On tumblr, where I spend an increasing amount of my online time, I keep seeing a post about Gouldian finch chicks. It claims that these birds have phosphorescent spots on the sides of their bills to help guide the parents to the baby's food hole. We have, and breed, Gouldian finches where I work, and I'd never heard of this. Surely if we had baby birds with glow in the dark spots on their faces someone would have mentioned it to me.

So when I was at Bird's World recently, I told the keepers there about this ridiculous tumblr post. "Yes," they said in chorus, "you can see it right now if you want."


So a coworker pulled down a nest box, opened it up, and let me see the glow.


The effect is even more striking when the chicks' mouths are open, but you get the idea. However, a quick side trip to wikipedia quashes our fantasies of a bioluminescent bird:

http://en.wikipedia.org/wiki/Gouldian_finch
"Very young birds, like many other species of Australian cavity-nesting finches, have a variety of odd features in and around their mouths including a "palate marked in the fashion of a domino" and several "prominent rounded tubercles" with an "opalescent lustre" at the back of the gape. These tubercles are commonly (and incorrectly) described as phosphorescent in spite of much scientific evidence to the contrary.[4] It is believed that these tubercles simply reflect light and are not luminescent.[4] Scientists have hypothesized that this domino-like palate and striking tubercles may facilitate feeding within the dark confines of a nest cavity, although no experiments have been conducted to support this idea."

footnote [4] is: http://www.jstor.org/discover/10.2307/2421636?sid=21105707320511&uid=4&uid=2

photo by cottonmanifesto

Urban species #051: American goldfinch Carduelis tristis

During the spring and summer, the male American goldfinch is bright lemon yellow, with a black cap on the front of its head. The rest of the year, the male and female look similar: dull olive with black wings marked with white wing bars.

The goldfinch lives almost entirely on seeds. Seeds of plants that gardeners consider weeds provide most of its diet. The large plant family Asteraceae contains many important weeds that goldfinches and other birds feed on, including common urban plants such as dandelion and thistle. Because these seeds are most abundant in the late summer and fall, the goldfinch has adapted to have the latest breeding season of our songbirds. As for winter food, Cities landscaped with the right plants can provide it for them: birch and alder seeds do the trick. Of course, humans feed goldfinches as well, buying feeders specially designed for them. These are filled with the sterilized seed from a Ethiopian plant (in the Asteraceae family) called niger, but often sold as "thistle." American goldfinches are the among the five most common birds reported to the Massachusetts Audubon Society's eBird program.

The American goldfinch is the state bird of the most densely populated state, New Jersey, and also Iowa and Washington. There are at least five other species of Cardeulis finches in North America, including the lesser goldfinch (C. psaltria) of the southwest, and the common redpoll.


Photo by urbpan. Male American goldfinch in breeding plumage (this entry edited to add it), in May.