For the Birds Radio Program: Pine Siskin
Pine Siskins This winter, Pine Siskins are everywhere in Ithaca, New York. They arrive at first light and pig out at the feeders on my balcony until late afternoon. A few weeks ago there were 5 or 10 at a time. Now there are 50 or 100.
Pine Siskins are an irruptive species. Although at least a few are found most months and most years in Duluth, they appear in Ithaca more irregularly, so here they were a hotline bird at first, and even now one or two people are writing about them just about every day on the Cayuga Lake birding listserv. Pine Siskins are closely related to goldfinches and redpolls, though are by far the most dully colored of their genus. Many of them look like dull streaky sparrows, only with a finchy, notched tail and a surprisingly narrow bill. Some have bright yellow wingbars and tail markings, but many do not; it’s virtually impossible to distinguish the sexes in the field because there is so much overlap between male and female plumage. When not at feeders, they are often heard from spruce and pine trees. They can stay so well hidden that it sounds almost as if it’s the tree making all the twittering sounds.
The siskin’s close relative, the American Goldfinch, is as close to a true vegan as any bird. Apparently goldfinches never seek out animal food, and eat only insects that inadvertently happened to be in the wrong place on a seed at the wrong moment. Pine Siskins eat far more plant than animal food, but about 1/6th of their diet is insect. Unlike goldfinches and redpolls, the siskin’s narrow bill has trouble cracking open hard seeds, so siskins are less likely to take striped sunflower, which has a thicker, harder shell than black oil sunflower. As with their relatives, they’re especially partial to nyjer seed.
Pine Siskins are peaceable birds, but there’s something of an aggressiveness continuum, and the ones at the far end can’t help themselves—when they make eye contact with another siskin they try to drive it away, which they do by opening their wings and raising and widening their tail to expose the yellow. If that doesn’t drive the other bird away, they lower their head, open their mouth, and charge. If the other bird doesn’t instantly fly off, the first bird hits, and the two of them end up boxing in the air for a moment. The brighter the yellow, the more effective the display seems to be at chasing birds off without coming to blows, so I seldom see siskins even try it unless they have more yellow than average, and the birds that don’t budge and end up fighting with them tend to have more yellow than average, too. When food is abundant at a feeding station, this aggressiveness is rather a waste of time and energy, and the vast majority of siskins wisely stay focused on eating, keeping their backs to one another so they don’t get urges to attack or elicit anyone else’s attack in the first place.
Pine Siskins stay in tight flocks and are constantly twittering, which draws the attention of other birds. And siskins seem to expect the best of other birds, figuring that at the very least, any bird would have the courtesy to spread its wings and tail before attacking. In spring, grackles often walk amidst a flock of feeding siskins and suddenly stab one in the skull. They usually just leave the poor bird, not even eating it. Crows do the same thing, but at least then carry off and eat their plunder. When the temperature drops to double digits below zero and birds are out there, naked as jaybirds, it’s easier to appreciate the Jack Londonesque world of “kill or be killed,” but even so, seeing one of these attacks is gruesome and sad.
Fortunately, siskins stay numerous, thanks in part to their early nesting season. Already many of them are making their ascending buzzes that are, for a siskin, the finest love songs. By Valentine’s Day they’ll be totally twitterpated, and by April, even in the cold north many will be nesting. Their lives may be short and hard, but they seem to grab a lot of gusto while they can.