Wednesday, May 27, 2009

To Last Mountain Bird Observatory

This spring and last fall I have been helping band songbirds at the Last Mountain Bird Observatory (LMBO) which is situated at the north end of Last Mountain Lake between Govan and Nokomis, Saskatchewan.

LMBO is a fantastic little banding station nestled in the Last Mountain Regional Park that focuses on monitoring migrating songbirds like warblers, sparrows and flycatchers. LMBO has been in operation for 20 years now, gathering valuable information on migrating songbird population trends.

Kristen and I were up at LMBO the past two weekends and will be there again this weekend. Interestling spring banding at LMBO is fairly quiet compared to fall banding. Spring is unique though because we catch many of the warblers and other species in their bright, bold breeding plumage, which is very cool to see! Unfortunately, overall daily captures are significantly lower then in the fall. So we don't catch many birds but they are pretty when we do!

If you have an opportunity to visit LMBO I would strongly encourage it. Nature Saskatchewan currently manages LMBO and you can get more information from their website. I am also one of two editors of the Black-and-white Warbler Newsletter which is a publication that highlights what is being caught at LMBO and in general what is going on. There is information there regarding dates that banding is happening and lots more.

Here are a few birds we have captured the last few days I was out.

Brown-headed Cowbird - Male

Tree Swallow

Yellow Warbler - Male

Gray Catbird

Common Yellowthroat - Male

Wednesday, May 6, 2009

Eggs have been laid

On Monday evening (May 4), Kristen, and I, along with our friends Darla and Mattea headed out to check on a few of our American Kestrel boxes. We had an enjoyable evening and managed to capture a few adult females.

(Here is Mattea with one of the female American Kestrels,
before we placed the bird back in the box)

In total we checked 3 boxes. Two of the boxes contained 2 eggs (so the females are still laying) and to our surprise, one of the boxes contained 6 eggs!
At this time last year, all the clutches were completed, so the birds seem to be quite behind in their nesting season (except for the six clutcher). This is likely due to the cold spring we have had. Here is a photo of the 6 egg clutch.

As described before, American Kestrels lay on average 4-5 eggs. The female will lay the first 4 typically without beginning incubation. Once the 4th (usually out of 5) egg is laid the female will begin to incubate. Then a day or two later, the last egg will be laid. This means that when we go to band the chicks later in June, four of the chicks will be roughly the same size having hatched on the same day typically, and one will be a little bit smaller having hatched a day or two later.

It will be interesting to see how the relative age of the chicks compare in the 6 egg clutch. Did the female begin incubating after the 4th egg was laid or the 5th?

When incubating eggs, female birds (typically the sex who primarily incubate the eggs, but not always) lose the feathers on their belly and at the same time their skin on these bare spots becomes loose and very fluidy. This helps the skin sort of wrap around the eggs, to maximize the amount of heat that can be transferred from adult to egg. American Kestrels develop 3 such brood patches. One develops on their lower belly, and two on their sides closer to their "armpits". In most monomorphic species (males and female look identical) the brood patch can be used to determine if the bird is female. However, in some species males develop a full or partial brood patch as well! In kestrels, males can develop partial brood patches.

Here is a photo of the medial brood patch on one of the kestrels we caught the other day.

Monday, May 4, 2009

O/K is Back!

We have been watching Wascana Park closely for the return of our pair of colour banded Cooper's Hawk. We banded the male (red band O/K) and the female (3/A) in Wascana Park in 2006 at their nest. In 2008 the pair were together at another nest in Wascana.
We were anxiously awaiting their return this year.

Finally one of them showed up on Thursday last week! We were beginning to worry that they both had perished and no one was going to return.

On Thursday morning, we found O/K breaking sticks off of a tree and flying up to add them to his nest. He then flew from the nest and landed ontop of a female, who we hadn't seen yet, and copulated with her. After this, he continued his work of breaking off branches and adding them to the nest, as his mate watched.

We moved closer to see if we could see if the female was banded. After getting a really good look at her legs, we concluded that she was not banded. So 3/A has not returned.... yet, perhaps. We are not sure if she has died, or if she has moved to another territory with another male, or is still migrating.

Regardless, O/K is back in Wascana for his 4th summer with a new mate! Exciting stuff, if you ask me!!

This is a photo of O/K when we first captured him in 2006.