucan beaks, hornbill beaks are still quite large relative to their bodies. To determine whether hornbills might likewise use their beaks for this purpose, the authors of this study raised the air temperature around 18 wild-caught southern yellow-billed hornbills and tracked their heat loss with thermal imaging.

The researchers found that the beaks accounted for up to 20% of the birds' non-evaporative heat loss, and suggest that the benefits of heat loss from beaks on hot days likely varies according to where the birds live. In tropical forests where toucans typically live, for example, beak heat loss could be key, as humidity may make panting less effective. For those southern yellow-billed hornbills living in the desert, beak heat loss could be important as, in contrast to panting, it may help to conserve scarce water.

Tanja van de Ven notes: "We have found that, like toucans, hornbills can use their beak as a controllable thermal radiator. We think this might provide an advantage in the arid Kalahari by reducing the amount of water the birds need to spend on evaporative cooling".

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Burnt out birds suggest hard work could be bad for your health

Date:

September 2, 2014

Source:

British Ecological Society (BES)

Unequal sharing of workloads in societies could leave the most industrious individuals at higher risk of poor health and prone to accelerated aging, according to a new study of a cooperative bird in the Kalahari Desert.

A team of scientists at the University of Exeter studied white-browed sparrow weavers, a social species in which all group members share offspring care duties, but the dominant male and female work hardest.

Dominants are the only birds that breed, with dominant males singing to attract a mate and dominant females producing all of the eggs and providing most of the care for nestlings. Both dominants also invest most in fiercely defending the group's territory.

Continued ...

Sly Birds Cleverly 'Cry Wolf' to Steal Food

By Stephanie Pappas, Senior Writer | May 01, 2014 02:00pm ET

The red-eyed, black-feathered fork-tailed drongo is an irrepressible mimic, capable of reproducing the calls of everything from other birds to mongoose-like meerkats. Now, a new study finds that these drongo birds are strategic copycats: They "cry wolf" about potential danger, startling other animals and stealing their food.

What's more, drongos (Dicrurus adsimilis) alter their cries to keep their targets from becoming inured to the trick.

This ability to change up calls when one of the calls isn't working may be an evolutionary way to get around the problem the little boy in Aesop's fable ran into: If you raise the alarm about danger too many times, eventually, no one listens. The problem plagues any animal that uses a deceptive strategy, said study researcher Tom Flower, a behavioral ecologist at the Percy FitzPatrick Institute of African Ornithology.

Continued

World's Largest Bird Nests: Photographer Dillon Marsh Snaps Social Weaver Homes In South Africa (PHOTOS)

Dillon Marsh, from Cape Town, spent three days wandering in the Kalahari Desert near the South African town of Upington to photograph the huge, avian-built homes. According to a photo caption provided to The Huffington Post by British photographic press agency Rex Features, the pictures were taken earlier in February.

"I had seen these nests as a child while on a holiday with my family and their impressive size had mesmerized me," Marsh told the Daily Mirror."I had started to develop an interest in the relationship between people and the environment, and these nests struck me as the perfect subject matter."

According to earlier research, the nests of social weaver birds (also known as sociable weavers) are believed to be the largest birds' nests in the world. Reminiscent of giant haystacks, each nest -- some of which can grow to over 20 feet wide and about 10 feet tall -- can be occupied by hundreds of sociable weavers at a time.

The San Diego Zoo, which houses a number of social weaver birds, said on its website that the massive nests, made up of twigs, grass, cotton and other natural materials, have to be constantly maintained by the birds.

The animals do this job diligently, however, and some nests have been known to last for about 100 years.

Other than providing a hiding place from predators, the nests are also said to be climate-controlled -- perfect for protecting the birds from the Kalahari Desert's harsh climate, the website of the World Association of Zoos and Aquariums explains.

According to a blog post on Scientific American, the apartment building-style nests are also perfect for social weaver birds, which raise their young communally.



Slideshow of more giant nests at: http://www.huffingtonpost.com/2013/02/25/worlds-largest-bird-nests-dillon-marsh-social-weaver-south-africa_n_2760633.html