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How to capture a Peregrine Falcon

Bridger, Jeff, and I just got back last night from almost a week camping out in Booth sound.  I’ll get to that excursion a little later, but first let me continue what I started about the peregrine and gyrfalcons.

This group’s mission when it first started coming to Greenland in the 70′s was focused solely on the Peregrine and Gyrfalcon populations. The group was actually under a completely different name, the Peregrine Fund, and was headed by Dr. Kurt Burnham’s father.  In more recent years, the Peregrine Fund no longer does work in Greenland, so Kurt created the High Arctic Institute to continue research here and to expand the focus from falcons to just about any bird that breeds up here.  The group still continues to do a lot of work with the peregrines and gyrfalcons, and so here is a little summary of what we’ve done so far.

At this time of year, the successful Peregrine pairs are sitting on nests.  So our first strategy is to find the Peregrine nests, called eyries.  The peregrines (and gyrfalcons alike) nest on ledges of tall cliffs, which are generally found on the coast line.  So we can either boat up to the locations and look for the nests from below, sometimes if we don’t see them, Kurt will fire a shot from the rifle to try and scare them up.  Or we can look for them from above, like I had with Bridger earlier on North Mountain and at BMEWS. After finding a peregrine on a nest, our goal is to catch her so we can put a geolocator on her.

Catching her is quite a feat, and each time it is a little different. Each time, once we’ve located the nest, we’ll set up a trap in the nest.  To do this, Bridger will repel down to the nest and set up nooses around the eggs.  We replace the eggs with some fake ones to make sure that they don’t get broken in the process.  After setting up the trap we sit and wait for the peregrine to come back to her nest.  Each bird acts a little differently depending on the weather the strength of her maternal instinct over the threat of humans. At BMEWS the peregrine was very wary of us and and reluctant to get back on her nest, while on Mt. Dundas, the peregrine was just about trying to get back into her nest while Bridger was in there setting up the nooses. Therefore, at BMEWS, everyone watching the nest had to cover up in camoflouge and sit very still, which is quite a challenge considering how many mosquitoes were there, and Dr. Burnham and I walked away from the nest to make it look like the threat had left. At Dundas however, Bridger was able to leave everything out in the open and sit right above the nest, while I sat across from the nest to let them know when the female had settle on her eggs. Once the peregrine settles in her nest, we scare her up, hoping that she will have slipped her talons into the noose.

Ironically, while the peregrine at BMEWS took a bit more patience for her to get back on her nest, she was a much easier catch; she got both her legs caught in the trap on the second try.  The peregrine on Dundas however was another story.  After she would settle, we would scare her up by shaking the rope. After a few tries she got stuck by only by the tip of her talon, and by the time Bridger was down into her nest to unhook her she had wiggled free. Pretty frustrating. Nevertheless, he set the trap back up, and we waited for her to get settled over and over again.  Repeatedly we would scare her up and she would be free.  It was not until we were about to give up, that finally after scaring her up she was caught.  I’ve never seen Bridger move so fast! He was down and got a hold of her in seconds.  There was no chance she was getting away this time. Each time that Bridger had to repel down, he would also have to climb the rope back up, which was pretty demanding, even for Bridger, so he was determined to make this his last time down. Once caught, we take blood and feather samples of the peregrine and take measurements of her bill, wing, tail, and legs.  Then we band them and put a geolocator on them and let them free (after Bridger has replaced the eggs in the nest of course.)

Its pretty amazing how we use the nests to trap the peregrines.  The seasons getting close to the eggs hatching, so it’s getting to risky to capture many more, but it has been an exciting process so far. We’ve checked out some eyries north of Thule along the coast, but haven’t had much luck.  I’ll let you know if we have any more exciting peregrine adventures.

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