The vegetarian goldfinch

The goldfinch started tapping at my window on July 4. I work at a desk looking out at the swaying fingers of goatsbeard flowers, formerly white and fluffy but now brown with tiny seeds. The goldfinch liked to sit among the goatsbeard, occasionally plucking a seed. Several times a day, she flew over to the window, clung to the sill, and pecked at the glass.

I knew it was a female because the field guide showed a male with a black-capped head, unlike this one, which was also not so brilliantly yellow as the male. At first, I thought she was trying to get inside, but I didn’t think she’d like it indoors, so I steadfastly refused to open the window. Then I remembered Google. I tried the phrase “goldfinch tapping at window,” and it turns out lots of people are driven crazy by goldfinches tapping at their windows. I don’t mind—I liked getting to see her six inches away—I just wondered what she wanted.

She wanted a mate, according to the bird forum, or else she was guarding her territory. She saw her reflection in the glass and thought it was another bird. But we’re dealing with a special situation here. Practically all the other birds were done with finding mates and setting up their territories by the end of June. Goldfinches nest late, and it’s for a particular reason—they are vegetarians!

Most birds feed their young with worms and insects, solid protein for growing babies, so they nest in spring. Goldfinch babies get their protein from seeds, so their parents have to nest and mate in summer, when the seeds mature. That’s why there was a goldfinch tapping at my window in early July.

And here’s a related fact about cowbirds, those avian parasites that lay their eggs in the nests of other birds. When the babies hatch, the large, aggressive cowbird chicks grab more food than the resident nestlings, which may die. However, cowbirds are not vegetarians. The ones that end up in goldfinch nests die within three days because they can’t survive on a diet of seeds.

There’s some kind of deep lesson here—if only I could figure out how to apply it.

After a few days of nibbling at the goatsbeard, the goldfinch began to pluck entire strands of seeds from the bush. She’d yank one out, and then at least two more, holding them all in her beak. Sometimes she dropped one while grabbing another, but she always ended up with three. Once fully loaded, she’d fly away to the west and disappear among the leaves of a big oak down the road.

Often she’d come over and peck at the window before harvesting the strands of seeds, making sure that nasty, ghostly rival didn’t get any of her loot.

I suspect she was using the goatsbeard stems to build her nest, since she disappeared after about a week. I miss her. I hope she’s been sitting on her eggs and will eventually return with fledglings to feast outside my window.