Ahem. Anyway! Moving on.
In my last post, I listed a bunch of topics I’d talk about in future posts that I thought would interest people. Today, I thought I’d give a little information about the raptor species I’m working with: the gyrfalcon. I think this background information is awesome, but there are always those who might find it a little dry. If you fall into that category, read the following in the voice of either Morgan Freeman or David Attenborough. That’ll fix you right up.
Gyrfalcons are the largest species of falcon on the planet, and as far as I’m aware their top speed is second only to the peregrine falcon. They live all around the world in every arctic region, including North America, Greenland, Europe, and Russia. Like all raptors, the gyrfalcon exhibits reverse sexual dimorphism – meaning that the female is bigger and more dangerous than the male. This is because 1) the female is the one often defending the nest and 2) because it allows a pair of raptors to pursue small and fast prey (caught by the male) in addition to slow and large prey (caught by the female). Trust me, you don’t want to get on the bad side of a female bird of prey. In the raptor world, they mostly call the shots.
The gyrfalcon was the favored bird for training by medieval falconers (more on falconry at a later date), who considered the bird to be reserved for use by royalty. Due to that legacy, the gyrfalcon is the most prized species of raptor on earth by falconers. Some who train gyrfalcons might even keep their birds secret out of fear that another person will steal the raptor.
It’s because of that value that I’ve been asked to sign a confidentiality agreement with my host organization and the state of Alaska. While the gyrfalcon is a bird of least concern with the IUCN – meaning it’s doing just fine in the wild, thank you very much – high international demand for and low supply of live birds could collapse the wild population very quickly if given the chance. To make sure that falconers don’t accidentally push a species they love to extinction, raptor biologists carefully safeguard gyrfalcon nesting locations. It also helps that the birds tend to move nests from year to year and blend into the cliffs, making them difficult to find for even the most determined poacher.
Gyrfalcons are also fascinating raptors in that they appear linked to a particular type of prey. While it is true that peregrine falcons prefer to eat pigeons and osprey depend on fish, the gyrfalcon is a little different: it appears to have structured its entire breeding season around its ability to catch ptarmigan (a grouse, or a bird that spends a lot of its time on the ground). This is a significant part of the reason why I am performing research in Alaska, as the deep connection from gyrfalcon to ptarmigan greatly simplifies the system that I’m attempting to study.
“Cool!” you gush, awestruck by such an amazing bird. “I know arctic populations are supposed to cycle from year to year, so there would be lots of ptarmigan one year and much fewer then next. Does the gyrfalcon move from year to year following places where there are lots of ptarmigan?” Wow, great question, reader! We have no idea! Normally, solving questions like that requires us to place tracking devices on raptors that can send us constant data. However, there are no cell towers nearby for a GPS to piggyback onto, subzero winter temperatures quickly drain battery life, and there’s no sunlight in an arctic winter (so solar power is out, too). That leaves only raptor backpacks that can transmit via satellite, and for some reason every gyrfalcon that has been given one has died the following year (unusual, as raptor species normally do fine with them). No one knows why, although one of the field researchers here with me theorized that the problem comes from the backpack pressing down on the falcon’s back feathers. In theory, that would squash the thermal layer that the feathers were supposed to create to keep the bird insulated from the cold, causing the falcon to freeze in the winter. Plausible, but unproven.
I’ve probably rambled on long enough, that’s enough information for now. Next time, we talk about predation!