Wednesday, January 28, 2009

Recapturing a Banded Great Gray!

We were very excited when we captured our first Great Gray Owl with Harold Fisher this past weekend. We were even more excited when we realized it was already banded! We were then even more excited when we found out when and where this bird was originally banded!

This girl (we think), weighed in at 1274 g, with a wing chord length of 441 mm.

Can you see in the picture how some the flight feathers (the largest feathers on the wing used to fly) are different shades of grey, some are even brown? This means that this bird has different generations of flight feathers, which is a technique that is used to age certain species of birds (this has been mentioned before with saw-whets).

Based on the number of feather generations in the wing of this bird, we estimated that this bird was atleast 3 years old.

Well, were we surprised to find out later that day that this bird was originally banded on 24-Feb-2001! That would be eight years prior to our capture of her. Because she was aged as atleast one year old when she was first caught, we know that this bird is atleast 9 years old! The oldest longevity record for the Great Gray Owl is ~12 years.

Interestingly, she was captured initially only 64 km S of where we captured her!

Recaptures like this are what researchers like Harold are looking for. This data will help us understand movement patterns of these owls between seasons (many seasons in the case of this individual!) and understand population dynamics (how old birds live, the proportion of young birds captured versus older birds captured, etc). It was fantastic to be part of this find!

A Great Gray Experience!!

Great Gray Owls are one of the most majestic birds on the planet, if you ask me, and it wasn't until just this past weekend that I actually got to see one in the wild!
We joined Harold Fisher of Prince Albert (a local raptor bander) for the weekend as we toured around the countryside to find these huge owls as part of an ongoing banding project. For a number of years now raptor banders have been catching and banding Great Gray and Northern Hawk Owls in the boreal forest in an attempt to learn a little bit about these elusive owls.

Harold did not let us down - on our first day we located 4 Great Grays!!

Of these 4 owls we were able to capture 2 Great Gray Owls, plus 1 Northern Hawk Owl - according to Harold this is a good catch in one day! You can drive for hours and hours and not find an owl. Once in the hand, the birds are banded, weighed, measured and photographed. And then quickly released, take a look at Kristen's first time release.

Great Gray Owls hunt primarily small mammals (mice and voles) during the day. You'll notice these owls have very large facial disks (the circular shape around the eyes), which aid in focusing sound into their ears (cup your hand over your ear, you notice you can hear better? This is what the facial disk does). Because of this adaptation Great Grays can hear a mouse below the snow, dive in without ever seeing the mouse and come up with a delicious meal!

While they appear large (they are the largest owl in North America), they are not the heaviest on the continent (Snowy or Great Horned Owls take that prize). Great Gray appear so big because they have so many feather to help keep them warm during the cold winter up north. In the picture below you can see Kristen's hand holding onto the birds legs (the safest way to hold the owl, both for the handler and the owl) - the hand in the glove is actual cold, while the hand tucked up in the owl's feathers are amazingly warm and toasty!

It was amazing to get to see a Great Grey Owl finally! It was even more amazing to get to handle one of these impressive raptors. In the hand, the Great Gray is as docile as a bird can be!

Thanks to Harold, Denise, and Shelley we had a great experience!