Laura Erickson's For the Birds

One of the fairly common birds in Wisconsin and Minnesota right now didn’t even exist here until the late 1980s. Genuinely wild House Finches were not recorded anywhere in Wisconsin until 1987, and not in Minnesota until 1989. The House Finch’s original range was in the American Southwest. During the 1800s and early 1900s, wild birds were often captured to serve as pets, and people in the East eagerly bought these birds, marketed as Hollywood Finches. When the Migratory Bird Act was passed, making it illegal to trade in native American species, a handful of unscrupulous bird dealers continued to sell them. When the US Fish and Wildlife Service raided some Long Island pet shops in 1940 and 1941, the owners released their birds out their windows. The birds managed to eke out an existence on Long Island, and in the following decades slowly spread along the eastern seaboard. Then, in the 1970s and 80s, their population exploded and they started spreading inland. Now virtually all eastern House Finches are descendants of what were perhaps only a few dozen birds, and even these were probably inbred from a handful of originally caught western birds. Conjunctivitis, a horrible eye disease, has become a scourge of eastern House Finches. The birds are so closely related genetically that if any individuals are genetically prone to a disease, the entire population is more likely to be vulnerable than a normal wild population. In some areas, House Finch Eye Disease has decimated flocks. The Cornell Lab of Ornithology has an ongoing project to track diseased birds, and asks anyone who sees a House Finch or any other feeder bird with an odd looking eye to report it. You can find out how at their website, www.birds.cornell.edu. Conjunctivitis has become so associated with House Finches that many people instantly think of disease when they think of these lovely little birds. But House Finches are fascinating for many reasons. Males require carotenoids pigments in their food items for their plumage to assume the red color. The species was released on some of the Hawaiian Islands where this dietary item isn’t available—male House Finches there have virtually no red at all. Where males do show red, females prefer the reddest males. It’s believed that males who have plenty of carotenoids in their own diets are the ones most likely to provide the most nutritious resources for a nesting mate and babies, so redder males have an evolutionary advantage. Even where their numbers are small, House Finches are more likely to be encountered in groups than individually. They’re abundant in Ithaca, New York, where every day I see flocks numbering in the dozens. When I see them in my neighborhood in northern Minnesota, or see them at my mother-in-law’s feeders in northern Wisconsin, I also see flocks—it’s just not an everyday event for me in those places. In summer, whenever people call me up to ask me what the bird nesting in their hanging flower baskets, the answer is virtually always a House Finch—they seem to specialize in this particular nesting niche. So this spring, I’m going to set out baskets at my Ithaca apartment in hopes of attracting a nesting pair of these excellent birds. East, west, or right smack in the middle, House Finches are lovely and very welcome birds.