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Sarah Knutie, University of Utah
Sarah Knutie, University of Utah

Galapagos Birds Beat Bloodsuckers with Pesticide-Lined Homes

Sarah Knutie, University of Utah
Sarah Knutie, University of Utah

In the 1990s, the fly Philornis downsi was accidentally introduced to the Galapagos Islands, probably in a shipment of fruit. The adult flies are harmless enough as invaders go, but their kids are a real problem for the islands’ native birds, some of which are found nowhere else in the world and a few of which are endangered.

The flies lay their eggs in birds’ nests just as the chicks are emerging from their own eggs, and once the larvae hatch, they begin to eat their hosts from both inside and out. No larger than grains of rice, the maggots wriggle their way into the baby birds’ nostrils and eat away at their nasal cavities. As they get larger, the parasites burst back out and continue to live in the nest, hiding by day and emerging each night to suck blood from the chicks. This is often too much for the birds to bear. In some years, the parasites have killed every single chick in a given area and caused every nest to fail. Even if the birds survive, they often have difficulty eating because their beaks are deformed from the larvae that crawled around inside.

Among the birds that the flies maim and kill are Darwin’s finches, a group of 15 related species whose beaks diverged in form as adaptations to their function and were a key piece of evidence for Charles Darwin when he was developing his idea of evolution by natural selection. And even though they’re textbook examples of adaptation, the birds haven’t adapted to the parasites yet because they don’t have a long evolutionary history with them. For now, it falls to scientists to protect them. Conservation biologists have tried treating the nests with insecticides, which increases the number of chicks that survive long enough to fly on their own, and also removing chicks of the most vulnerable species from their nests and raising them in incubators.

Neither of these strategies is inexpensive or easy. Treating the nests is particularly tricky because they’re often hard to find or placed too high in the trees to reach. Now a team of biologists thinks they’ve found a new, more efficient way to do it: lend the birds the insecticides and let them be their own exterminators.

The idea came to University of Utah doctoral student Sarah Knutie as she watched finches come to the laundry lines outside her island dorm and pull threads from clothes and towels to add to their nests. She wondered if the birds would also take fibers that had been treated with permethrin—an insecticide often used in flea collars and lice shampoos—and work them into the nests to “self-fumigate” them.

To find out, Knutie, other students and their advisor Dale Clayton fashioned 30 dispensers out of wire mesh, filled them with either permethrin- or water-soaked cotton, and placed them along a road near nesting sites on Santa Cruz Island.

When the breeding season was over and the baby birds left home, the researchers collected and dissected 26 empty nests built by four different finch species. Twenty-two of the nests contained cotton from the dispensers, and more than half of those contained the insecticide-laced cotton.

The birds were apparently happy to take the dosed cotton, and it paid off for them. The nests with the permethrin cotton in them contained about half as many parasites as the ones that had plain cotton or no cotton at all, and all but one of the nests with a least of a gram of treated cotton—about a thimble's worth—were parasite-free. 

If more cotton dispensers can be installed and maintained, they could make a huge difference for some of the islands’ birds. One of Darwin’s finches, the mangrove finch, has a population of less than 100 birds confined to about a square kilometer of land. It would only take 60 dispensers, Knutie says, to protect the whole population from the flies.

The researchers hope that the same method could be used to protect other birds and nest-building animals against parasites and pests, from Hawaiian honeycreepers dealing with feather lice to prairie dogs that are literally plagued by Yersinia pestis-carrying fleas. Just a little puff of cotton could go a long way in helping these animals help themselves. 

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Animals
Pigeons Are Secretly Brilliant Birds That Understand Space and Time, Study Finds
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Of all the birds in the world, the pigeon draws the most ire. Despite their reputation as brainless “rats with wings,” though, they’re actually pretty brilliant (and beautiful) animals. A new study adds more evidence that the family of birds known as pigeons are some of the smartest birds around, as Quartz alerts us.

In addition to being able to distinguish English vocabulary from nonsense words, spot cancer, and tell a Monet from a Picasso, pigeons can understand abstract concepts like space and time, according to the new study published in Current Biology. Their brains just do it in a slightly different way than humans’ do.

Researchers at the University of Iowa set up an experiment where they showed pigeons a computer screen featuring a static horizontal line. The birds were supposed to evaluate the length of the line (either 6 centimeters or 24 centimeters) or the amount of time they saw it (either 2 or 8 seconds). The birds perceived "the longer lines to have longer duration, and lines longer in duration to also be longer in length," according to a press release. This suggests that the concepts are processed in the same region of the brain—as they are in the brains of humans and other primates.

But that abstract thinking doesn’t occur in the same way in bird brains as it does in ours. In humans, perceiving space and time is linked to a region of the brain called the parietal cortex, which the pigeon brains lack entirely. So their brains have to have some other way of processing the concepts.

The study didn’t determine how, exactly, pigeons achieve this cognitive feat, but it’s clear that some other aspect of the central nervous system must be controlling it. That also opens up the possibility that other non-mammal animals can perceive space and time, too, expanding how we think of other animals’ cognitive capabilities.

[h/t Quartz]

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The Queen's Racing Pigeons Are in Danger, Due to an Increase in Peregrine Falcons
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Queen Elizabeth is famous for her love of corgis and horses, but her pet pigeons don't get as much press. The monarch owns nearly 200 racing pigeons, which she houses in a luxury loft at her country estate, Sandringham House, in Norfolk, England. But thanks to a recent boom in the region’s peregrine falcon population, the Queen’s swift birds may no longer be able to safely soar around the countryside, according to The Telegraph.

Once endangered, recent conservation efforts have boosted the peregrine falcon’s numbers. In certain parts of England, like Norfolk and the city of Salisbury in Wiltshire, the creatures can even find shelter inside boxes installed at local churches and cathedrals, which are designed to protect potential eggs.

There’s just one problem: Peregrine falcons are birds of prey, and local pigeon racers claim these nesting nooks are located along racing routes. Due to this unfortunate coincidence, some pigeons are failing to return to their owners.

Pigeon racing enthusiasts are upset, but Richard Salt of Salisbury Cathedral says it's simply a case of nature taking its course. "It's all just part of the natural process,” Salt told The Telegraph. "The peregrines came here on their own account—we didn't put a sign out saying 'room for peregrines to let.' Obviously we feel quite sorry for the pigeons, but the peregrines would be there anyway."

In the meantime, the Queen might want to keep a close eye on her birds (or hire someone who will), or consider taking advantage of Sandringham House's vast open spaces for a little indoor fly-time.

[h/t The Telegraph]

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