The House Finch has not always been found in the eastern United States. In 1940, they were illegally captured in California and imported to New York by pet dealers. Fearing prosecution, the dealers released their “Hollywood Finches” on Long Island in 1940. Since then the finches have spread to all corners of the east and have even rejoined their relatives in the west.
The eastern population of House Finches has developed a consistent annual and often long-range migration pattern, while the native western population is primarily residential, occasionally migrating only short distances. Many House Finches from the Northeast U.S. and Great Lakes regions migrate to the southern U.S. to spend the winter.
In the East, female House Fiches migrate farther south than do the males. Southern states often find a majority of brown females at their feeders, while northerners enjoy more of the colorful red males.
House Finch populations found in the east are rarely found far from urban or suburban areas, but in its native western range they may also be found in a wide variety of open or semi-open habitats including undisturbed deserts.
Male House Finches display a wide variety of plumage coloration ranging from gray to bright crimson. The coloration comes from carotenoid pigments found in some wild foods. The more pigment present in the foods eaten when they are molting new feathers … the redder the male.
Female house finches prefer to mate with the reddest males they can find.
House Finches were introduced on the Hawaiian Islands sometime before 1870. Known there as the papaya bird, after its favorite island food, males lack the red color of mainland birds as papaya has no red pigments.
House Finches roost at night in close proximity to each other, sometimes huddling together for warmth. Favorite roosting spots are used repeatedly.
House Finches are fond of nectar and can become a nuisance at hummingbird feeders, if they do, offer them a dish of nectar for their own use.
A water source can be a strong attractant for House Finches. They can drink up to 40% of their body weight on a hot summer day.
House Finches are almost strictly vegetarian feeders and approximately 97% of their diet is made up of vegetable matter including buds, seeds, and fruits. They are strongly attracted to feeders, where they prefer small sunflower seeds.
House Finches’ diets are the most vegetarian of any North American bird. Unlike most other seed eating birds, finches do not switch to an insect diet during the summer nesting season. They continue to eat mostly seeds, although they will prey on some insects when they are abundant.
House Finches are highly attracted to sodium salt and will seek out sources of it to eat.
House finches differ from purple finches by the male purple finch's purple side streaks (unlike the brown streaks in a house finch) and by the female's conspicuous eye stripe (female house finches lack this feature).
The Eastern population of the House Finch has decreased by almost 50% in the last 10 years due to an eye disease known as avian conjunctivitis.
Studies have shown that when the avian conjunctivitis enters a new area, it takes three years before the population of House Finches stabilizes at about half of the pre-disease level. It is theorized that transmission of avian conjunctivitis between House Finches is dependant on high density populations.
It is thought that since the entire Eastern population of the House Finch is the progeny of a small number of birds liberated on Long Island, New York in 1940, their low genetic diversity may make them more susceptible to the avian conjunctivitis disease than other bird species.
It was once believed that the rapid increase of the eastern House Finch population was responsible for a decline in the number of House Sparrows. Recent research shows that that the two population trends are unrelated.
Banding studies show House Finches may live to be over 11 years old in the wild.
House finches are early nesters, beginning in March in most of the country.
Both male and female House Finch display a strong tendency to return to the same area to breed, often occupying the same nest site as the previous year.
Male House Finches do not defend a defined territory very far away from their nest; instead they concentrate on defending the area immediately surrounding their mate. They will chase and fight another male when it gets too close to their female partner.
Ironically, House Finches rarely use bird houses to build their nest in; instead they seem to prefer locations such as: coniferous trees, cactus plants, ledges, street lamps, ivy on building and hanging planters.
House Finch typically produce at least two broods each nesting season. Research has shown that some individuals may attempt to nest up to six times per year, but only half of the attempts were successful in fledging young.
A few female House Finches have been observed laying their second clutch of eggs several days before fledging their young from a previous brood. This is possible due to the male predominant role in raising the young from the earlier nest.