10 Fun Facts about the House Finch

House Finches are currently among the most widespread and common birds across the United States—but as we'll see, that wasn't always the case. These days, they can be found brightening backyards and chowing down at seed feeders from the arid Southwest to the humid cities of the Northeast. Familiar as they are, there’s plenty about these cosmopolitan birds worthy of closer attention and deeper appreciation. 

1.) Once limited to the Western United States and Mexico, House Finches are now found from coast to coast, and as far north as southern Canada. In 1939 a few of the birds, originally captured in Santa Barbara, California, were set free on New York’s Long Island by a pet store owner. By the early 1940s wild nests were beginning to show up on Long Island, and from there the spread continued. They’ve also been introduced and become widespread in Hawaii. In some places, House Finches are considered an invasive species. They act as a vector for disease and compete for food and territory against native birds like Purple Finches—a species they’re sometimes confused with since males share reddish plumage. 

2.) In their native range, House Finches live in desert, grassland, shrubland, and open woodland environments, as well as near human dwellings and cities. This pre-existing penchant for urban areas likely helped them thrive when they were introduced to new areas. The biggest House Finch flocks in the East are found in cities, and it’s much more common to find the eastern birds in habitats developed by people than anywhere else. 

3.) House Finches can look very different depending on where they live. The birds come in 11 officially recognized subspecies. Body and bill size, shape, wing length, tail length, and coloring can all vary regionally. For instance, on Guadalupe Island off the coast of Baja California, Mexico, the finches have heftier bills than those found on the mainland. And eastern finches have longer and pointier wings than their western counterparts. That distinct wing shape is better suited to long flights, scientists say—a helpful trait for more northern House Finch populations in the East, some of which migrate south, while western finches tend to stay put year-round.

4.) There are even local House Finch accents. In California, the standard male’s song lasts for two seconds and contains between 4 and 26 syllables. In Wisconsin and Colorado, studies have shown that songs last longer and contain more syllables. In New York State, distinct dialects abound, with males’ songs noticeably differing within just one square mile.

5.) Although House Finches are well adapted to dry climates, they still need a lot of water. On especially hot days, they can consume more than their own bodyweight in fluids. Luckily, succulent plants abound in their native, arid habitat, offering a hydrating food source. Eating the fruits and flowers of cacti, such as saguaros and ocotillo, allows the finches to get enough liquids without drinking directly. Still, they love water as much as any other species, and a birdbath is likely to draw lots of them to your yard.

6.) A western House Finch is likely to build its nest within 60 feet of where it was the previous breeding season, while its eastern counterparts have been known to choose sites more than half a mile away from prior nests. Within that home turf, they may choose any variety of settings including coniferous trees, cactuses, planters, streetlights, and windowsills. However, almost all House Finch nest sites have a couple of things in common: a sturdy base and a roof-like overhang to shelter against sun and rain.

7.) The reddish-orange (and sometimes yellow) plumage that mature House Finch males sport on their crown, throat, and chest comes from compounds in their food. These pigments, known as carotenoids, are the same ones found in carrots and tomatoes. Female finches prefer males with bigger and brighter red patches—it’s a sign of a well-fed mate!

8.) House Finches are among the strictest avian vegetarians: Seeds, buds, fruit, and foliage comprise 97 percent of their year-round diet. Most seed-eating birds switch it up in the spring and summer when insects become abundant, but House Finches rarely do. The biggest exception is that parent finches will feed their nestlings soft and squishy fly larvae as an early life protein boost.

9.) The species has been dealing with its own pandemic for decades. House Finch eye disease, a form of conjunctivitis, was first detected in Washington D.C. in the winter of 1994. Since then, the bacterial illness has expanded continent-wide and caused big declines in House Finch numbers. Infected birds often have swollen or reddened eyes and may appear inactive or confused. Over time, it leads to birds becoming blind, disoriented, and vulnerable to predators. Other finch species, such as the American Goldfinch, are also affected. The disease is spread through social contact, so keeping your bird feeders and baths clean is important.

10.) Their plant-based diets might suggest peace-loving passivity, but House Finches can be very aggressive, especially at feeders. In fact, they’re so territorial around food and nest sites that they’re one of the only birds known to fight off non-native House Sparrows. Where House Finch populations go up, House Sparrow numbers drop.