Saturday, July 15, 2017

Bird House Wren

House Wren

Shelley's Dad made a batch of bird houses and they put up a couple in our yard. One was right beside our shed and back gate and I was skeptical that a cautious bird would choose to use it. But it soon filled up with twigs and obviously something was building a nest, although I never saw the builder. Then one day when I was getting my bike out of the shed I heard a lot of cheeps from the box - hatchlings. Twigs blocked part of the entrance, and it was dark inside so you couldn't see them.

Watching from my office window I finally spotted a parent coming and going feeding the babies. I haven't figured out if it's one parent or two doing the feeding - I've only see one bird at a time. (Audubon says "probably both parents feed nestlings")

House Wren with a beak-full of bugs

It think it's a House Wren. I've probably seen them before but from a distance they're just another sparrow-like bird flitting about, although they're a little smaller than a sparrow. When you get a better look in the photos, they actually have an attractively patterned tail.

I was amazed at how often the parent returned to the nest with food. They're obviously very good at finding and catching insects. It's also amazing that the babies can process food at that rate, although it is being shared with probably 6 or 7 of them. It was as quick as 15 or 20 seconds between visits, or as long as a minute or two. Visits were quick and if you glanced away you could easily miss a visit. If you were within hearing you could tell when the parent was feeding because of all the cheeps from the nestlings. The first day I was watching the parent would go completely inside the bird house to feed them. But a few days later the nestlings are getting bigger and they come close enough to the opening that the parent can feed them while perched on the edge. The feeding frequency seems to have slowed down as well.

Of course, I had to try to take some photos. I got out the big lens, tripod, and gimbal head. At first I took some photos from my (open) office window. But even with 900mm equivalent the bird house was a bit far away for good shots. So I moved into the back yard. Our yard slopes down towards the back so I could set up sitting on the ground. I tried not to disturb them too much. The feeding continued as before so I assume I succeeded. Occasionally the parent would land on the fence or on top of the bird house before delivering a batch of food. Perhaps a nice juicy spider, or a fat moth, or a mouthful of miscellaneous bugs.

House Wren with a nice juicy spider

House Wren with a beak-full of bugs

I'm always impressed that they can collect multiple insects without dropping them, a good trick with no hands!

House Wren with a moth

This morning, the nestlings are more active and vocal, crowding around the door awaiting the next food delivery. Notice the bright yellow mouth to provide the parent with an easy target. These guys look fairly well developed.

House Wren nestlings

Of course, what goes in must come out. With that many nestlings eating that many bugs, the nest would be a mess, except that the parent carefully removes the waste (which the baby bird conveniently produces in a tidy fecal sac) Taking the waste away from the nest also reduces the chance of predators finding it.

House Wren taking out the garbage

House Wren

Despite the decent camera and lens and my best efforts, the photos aren't quite as sharp as I'd like. Not sure what I need to do different. High ISO on some, which is part of the problem. It's also a balance between small aperture for depth of focus and fast shutter to freeze motion. Getting closer would be the best solution but I didn't want to disturb the birds too much. On the other hand, these days the majority of people view photos on the tiny screen of their phone.

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