The house finch is a rather ubiquitous song bird that can be found throughout the United States (including Hawaii) as well as parts of Mexico and Canada. Very commonly found at backyard feeders, the bird is sometimes referred to as the linnet (though related, this is technically incorrect).
They belong to the Order Passeriformes (Latin passer, meaning "sparrow") which is the largest Order of Aves, encompassing over half of all extent species. These are the perching birds. Sometimes put into the Sub-Order Oscines (Latin oscinis or "singing bird"). Unsurprisingly, the house finch is part of the Family Fringillidae (Latin fringilla meaning "chaffinch") which includes all the finches as well as many related seed-eating species (there is some debate over inclusion of some species under Fringillidae). The species is Carpodacus mexicanus (fruit biter from Mexico).
Last year two house finches built a nest in our backdoor awning. It was underneath and they could be seen from the door. Not recognizing many bird species other than the obvious zoo types and typical Midwestern robins, blue jays, cardinals, and those god damn crows that are big enough that they look like they could carry away a small pet, I looked for them in guides at the bookstore and online. The splash of red on the breast was the clue I needed.
The house finch is about 5½ inches (13.9 cm) long. Both male and female have brown wings with some darker streaking, but there they diverge somewhat. The female has some white on her underparts and brown streaks, particularly on her head (in a pattern not dissimilar to the sparrow). While the female is a plainish brown for the most part (common in nature in order for a more noticeable male to distract predators), the male has bright, often red (though sometimes, shades of yellow and orange) breast feathers as well as part of the head and "posterior." The color is the most obvious identifying mark of the species and comes from carotenoid pigments in the seeds that the bird eats.
Though the house finch will occasionally eat insects, "vegetable matter," and sometimes fruit (as suggested by its name), the main source of food comes from various seeds (young are also fed with seeds). The bird has a conical beak which is common in avian species prone to eating seeds and grains. Part of the success of their spread across the US has been because of the abundance of available seeds in backyard bird feeders where they have become a common sight over the years. Sunflower seeds are a favorite.
Like our own little pets. Not sure how much the face at the backdoor window was appreciated. Or the porch light turning on in the middle of the night—especially after the babies (I called them "fuzzy heads") were born. I just wanted to make sure they were okay. Every time the door opened or you pulled into the driveway, they'd dart away from the nest and sit in the neighbor's tree chirping what had to be their displeasure. Four eggs were laid and four babies born.
As can be guessed from the species name, the original range was Northern Mexico and the Southwestern US, up into California and a few other western states. Successful at adaptation, the bird more than likely would have continued to spread with available sources of food and pressure from population density. A more direct cause of its vastly increased range is due to numbers that were caught and taken to the East Coast during the early part of the twentieth century. Thought to have come from the Los Angeles area, many of these birds made their way to New York City where they were being sold as "Hollywood Finches."
The birds had been taken illegally from the wild (a violation of the Migratory Bird Treaty Act of 1918 and subsequent legislation) and dealers, wishing to avoid prosecution released the birds into the wild in 1943. They were soon seen regularly in Long Island and continued to fan out, reaching North Carolina by 1963.
By the 1970s, house finch sightings were reported in Indiana and continued westward. Today the species covers almost the whole continental US and into Southern Canada, as well as having been introduced into the Hawaiian Islands. In 2000, there was an estimated population (continental US and Canada) ranging from 268 million to 1.4 billion house finches (the numbers may be dropping, see below). The bird does migrate but not over large distances like many other migratory birds.
But panic began—it seemed the parents had abandoned the nest (maybe too many nightly checks and intrusive peeking from behind the blinds). It'd been a few days and no sign of them. I was worried for my little friends. I took an eyedropper that had been given by a veterinarian to dispense medicine to a dying hamster. I'd drag a wooden chair out to the cement porch and try giving them water. It was a hot humid Midwest summer. The cool water was probably appreciated. The nightly checks became more frequent. Fortunately the parents "returned."
In March or April (location may vary the date somewhat) the female builds the nest made of available material, dried stems being very common. While conifers are a popular site (as well as other trees), true to its remarkable adaptability, the house finch will build its nest in the words of one source in "any cavity or projection on a building which is capable of holding a nest" (home.bluemarble.net). They have been found in hanging planters and even the abandoned nests of other birds. Nests are sometimes reused in successive years.
The eggs are laid within a week or two; usually two to six. The female builds the nest and does the incubating, while the male brings her food (I believe I've seen the male incubating on occasion). The incubation period usually lasts from twelve to fifteen days. The nestlings are born naked-looking with eyes closed. Shortly after, the female takes the eggshell away from the nest. They shortly begin to grow filament-like hairs, not getting the beginning of true feather development until the third day and not growing a near full set of plumage until almost a week.
The young stay in the nest for about two weeks before they make their first flight, after which they usually do not return. the average life expectancy (as best as can be estimated from banding studies) is about ten years.
I found the first body on a Saturday afternoon. It was lying on the cement where it had fallen from the nest. Startled, I put off my plans until I could get out the shovel and bury the little bird behind the garage near the hamsters. It left a heartbreaking wet spot where its head had landed. It took weeks before I couldn't see it. Later that day, I drove past a deer that had been hit by a car. Everything was dying that Saturday.
House finches generally have little to fear from predators because of their predilection for living near humans and their backyards (yet another factor in the species' success). Unfortunately for the birds, the last decade of the twentieth century brought with it a previously unencountered disease: House Finch Conjunctivitis or Mycoplasmal Conjunctivitis—named for the parasitic bacterium (M. gallisepticum) which had previously only been known to affect poultry.
It was first noticed in the Virginia and Maryland area in 1993-1994 and has rapidly spread from there. By 2000 it had spread from as far north as Canada, to southern Florida and as far west as Nebraska. It is highly possible it is even more widespread. The actual disease is a respiratory infection, but the disease itself doesn't kill the birds, a particular symptom does.
The eyes become red and swollen, often leading to crusting over and partial or total blindness. Because of the crusting, the bird is unable to fly, tend to its young, and feed itself adequately (more often than not, they die from starvation). What predators there are can more easily capture them, as well.
The second one died in the nest. I suspected for a few days but tried not to believe it. The other birds didn't seem to notice. It was the one that hadn't been interested in the eyedropper. When the birds finally vacated the nest, mom took it down and started to wash out the mess that had been left behind. I rescued the nest from the garbage and buried it and its tiny, abandoned, desiccated occupant behind the garage next to its nestmate and the hamsters.
While the disease has not been found to spread to humans, other birds have been found with the disease (all from the family Fringillidae). Some things that help the disease are the large population that sometimes forages in flocks, the fact that the eastern birds started from a smaller gene pool and are more inbred than more genetically diverse western house finches, and survival (which by itself increases possible infection of others) does not confer immunity from reoccurrence. While bird feeders have not been implicated (for certain) in facilitating the spread, the possibility remains and people asked to periodically wash them out with a solution of one part bleach to nine parts water.
While it is estimated that as many as five to ten percent of eastern house finches have the disease, not all is bleak. In the birds' favor is the huge initial population and what seems to be a leveling off in the speed of the disease's spread. House finch populations are not a "extreme risk" at this time but the disease is serious and not to be taken lightly. It seems that after the local populations were first hit, a steep drop in number occurred, followed by a stabilization at somewhat lower levels—something that is encouraging.
It's spring and the birds are returning. I suppose they'll find a better place to nest this year.
(Sources: lupus.northern.edu:90/natsource/BIRDS/Housef1.htm, www.wbu.com/chipperwoods/photos/housefinch.htm, home.bluemarble.net/~pqn/ch41-50/houfinch.html, seattletimes.nwsource/news/health-science/html98/s1gene06m_20000606.html, members.aol.com/FinchMG/Home.htm, birds.cornell.edu/hofi)