Saturday, September 27, 2008

Colour-banded Cooper's Hawks

One of my favourite projects during July is working with Cooper's Hawks.

These small secretive hawks are not often seen by many people as they sit silently high in trees and watch you walk right by.

Cooper's Hawks are a bird eating raptor, eating birds like pigeons, robins, and sparrows. Adults have blue-gray backs and heads, with a white belly with orangy markings along their breast. They also have long thin bright yellow legs. COHA are cool because they exhibit a high degree of reverse sexual dimorphism. This means that female Cooper's Hawks are usually much larger than the males.

Another species that is very similar to the Cooper's Hawk is the Sharp-shinned Hawk. COHA are larger than SSHA, but small male COHA and larger female SSHA can be fairly close in size. One diagnostic feature if you get a good look at a sitting birds (which rarely happens) is COHA have a distinct grey cap that contrasts sharply with their back. The top of the head of a SSHA is the same colour as its back, so it does not contrast. In the hand, this difference is very evident.

My project with COHA is simple. I trap the adults and band them with special colour bands so that I can identify individuals again without having to recapture the bird. I trap them at their nest so we can learn how if adults come back to the same spot to raise their young and for how long.
For example, seen below on the left is 3/A (her red band number), a female Cooper's Hawk, and on the right is O/K, a male Cooper's Hawk. My mom and I captured these in Wascana Park at their nest in 2006. In 2007 I saw 3/A back in the same area but could not find her nest. But in 2008 I found both 3/A and O/K at a new nest together and they succesfully raised 3 chicks. We will wait and see if they both return in 2009.

We also band the young birds in the nest and observe the nestlings after they fledge (leave the nest). Again we can identify birds as individuals because of the red band so we can tell which chicks stick around the nest after they can fly and for how long.

Wednesday, September 24, 2008

Installing FEHA nesting platforms

This year, while banding Ferruginous Hawks (FEHA) around Morse and Herbert we found a few large nests that had been completely blown out of the tree and were destroyed, like the one shown below. We usually found dead chicks littered on the ground around the nest at the same time.

In an effort to create some permanent, reliable nesting locations for FEHA, we decided to install 7 artificial nesting platforms for this species to use - and that's just what we did. Artificial nesting platforms have been used extensively in the Bitterlake PFRA pasture and with great success. Many the platforms we are monitoring were succesful this year.

With the help of Randy, Lori, and Mike from Hebert/Morse, and Lorne Scott and Kristen from Indian Head and Regina, we were able to get all 7 platforms installed in one day.

We assembled the platform part of the nest earlier in Lorne Scott's workshop. On the day we had an auger rented and had acquired 7 large poles from Swift Current. When all was ready we had a full convoy of 2 trucks and 1 van packed to the brim.

We had already made contact with the landowners and proceeded to the designated locations.
While a few of us augered the hole for the pole, others connected the platform to the pole.

Then we hoisted the platform up and into the newly dug hole. The digging of the hole varied from our first hole (in sand) which took 5 minutes to dig through, versus our second hole of the day (in clay) which took closer to 45 minutes. After the first platform was installed we thought this would take no time at all.... until we started the second pole.

Once the platform was up we added lots of sticks, grass and of course, cow manure. We wanted the platform to appear as though a hawk had already nested here before. Why cow manure you ask? Well, we are not really sure why the birds do this, but FEHA regularly place pieces of dried cow manure in their nest. So again, to make it appear as though FEHA's had used this nest in the past we added the manure!

Just in case you are wondering, the Danger sign was brought for aesthetic purposes.

We placed 4 of the nests in areas where this years nest had been destroyed and placed a few nests in spots that are over run with Richardson's Ground-squirrels and no trees or nests are present.
We anxiously await the return of the hawks next year to see how many platforms are used.

Wednesday, September 17, 2008

The 6 Pack Nest

In June 2007, Lorne Scott and I went to Morse to band young American Kestrels in nestboxes that local school students had put up in previous years. Here we met the amazing Lori Wilson and Randy McCulloch. After banding the kestrels, I was mentioning to Lori and Randy about how I had been banding Ferruginous Hawks the previous week. The two locals quickly told me about three nests they knew of very close by that they would be pleased to take us to to band.

We made it to the first nest and banded the young with no problems. The nest was in a low (only ~6 feet) Hawthorn shrub. After this nest, Randy had to get home so Lori, Lorne and I continued on our way.

The next nest was the soon to be infamous nest - the Six Pack nest. The tree was dead, but sturdy enough to climb, I felt. From the road (0.5 mi back) we were not 100% confident if this was a FEHA nest or a Red-tailed Hawk nest, since we hadn't seen any adults yet. I decided to take both strings of bands so we could band it either way. I made it up the nest (8.8m above ground) and found FEHA chicks in the nest. So to make less clutter in my pouch I dropped the RTHA bands down. Oops! I dropped the FEHA string!! So I had to hoist up the FEHA bands with the owlovator and began banding the young. At first I thought I was looking at a nest of 5 chicks, but soon realized there was actually a sixth birds sitting behind the fifth chick!
I couldn't believe my eyes!! I had never seen six chicks in a nest before! Of course we didn't bring any cameras out to the nest so poor Lorne and Lori had to walk all the way back to the van and get the camera so we could document this nest. I wasn't sure if this was a big deal but didn't want to miss a photo opportunity like this.
Well it turns out we couldn't find any other published accounts of a nest with six FEHA chicks! This was a first!!

Later in July we returned to the nest and were very pleased to see six fledged chicks take off, one at a time, from the bank of the slough, seen below. We could see they were juveniles and we could see all their bands! They had all survived. In the photo below the nest is on the right side of the tree clump.
I later wrote up this account and it was published in the Journal of Raptor Research 42:152-153.
Contact me if you would like to read a copy of the published account.

Well, understandably we were quite excited to get back to the six-pack nest this year (2008) and see how many chicks were present.

We met up with the local landowner and his family and made our way over to the nest.
Up the old dead tree I went, (I don't think I want to climb this next year), and we found four good healthy chicks.

We were slightly dissapointed about finding only 4 chicks, but were pleased the nest had still produced this many chicks. It's amazing to think this nest has produced 10 chicks in the last two years!!

I will keep you updated to the story of the six-pack nest for years to come!

Ferruginous Hawks -2008

The Ferruginous Hawk (FEHA) is North America's largest hawk and definetly my favorite bird to study!!
This year FEHA's had an exceptional reproductive year, producing roughly 3.01 chicks per nest. When gophers are abundant (FEHA's favorite food source), which they were this year, FEHA's do very well. A family of Ferrug's have been known to take over 500 gophers in a single breeding season. When you have up to 6 chicks you have to keep all those mouths fed!

This year I banded FEHA around Maple Creek, and between Herbert and Mortlach.

This was the second year of my banding project that is looking at productivity and long-term territory use by FEHA in the Bitterlake area (NW of Maple Creek). For this trip Adam Crosby and Joseph Kotlar joined me and we had a blast.

In this very defined area we banded 77 FEHA nestlings.

One new element to this study is this year we banded the chicks with the regular aluminum bands but we also placed blue aluminum bands on the left leg 0f all the chicks. I hope to collect disperal data by banding with the blue bands - in other words, we know were the chicks grew up, how far away are they found as adults nesting? If one sees an adult with a blue band, we can tell you it came from a very small area and see how far away it is.

Lori Wilson, Randy McCulloch and Lorne Scott also help me find nests in the Herbert/Morse area and of course helped band.

In total I banded, with the help of many voluntters a total of 222 Ferruginous Hawks this year. Thanks to all the folks who help find nests, and band these great hawks.

Below is a dark phase adult FEHA we found at a nest near Piapot, SK. Both the adults at this nest were the dark phase colouration (aka - melano adult). Can you see the aluminum band on the birds right leg? (I know the photo is small but it is banded). This was the second year we found a banded melano adult at this nest, which means that this same bird was here two years in a row.