Tuesday, June 23, 2009

Banding Ferruginous Hawks

Over the last two weeks we have been crossing all over southern Saskatchewan banding Ferruginous Hawks. This is my favourite time of year!!!

Just like everything this spring, Ferruginous Hawks are about a week or two later than usual. By this I mean that for this time of year the young birds are about a week or two younger than I would expect at this time.I have not crunched all the numbers yet, but preliminary results suggest that FEHA are doing quite well this year! We are finding a number of nests with 5 chicks, which is a big clutch for any hawk!Last year we placed blue aluminum bands on FEHA in the Bitterlake/Maple Creek area. This year we are placing alpha-numeric blue aluminum bands on FEHA from Maple Creek to Estevan. These bands allow us in future years to be able to identify our banded birds using a spotting scope or binoculars. This year we have noticed 4 banded adult FEHA's. If these birds had alpha-numerics on their legs we would know where exactly where and when they were originally banded. To find out where these birds were banded we have to catch them, which is not easy!One reason these hawks are doing so well, I believe, is because there are so many Richardson's Ground Squirrels around. These birds are ground squirrel specialists! Interestingly we have only found only 3 different kinds of prey items in the nest. Below is a photo of what we found in one nest and represents the items we have found: Richardson's Ground Squirrel, Thirteen-lined Ground Squirrel, and Northern Pocket Gopher.
A family of Ferruginous Hawks will eat over 500 Richardson's G.S. during the summer!! As a landowner, you want Ferruginous Hawks nesting on your property! Just imagine if the Ferruginous Hawks that were nesting on your land were scared off and didn't raise their young on your land... 500 ground squirrels would be able to survive. Now imagine how many ground squirrels can be produced by 500 ground squirrels. A female ground squirrel can have 5-6 young. So assuming that 250 of the 500 ground squirrels are females, producing 5-6 young each, you will have 1250-1500 new ground squirrels produced that year. Now, in the following year, how many more young will be produced by 500-750 new young females? So you can see how beneficial these guys are to have around!!

Here is one of the more interesting nests we banded at this year. We found this nest in 2008 and it was active again this year.

There will be more to follow on Ferruginous Hawks.

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