Now we see them, now we don’t
by Linda De Kort
Every December, on specific days, members of local Audubon Chapters gather in small groups to observe and record the numbers of birds seen and heard within a defined 15-mile radius circle. This information has been gathered and recorded for over a hundred years nationwide and gives us a good picture of changes that might not be obvious on a small scale, but abundance patterns can be observed over the decades. One of the small birds we enjoy observing on these “Christmas Bird Counts” has an unusually “cute” scientific name: Spinus pinus; its common name is Pine Siskin. Pine Siskins are especially interesting because their populations change so dramatically from winter to winter. Sometimes we see them, sometimes we don’t.
Last year on the Bigfork Christmas Count, we had 358 (most ever) Pine Siskins and this year we had only 33! Even more startling was the difference in numbers on the Kalispell Christmas Count. Last December, 742 individuals were counted on that one winter day; this year we had only 15. Pine Siskins have been seen on the Kalispell Count for 20 of 21 years. The low count was 0 and the high count occurred last December.
When the winter population count is unusually high, it is called an “irruption”. We are assuming that these birds are irrupting from their northern and higher elevation homes in search of more abundant food. We seldom regard our Flathead Valley as a banana belt, but these little birds, like a few other bird species that breed in Canada, come here (sometimes) to spend the winter. They come in droves when the seed crop up north is scarce; this year, the conifer crop up north must be plentiful which might be why we have seen so few. The bitter cold of northern Canada and Alaska does not seem to bother them. They have an uncanny way of increasing their metabolism to withstand sub-zero temperatures all winter long. One study showed that Pine Siskins could increase their metabolic rate up to 40 percent more than a typical songbird to survive temperatures as low as -94 degrees Fahrenheit.
Pine Siskins are not territorial and we usually see them in large flocks while feeding and even nesting. The flocks fill the air with their raspy chatter, which is punctuated with a loud ascending zipper like sound. They have delicate beaks well suited to “tweezering” out conifer seeds from cones (as their name implies) as well as small seeds from flower heads. Backyard feeders with thistle seed are one of their favorites. The delicate beak of the siskin distinguishes it from other brownish, streaked birds. Siskins are also smaller than most finches and sparrows, only about 4.5 inches from tip of beak to tip of tail. Both male and female have bright yellow markings at the base of the tail and on the wings that are most conspicuous when they are in flight, flittering at the feeder or during courtship. The male and female have very similar markings so it is very difficult to distinguish them from each other.
Pine Siskins generally nest in open coniferous or mixed forests; their breeding range often changes. The exact time for courtship also seems erratic, based mostly on the availability of food. The male feeds the female during courtship, nest building and incubation. The nest is an open cup, well-hidden on a horizontal branch of a conifer. There are up to 5 greenish-blue speckled eggs, which hatch in about 13 days. The young leave the nest when they are only about 15 days old. In researching the literature for this article, I came across a study recorded in 1887. I discovered that over a century ago, Pine Siskins were commonly known as Pine Finches; the most glaring discovery however between then and now was the manner of study. The researcher of 1887 was so thrilled to observe the nest building of a pair of “pine finches” that he sent his young nephew up to the nest to retrieve it along with the eggs. He then shot the frantic parents who were perched close to the nest they were trying to protect; he needed them to complete his “collection!”
Now evidence is warning us that these precious birds are on the decline worldwide not because we are making “collections” but because we are warming the planet. These small creatures, who are adapted to withstanding temperatures as low as -94˚ F, are not tolerant of high temperatures. Audubon’s new, ground-breaking report, Survival by Degrees: 389 Bird Species on the Brink, shows that two-thirds of North American bird species are at risk of extinction from climate change. But if we act quickly to reduce greenhouse gas emissions, we can help improve the chances for the overwhelming majority of species at risk, including the capricious Pine Siskin.