Home sweet home

It’s nesting season for some of the resident birds. Having staked out a territory and driven off the competition, it’s time to find that perfect little home in which to raise the kids this year.  For some species, the safest place is a cavity in a tree or nest box, where the offspring will hopefully be safe from predators.  The other day while I was down by the pond in the far backyard looking at turtles, a pair of Black-capped Chickadees were flitting in and out of a notch in a dead branch just a few feet away.

black-capped chickadee-at its nest hole

Each one of the pair entered the hole completely silently (no vocalizations) and then exited a few minutes later with a beak full of wood chips.  It must have been a pretty roomy nest cavity because a couple of times they were in there together.

This cavity may have been used by a previous owner (e.g., a woodpecker) because the entrance is quite a bit larger than the chickadee is.  Nevertheless, this pair is modifying the cavity to suit their needs this year — for example, the typical cavity for a chickadee nest is about 8 inches deep.  After excavation, they will add a layer of moss and small sticks, and then another layer of soft fur to line the nest cup.  It’s quite a production.

Black-capped Chickadee leaving nest hole

They were furtive and silent as they went about their task, — better to keep potential predators from coming back to raid the nest sometime later.

But the number of suitable cavities of just the right size are limited, and there are lots of chickadees, House Wrens, Tree Swallows, and Bluebirds that require one about this size to start building their nest.  While I was watching the courtship activities of the osprey pair at the marsh the other day, I saw some of this interspecific competition between chickadees and Tree Swallows, each of whom seemed to be claiming a cavity in a tall, dead snag.

Black-capped chickadee entering nest hole

A pair of Chickadees were entering and leaving the hole with wood chips in their beak, — completely silently.

Black-capped chickadee leaving nest hole-

Definitely some construction going on there.

tree swallow at chickadee nest cavity

Meanwhile, when the chickadees departed to get rid of their wood chips, a Tree Swallow investigated the cavity.  Unlike the chickadees, three Tree Swallows swarmed around this cavity vocalizing loudly.  They entered and exited very quickly — did they recognize this home belonged to someone else?

Tree Swallows checking nest hole

This shot was taken when one chickadee was still inside, with the Tree Swallow poking its head down into the cavity to observe whose home it was.

I didn’t stay to see who got control of this cavity.  Tree Swallows are a little larger than chickadees and weigh about 50% more, so it’s possible they might have ousted the chickadees and claimed this cavity for their own home.  I’ll have to check back later to see who “won”.

6 thoughts on “Home sweet home

  1. I was walking in some meadows with nest boxes and the competition was fierce among the tree swallows for boxes – aerial battles that would end up a tangle on the ground. The bluebirds were comparatively mellow, because the nesting pairs didn’t yet outnumber the boxes. The nest boxes were in pairs side by side – and blue birds and tree swallows don’t mind living side by side – though they won’t put up with their own species so close.

    • I’ve seen that same thing here too. Those Tree Swallows are pretty aggressive, especially toward each other. In my area, the bluebirds get just a little bit of a head start over the Tree Swallows, and sometimes have completed their nest building by the time the Tree Swallows arrive. The other species that gets involved in the fray is House Sparrows, which I have seen eject TS eggs, and start a new nest cup of their own in a TS nest box. I’m not sure they try that with the bluebirds though because they (BB) are somewhat larger-bodied.

  2. White-breasted nuthatches are building a nest in an owl box that I put up several years ago in our yard. It’s a large cavity obviously, so we’ll see if they can defend it against larger takers. As far as I know the box has only ever been used as winter lodgings for squirrels. I was intending to take the box down so I could re-mount it in January. Maybe for once it would be free of squirrels when the owls are nesting. I’ll have to wait until the nuthatches are finished.

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