Thursday, July 30, 2009

How do they know?

I am writing this at 10:40 a.m., though it will not post until 1 this afternoon. But right now, in our tiny patio garden, a goldfinch is breakfasting happily on seeds dug out of sunflower planted by other birds during the winter. Goldfinches have visited our yard before, usually for the same reason. It seems that if we have sunflowers in the yard, goldfinches will know about it. But no goldfinches actually seem to live around here. There are plenty at Tinicum Marsh, which is about a 20-minute drive from here. So how do they find out, I wonder. Birds have wings, of course. So maybe they just do reconnaissance flights. They may just be smarter and less the prisoners of "instinct" than we think.


  1. I never underestimate the cognitive resourcefulness of birds. For example, we have hummingbirds who visit our regularly refreshed feeders from time to time, usually during the migration seasons, and I always wonder: How do they remember where to find the feeders? Out of all the sensory and navigational inputs that must be surging through a hummingbird's tiny heads, the hummingbirds unerringly "know" how to find the humbly provided nectar in feeders that hang from out back porch. How do they do it? I have absolutely no idea. But, when I think about for a while, I somehow find myself thinking about the works of Wordsworth and other English Romantic poets (especially Keats). If I had more time, I would develop the connection more clearly, but I suspect you get the idea.

  2. Hi Frank,

    You got me wondering how ants know that I left a crumb behind on my countertop.

    So I found this: Deborah Gordon digs ants.

    It turns out that early in the morning, a patrol ant shows up and finds the crumb. On the way back, it leaves traces for the forager ants to follow into the house, onto the counter, and to the crumb. The forager ants will do this if the patrol ant gets back to the nest, so they know it is safe. The foragers don't eat the food, but bring it back to the nest, so that it gets to the larvae.

    Apparently, this is similar for birds as well. There is a site I just found called The Straight Dope, where one can ask such questions about how birds find bird feeders, and someone did. Here's part of the answer:

    Small seed-eating birds probably cruise the neighborhood regularly in search of food, both individually and as members of flocks. It's quite likely they recognize a standard bird feeder as a highly concentrated source of food, not because they have evolved to do so, but on the basis of experience with similar feeders in the past, either in your neighborhood or elsewhere.

    So we have patrol birds finding the food, more than they can eat, and calling back to others that dinner is served.