Drama tucked into a nest
I was thrilled last Saturday when gentle tittering emerging from
one of our apple trees led me to discover a lesser goldfinch
sitting on her eggs.
Drama tucked into a nest
I was thrilled last Saturday when gentle tittering emerging from one of our apple trees led me to discover a lesser goldfinch sitting on her eggs.
The tiny cup – it could fit in an espresso cup with room to spare – is tightly woven of grass and plant fibers and lined with downy material. Leaves are tucked around it. Most of the time the only clue that the female is on the nest (males of this species do not incubate) is the tip of her tail showing over the lip. That, and that quiet tittering.
These are not the first birds to nest in our yard. Rock pigeons – feral descendants of domesticated pigeons – fancy our roof for nests. That’s something we’re actively discouraging. They are messy, and I don’t find their throaty cooing or the pitter-patter of their scaly feet on the roof over my head in the minutes before dawn to be particularly awe-inspiring.
But we have played host to an Anna’s hummingbird, a pair of bushtits, mourning doves and probably others that escaped our attention.
This newest set of “renters” is part of a flock that hangs around our place for much of the year. We keep nyjer seed in a feeder. The tiny black seeds are goldfinch favorites, and they flock to our rosemary for its seeds.
While the female incubates eggs, her mate brings food through the day.
Since the eggs only incubate for 12 days, by Monday I couldn’t resist, and carefully climbed a ladder placed nearby to check on things before the eggs hatched. I was concerned because Mary, my wife, had spotted the shattered shells of two small eggs in our driveway over the weekend.
A glance at the nest revealed why, and silently told the story of a real-life drama.
Goldfinch eggs are tiny, unmarked and colored a delicate greenish-blue. Next to the one remaining egg was a much larger egg, one marked with brown splotches on a white shell.
The egg is that of a brown-headed cowbird. These North American natives were once not found in California. They evolved to follow buffalo herds, feeding on insects churned up by the migration of vast herds. Since the buffalo did not linger in one place too long, neither did the cowbirds.
That meant they would not be in one place long enough to build nests, incubate eggs and rear young chicks. So they evolved to lay their eggs in the nests of others.
As people and their cattle moved westward, so did the cowbirds. The result has been the decline of some species. Cowbirds often dispose of some of the host parents’ eggs, and cowbird young often out-compete other baby birds at feeding time.
I quickly left the nest before disturbing the parent birds, and put my ladder away. Then the indecision started.
What should we do? Should we remove that interloping egg? Should we count on the parent birds being able to feed two young, their own and that cowbird?
It’s not a momentous decision. We’re not about to run out of either brown-headed cowbirds or lesser goldfinches, after all. Aesthetically, the goldfinches win hands down. They are beautiful, spangled in shades of yellow, olive, black and white. Cowbirds are drab. Goldfinches have a plaintive call and chatter in flight. Cowbirds have a grating screech that can hardly be described as a song. Goldfinches craft nests that would be the pride of any basket-weaver. Cowbirds steal from others.
For the time being, I opted to just leave things alone, and to consult the rest of the tribe before opting to act or to observe.
