0.4oz of determination

Every fall, I buy ornamental squash from local farms. After a winter outside, they are dried out but still sculptural:

This one was disintegrating fast, and something had burrowed into one end and eaten the seeds inside, creating a useful hollow:

Two years earlier, I had fashioned a decent birdhouse from another gourd, which the wrens had cheerfully taken over to rear their brood, so I wondered if this too could be repurposed. I had heard a wren around, so I hung it in the same messy shrubby brush as before and waited.

The gourd had broken up somewhat, but still, three days later, a male Northern House Wren, Troglodytes aedon, appeared, singing like crazy to advertise to potential mates that he had taken possession of a nest site:

Here is his song:

Having found a nest site, the male starts to build a foundation of 10-400 (!) twigs (visible at bottom left) , and if he is lucky a female arrives:

They then both begin to ferry in small twigs, building from the top cavity onto this foundation. The female takes on most of the work after the foundation is complete, and indeed I only saw the two birds together at the start.

She frequently overestimated the width of the opening.

Some tricky wrestling was involved:

And sometimes the delivery just got dropped:

A few minutes later, a different twig caused new problems:

causing a regroup:

But wrens are persistent. She just picked it up and tried again,

and this time a sideways angle did the trick:

One day later, the main structure must have been complete, and she was bringing in thinner stalks

or grasses:

Pretty impressive work for a bird that weighs no more than 11g, or 0.4oz.

PS Before the female arrives, the male also often adds spider’s nests or other tiny light-colored fluffy things to the foundations, for unknown reasons: