Tag Archives: woodpeckers

Woodpeckers show signs of possible brain damage, but that might not be a bad thing

(Field Museum, ScienceDaily 2 February 2018; Photo:Arlene Koziol)

With woodpeckers, the answer’s in the question—true to their name, they peck wood. And when they do, they peck hard—with each peck, the bird undergoes a force of 1,200 to 1,400 g’s. By comparison, a measly force of 60-100 g’s can give a human a concussion. The fact that a woodpecker can undergo fourteen times that without getting hurt has led helmet makers to model their designs around these birds’ skulls. However, a new study in PLOS ONE complicates this story by showing that woodpecker brains contain build-ups of a protein associated with brain damage in humans.

“There have been all kinds of safety and technological advances in sports equipment based on the anatomic adaptations and biophysics of the woodpecker assuming they king. The weird thing is, nobody’s ever looked at a woodpecker brain to see if there is any damage,” says Peter Cummings of the Boston University School of Medicine, one of the new study’s authors.

To find the answer to this question, researchers used bird brains from the collections of The Field Museum and the Harvard Museum of Natural History and examined them for accumulation of a specific protein, called tau.

“The basic cells of the brain are neurons, which are the cell bodies, and axons, which are like telephone lines that communicate between the neurons. The tau protein wraps around the telephone lines—it gives them protection and stability while still letting them remain flexible,” explains lead author George Farah, who worked on the study as a graduate student at the Boston University School of Medicine.

In moderation, tau proteins can be helpful in stabilizing brain cells, but too much tau build-up can disrupt communication from one neuron to another. “When the brain is damaged, tau collects and disrupts nerve function—cognitive, emotional, and motor function can be compromised,” says Cummings.

Since excessive tau can be a sign of brain damage in humans, Farah and his team decided to examine woodpecker brains for tau build-up. The Field Museum and Harvard loaned the researchers bird specimens pickled in alcohol—Downy Woodpeckers for the experimental data and non-head-injury-prone Red-winged Blackbirds as a control. The researchers then removed the birds’ brains—“The brains themselves were well-preserved, they had a texture almost like modeling clay,” says Farah—and took incredibly thin slices, less than a fifth the thickness of a sheet of paper. The slices of brain tissue were then stained with silver ions to highlight the tau proteins present.

The verdict: the woodpeckers’ brains had far more tau protein accumulation than the blackbirds’ brains. However, while excessive tau buildup can be a sign of brain damage in humans, the researchers note that this might not be the case for woodpeckers. “We can’t say that these woodpeckers definitely sustained brain injuries, but there is extra tau present in the woodpecker brains, which previous research has discovered is indicative of brain injury,” says Farah.

“The earliest woodpeckers date back 25 million years—these birds have been around for a long time,” says Cummings. “If pecking was going to cause brain injury, why would you still see this behavior? Why would evolutionary adaptations stop at the brain? There’s possibility that the tau in woodpeckers is a protective adaptation and maybe not pathological at all.”

So, woodpeckers show signs of what looks like brain damage in humans, but it might not be a bad thing. Either way, the researchers believe that the study’s results could help us humans. For example, the knowledge about woodpecker brains that could help make football equipment safer for kds, says Cummings. On the other hand, he notes, “If the tau accumulation is a protective adaptation, is there something we can pick out to help humans with neurodegenerative diseases? The door’s wide open to find out what’s going on and how we can apply this to humans.”

Farah notes that the study relied heavily upon the museum collections that the bird brains came from. “Museums are gateways to the past and a source of new innovation,” he says. “The role of museums in this project was immense—we couldn’t have done our study with just one woodpecker.”

Ben Marks, The Field Museum’s Collections Manager of Birds, said of the researchers’ request to use the Museum’s bird brains, “With one of the world’s best bird collections, we’re always trying to let people know what we have, why we have it, and what it can be used for. We get over a hundred requests for specimen loans every year—this one stood out because it was a novel approach that had real world applications. Some of the specimens used in this study were collected in the 1960s. Our staff cared for them for over 50 years before until they were requested for this study and used in a way the original collector couldn’t even envision.”

Solar tracking gives scientists tools to follow small animals

( 21 June 2017; Photo: Hana Londoño Oikawa)

Keeping tabs on wild birds has long been a low-tech proposition. While radio collars and satellite tags became standard for tracking big mammals, binoculars and notebooks have remained critical for following most twittering, flittering birds.

The holdup has been battery weight. To bleep the signals that reveal an animal’s location, transmitter tags require power. But for birds that weigh no more than a few pennies, even a watch battery can be too much to bear. Add in the need for recapture every few days to replace those batteries, and the dream of automated animal tracking becomes a logistical nightmare.

Now, new, lightweight tracking tags are making small animal tracking feasible. During field testing at the NRS’s Hastings Natural History Reservation, it’s given scientists a whole new perspective on the acorn woodpeckers (Melanerpes formicivorus) they’ve watched for decades. The birds turn out to be a lot more sly and strategic than researchers had long believed.

“You’d think that after almost 50 years of study, we’d know all there was to know about acorn woodpeckers. But this technology is helping us to answer questions we couldn’t answer before,” says Eric Walters, a biology professor at Old Dominion University, Virginia.

Woodpecker families are weird

These scarlet-capped birds are head-scratchers, all right. For starters, their family structure is among the most peculiar in the avian world. Several related birds of one sex (often sisters), typically breed with an unrelated set of several related birds of the opposite sex (often brothers).

Another puzzler surrounds the life choices of young woodpeckers. Where most fledglings leave the nest to found their own families, young “helper” woodies may linger at home for a decade.

“The question we had is, why? There must be some benefit to staying at home,” Walters says. “Do they spend their time at home helping to feed their siblings and store acorns? Or are they like teenagers in the basement watching TV all day and doing nothing?”

Game of Granaries

Walters suspected the answer lies in a young woodpecker’s thirst for territory. Like the fictional nobles in “Game of Thrones,” birds will do anything to conquer their own kingdom. Their goal is to secure a good granary tree, which houses the acorn stash critical to a woodpecker family’s survival.

A massive granary tree affords a woodpecker family plenty of advantages. They’re more likely to survive harsh winters, raise surviving chicks, and ensure the triumph of their own bloodlines.

Good granaries are tough to come by. It takes an age to build one — the hole for one acorn might take ten minutes to excavate, and large granaries may hold tens of thousands of acorns. Competition to secure the biggest granaries and their surrounding territory is fierce.

Gang wars

A granary goes up for grabs only after all breeders of one sex in a family group have died or left. When a breeding spot opens up, birds from other families battle over the succession.

Successful combatants don’t show up alone. Instead, groups of siblings from other territories duke it out.

“It’s like a gang war,” says graduate student Natasha Hagemeyer, who is studying woodpecker dispersal at Hastings with Walters.

Clashes may last for days, with foes hunting one another through the trees, grappling in midair, falling to the ground, and hammering one another with their powerful bills.

Grievous injuries aren’t uncommon. “One had a toenail torn out and bled profusely. Another got some of its wing feathers ripped away; it disappeared within a week,” Hagemeyer says. But the potential spoils — the chance to breed — are worth any cost.

Waiting in the wings

When a rare vacancy does open up, aspiring replacements are ready. “When we caught a breeding bird to band, other birds thinking it was gone would move in and start challenging for that territory within ten minutes,” Walters says.

How neighboring birds figured this out was a mystery. “We almost never see them off territory,” Hagemeyer says.

Previous studies done with radio transmitters indicated young birds do go on longer forays off their own family’s domain. “But when you radio track on foot with handheld antennas, you can only follow one bird at a time. To follow a set of siblings, you need a one-to-one ratio of people and birds. It rapidly becomes infeasible. And if an animal wants to be sneaky, like going into an enemy’s territory, you can spook them, making tracking just about impossible,” she says.

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