Friday, March 6, 2009

Tiny, tidy.

I stood for an hour, listening to the CBC on my little radio, which was hanging by a strap from one of the knobs of the tripod. The CBC will sustain you, if you let it. I was waiting for the Black-capped Chickadees to come to their nest hole-in-progress, which they seem to do every morning at about 11 AM.

How can they make such a perfectly circular hole?

Chickadees often act as primary cavity nesters (i.e., create their own nest holes). But since they lack the size and excavating equipment of, say, a flicker, they require a tree with relatively soft wood. A paper birch snag in an advanced state of decay is suitable, provided it’s not on the verge of collapsing. This hole is about twenty feet up, three feet below the broken top of the snag.

Chickadee entering hole.

Finally, at 10:58 (Chickadees are not only dapper, they’re punctual), a pair appeared and landed in a neighbouring tree. One darted into the hole, and disappeared for a few seconds. Out it popped, with a scrap of pulpy wood in its bill.
Click to see wood chip in bill.

It flew away, carrying the wood. Immediately the second bird flew into the hole, and it too darted out quickly, carrying a scrap of wood in its bill.

There was a lag, as they went somewhere. Chickadees are so tidy, they probably took the wood chips to a recycling depot.

This happened again and again. They arrived together, entered the hole to remove more wood in quick sequence, and then disappeared for a few minutes. Perhaps, in arriving and leaving as a twosome, instead of as two individuals with evenly spaced intervals between, they are keeping a lower profile, acting almost as a single bird, which would draw less attention to their nest. They would also be affording each other the protection of a pair of eyes on the outside--they got each other’s back. I can understand these things.

What I don’t understand is how they can make such a perfectly circular hole.

4 comments:

themanicgardener said...

It's a mystery. These are great photos. Thanks for being so patient.
--Kate

PSYL said...

Interesting. I definitely learned something from this post today. I will need to keep an eye out for Chickadees' nests next time I am out. Great post!

Maybe they have a watch and a circle-making compass? That would certainly explain why they are so punctual and capable of making such a round hole. We just have to find an answer to where they keep the watch and compass now. Haha.

KaHolly said...

Your patience paid off with great photos. I learned something new! I assumed they took over an already existing hole! I will see Black-capped Chickadees through new eyes now.

barefootheart said...

Awesome observations.