House finches are some of the most numerous birds at my feeder right now, always there in cheery little groups of bright red males and subtly brown-streaked females. They are fun to take photos of because they are relatively slow-moving, staying put as they crack open the black oil sunflower seeds at my feeder. They also are friendly with humans. Unlike the blue jays that are such raucous busy-bodies but disappear the minute I step outside, house finches don’t seem to mind me lurking around taking photos,

House finches are a recent arrival to the eastern North America. They were originally found only in the western U.S. and Mexico (hence the scientific name Haemorhous mexicanus). In the 1930s house finches (the bright red males in particular) were being trapped and sold as "Hollywood Finches." They made appealing caged birds with their bright colors, friendly demeanor and lovely bubbling call. However, trapping wild birds was (and is) illegal under the Migratory Bird Treaty Act of 1918 and so, to escape prosecution, a Brooklyn pet shop released a few in 1940. It's easy to guess what happened next. A couple were spotted at Jones Beach that year. Within 50 years they had spread across the United States and southern Canada, even to Hawaii. In their original range they occupied a variety of habitat types - from desert to grasslands to semi-open forests. Here in the east they generally live near humans, in fact they benefit from human presence (they really love our feeders, even the hustle and bustle of city life).

Their current numbers are estimated to be somewhere between 267 million and 1.4 billion. That’s a lot! They are at least as numerous as (actually their numbers probably exceed) starlings, robins, and mourning doves. Interestingly, unlike introduced species such as starlings and house sparrows, which are vilified as unwanted invasives, people usually welcome house finches - most likely because they are cute and friendly.

The biology behind the bright red color of the males is fascinating. According to the Cornell Lab of Ornithology: “The red of a male House Finch comes from pigments contained in its food during molt (birds can’t make bright red or yellow colors directly). So the more pigment in the food, the redder the male. This is why people sometimes see orange or yellowish male House Finches. Females prefer to mate with the reddest male they can find, perhaps raising the chances they get a capable mate who can do his part in feeding the nestlings.” Except for Hawaii where there are almost no red male house finches.

If you haven’t seen a house finch, check out any bird feeder. You will likely see a few, or many. They are very social and are almost never seen alone (except during breeding season) and can form huge flocks. If you have a feeder and want to participate in some citizen science and join Project FeederWatch. The organization is tracking house finch eye disease, a type of conjunctivitis that causes red, swollen, crusty eyes and respiratory problems making the victims more susceptible to predators and poor weather. This led to a steep decline in the house finch population beginning in 1994 (when the condition was first noticed at bird feeders in Washington D.C. area). By joining Project FeederWatch (www.birds.cornell.edu/citscitoolkit/projects/clo/housefinchdisease) you can help researchers study the occurance and spread of this disease in the United States and Canada. Now that they are here it would be a shame to see them go.

Susan Pike, a researcher and an environmental sciences and biology teacher at St. Thomas Aquinas High School, welcomes your ideas for future column topics. She may be reached at spike3116@gmail.com. Read more of her Nature News columns online.