The house finch (Haemorhous mexicanus) is a small songbird native to western North America. Originally only found in the southwest United States and Mexico, house finches were introduced to the eastern United States in the 1940s and their range expanded rapidly. For decades, house finch populations thrived across North America. However, in recent years there are indications that house finch numbers may be declining in parts of their range.
What are house finches?
House finches are small-bodied finches with a domed head and short, conical bill. Males have bright red plumage on their heads, breasts, and rumps. This red coloration is derived from carotenoid pigments in their diet. Females and juveniles are brown-streaked overall with a pale belly.
House finches measure 14–18 cm in length and weigh between 21–26 grams. They have a wingspan of 20–25 cm.
What is their native range?
House finches are native to the western half of North America. Their native range stretches from southern Canada to Oaxaca in southeastern Mexico.
In their native habitat, house finches occupy a variety of open and semi-open areas including deserts, shrublands, farmland, suburbs, and parks. They avoid dense forest.
How were they introduced to eastern North America?
House finches were first introduced to the eastern United States in 1940. A small number of wild-caught birds from California were sold as “Hollywood finches” in pet shops on Long Island, New York. The finches were released or escaped into the wild and began breeding.
This introduced population expanded rapidly. By 1970 house finches had spread through the Mid-Atlantic states and up to New England. Through the 1970s to 1990s, they continued spreading westward and southward across eastern North America. Along the way, more small introductions from the pet trade supplemented their numbers.
When did they become established across North America?
By the year 2000, house finches had successfully colonized almost all available habitat across North America. Their range encompassed over 6 million square kilometers. The rapid expansion was driven by multiple introductions combined with the finches’ adaptability to human-altered environments.
Today, house finches are abundant year-round residents across most of the United States and southern Canada. Their range extends north to Alberta, east to Nova Scotia, and south to Florida and Mexico. One of the most widely distributed native birds on the continent.
Why are populations thought to be declining now?
After becoming so widespread and numerous, house finch populations are now believed to be declining in certain areas. However, exact rates and causes of decline are not well understood.
Some of the evidence that house finch numbers may be dropping includes:
– Christmas Bird Count data shows declining trends in the Northeast since the 2000s.
– Breeding Bird Survey results indicate declines in Western states like California and the Southwest since the 1980s.
– House finches were historically very common urban and suburban birds but now seem less abundant in many cities.
– Declines observed on migration monitoring stations across the Great Lakes region.
More research is needed to confirm the declines and determine if they are short-term fluctuations or long-term trends. But the convergence of data suggests house finches may have passed their peak abundance.
What factors could contribute to declining populations?
If house finch declines are confirmed, what could be behind them? A few potential contributing factors:
Disease
A major house finch decline was observed following a 1995 outbreak of mycoplasmal conjunctivitis, a bacterial disease. This epidemic severely reduced eastern populations. Western birds may now be impacted by the same disease.
Competition with other species
Other finch species like purple finches may compete with house finches for food and nest sites. Some have theorized purple finches have displaced house finches in eastern habitats.
Predation
Increased predation pressure from resurgent Cooper’s hawk populations may play a role in house finch declines.
Reduced food availability
House finches rely on seeds from native plants and backyard bird feeders. Declines in natural food sources and changes in feeding habits may negatively impact finches.
Year | Northeast | Southeast | Midwest | West |
---|---|---|---|---|
2000 | 500,000 | 400,000 | 600,000 | 700,000 |
2005 | 450,000 | 425,000 | 575,000 | 650,000 |
2010 | 400,000 | 410,000 | 540,000 | 600,000 |
2015 | 375,000 | 400,000 | 500,000 | 550,000 |
2020 | 350,000 | 375,000 | 475,000 | 500,000 |
Table shows house finch population estimates by region from 2000-2020
This table uses fictional data to demonstrate one potential trend of declining house finch populations in each region since 2000. This illustrates the reported widespread declines, though true rates likely vary across different areas.
What can be done to help house finches?
If house finch declines are substantiated, conservation efforts will be needed to study the causes and stabilize populations. Some actions that could help house finches include:
– Monitoring populations long-term through surveys like the Breeding Bird Survey. This allows tracking regional trends.
– Banding birds to study survival rates and movement patterns. Banding reveals demographic information.
– Maintaining habitats with native vegetation that provides seeds and nesting sites. This ensures food availability.
– Limiting pesticide use which reduces food sources and causes physiological harm.
– Providing clean bird feeders and baths, especially in winter when natural food is scarce. This supplements their diet.
– Nest boxes can boost nesting sites in appropriate habitat. Predator guards help protect against threats.
– Public education campaigns can encourage bird-friendly practices to support finches.
Conclusion
House finches rapidly colonized North America over the past century and became one of the continent’s most recognizable backyard birds. However, emerging data suggests their populations may now be declining in certain regions. The causes are likely complex. While more research is needed, proactive conservation measures such as habitat management and supplemental feeding could help ensure house finches remain a vibrant part of the avian community. Their bright songs and colors would be missed if this familiar finch were to fade away. With thoughtful action, hopefully the house finch’s long-term outlook can be a positive one.