Pileated Woodpecker
Overhead songbird migration and captures have been slow at the Lesser Slave Lake Bird Observatory as the end of Fall Migration Monitoring nears, but that is not to say nothing interesting has happened. We caught a Pileated Woodpecker – only the thirteenth we have ever banded and the first since 2019! As Canada’s largest woodpecker, and with this bird clocking in at 368.8 g, these woodpeckers are too large to be effectively caught by our nets which typically max out at 90 g American Robins. In fact, he did partially collapse and escape a different net earlier that morning.
Like all woodpeckers, the Pileated claims its territory by drumming their bills against trees. They will also use their drilling skills to hunt insects in tree trunks, and to excavate nesting cavities in snags. These nests can take up to six weeks to complete and while Pileated Woodpeckers will rarely reuse them, other species like bats, owls, and ducks will take advantage of their hard work.
Repeatedly slamming their bill against wood is a tough physical undertaking, but woodpeckers are built for it. How exactly they avoid concussions and blacking out while drumming is still being studied, but characteristics such as body size, neck muscles, and the overall short duration of hammering likely help. Woodpeckers also have less brain fluid and a specific brain size and orientation to keep it from bouncing around the skull. Woodpeckers also have an extra long hyoid bone which can be found in humans necks between our chins and thyroid cartilage and supports our tongues. In woodpeckers, this bone starts at the nostrils and wraps over the top of the skull to end back near the beak. This allows them to have exceptionally long tongues that likewise wrap around their skulls and are thought to act like a seatbelt for their brains when pecking. Another hypothesis was that the spongy bone of the skull helped absorb impact. However, shock absorption would reduce the efficacy of hammering, dispersing the force so the bird would actually have to peck harder.
Among the latest woodpecker research is studying the tau protein which helps hold neurons together in our brains. Dislodged build up of tau proteins occurs naturally as we age, but this build up is also found in patients with diseases like Alzheimer’s, as well as those with concussions. At first, woodpeckers were assumed to avoid brain injury altogether, but a look into this tau protein build up in woodpecker brains suggests that is not entirely true. However, it is uncertain whether the build up is as detrimental to woodpeckers as it is to humans. Perhaps it is actually helping protect the woodpeckers’ brains from the force of their hammering, or there may be a mechanism that dissolves the build up that has yet to be explored.
Meanwhile our Owl Fall Migration Monitoring program has banded just over 50 Northern Saw-Whet Owls and two Boreal Owls already! Dishonourable capture mentions include a bat and a flying squirrel with a taste for nets. See our website for information on our upcoming Owl Nights in early October!
By Bronwyn Robinson, LSLBO Assistant Bander
References
- Biewener, A. A. (2022). Physiology: Woodpecker skulls are not shock absorbers. Current Biology, 32(14), R767–R769. https://doi.org/10.1016/j.cub.2022.06.037
- Savitsky, Z. (2022, July 14). Contrary to popular belief, woodpeckers don’t protect their brains when headbanging trees. Science. https://www.science.org/content/article/contrary-popular-belief-woodpeckers-don-t-protect-their-brains-when-headbanging-trees
- Langin, K. (2018, February 2). Could woodpeckers teach the NFL how to prevent brain injuries? Science. https://www.science.org/content/article/could-woodpeckers-teach-nfl-how-prevent-brain-injuries
- Farah, G., Siwek, D., & Cummings, P. (2018). Tau accumulations in the brains of woodpeckers. PLoS ONE, 13(2), e0191526. https://doi.org/10.1371/journal.pone.0191526
