Purple Finch

Winter Trend: Decreasing

Graph showing Purple Finch winter population trend in New Hampshire from 1987 to 2025, with model prediction and 95% confidence interval.

Purple Finch, 1987–2025.

The dark purple line shows the trend over time predicted by our statistical model, while the shaded purple area shows where we are 95% confident the true trend lies. Gray points are the number of Purple Finches actually observed in participants’ backyards, averaged per observer.

What’s the Story?

The Purple Finch, New Hampshire’s state bird, is an iconic species in our forests and backyards. Purple Finches are considered an irruptive species, meaning their winter numbers fluctuate depending on food supplies farther north. In years when food is abundant in Canada, few make their way south. Yet when food is scarce, large numbers may move into New Hampshire, feeding on conifer seeds and other available resources.

Our analysis of the Backyard Winter Bird Survey shows a troubling trend: a negative binomial regression reveals a significant downward trajectory (β = -0.057 ± 0.008 SE, z = -6.993, p < 0.001).

This translates to reports of Purple Finches decreasing by about 6% per year, even when accounting for changes in the number of Backyard Winter Bird Survey participants over time.

A similar decline has been seen in eBird Status and Trends data with a decline of 13.9% from 2012-2022 in New Hampshire. Interestingly, this same dataset shows an increase in other areas of their range including parts of Canada to our north  (see the map here). 

Purple Finches are often confused with the more common House Finch. Before House Finches expanded into the region, Purple Finches were widespread in New Hampshire. However, research suggests that competition with the non-native House Finch may be contributing to declines, with both species vying for food and nesting sites.

Climate change may pose an additional threat. Since New Hampshire lies at the southern edge of the Purple Finch’s breeding range, warming temperatures could further reduce suitable habitat for this species.

Feeding Tips

  • Purple Finches love black oil sunflower seeds and Nyjer. They will also readily eat sunflower chips and safflower.
  • Purple Finches visit a variety of feeders, from hanging tube feeders to platform feeders.

In Your Backyard

  • Purple Finches are far more common than House Finches north of the White Mountains. If you spot one south of the Whites—especially in high numbers—take a closer look, as it could be a House Finch.
  • While Purple Finches breed primarily in conifer forests, in winter they can be found in a range of habitats from backyards to forest edges.

ID Tips

Purple Finch on a bird feeder. Bright purple male.

Male Purple Finch by Len Medlock.

Male Purple Finches appear to have been “dipped in raspberry juice” with purple on the head and back. They also have less streaking on the back than the House Finch. Both sexes have a deeply notched tail.

Female Purple Finch perched at a bird feeder.

Female Purple Finch by Pam Hunt

Female Purple Finches are brown with a white stripe above the eye.

Look Alike Alert: House Finch

House Finches can be confused with Purple Finches. If you spot a Purple Finch south of the White Mountains, remember to take a closer look.

A male House Finch perched on a branch.

Male House Finch by Caitlin McMonagle, 2024 Backyard Winter Bird Survey.

Male House Finches are fire engine red on the head, breast, and rump. However, they have brown on much of their back. Both sexes have a more squared off tail.

House Finch perched on a branch, photo by Rebecca Scott, 2025 BWBS.

House Finch by Rebecca Scott, 2025 Backyard Winter Bird Survey.

Female House Finches are all brown.

Haemorhous purpureus

Understanding the Graph and Statistics

Observed Data (gray points):

The average number of birds counted per participant each year.

Model-Predicted Trend (dark purple line):

A line from a statistical model that estimates the overall trend in bird numbers over time, smoothing out year-to-year fluctuations.

95% Confidence Interval (shaded purple area):

The range around the predicted trend where we are 95% confident the true trend lies. Gray points inside this band indicate observations that are consistent with the predicted trend.

Other Stats You Might See in the Story:

  • β (slope) and SE (standard error): These numbers tell us how strongly and precisely the bird counts are changing each year.
  • p-value and z-value: These tell us whether the observed trend is statistically significant (i.e., very unlikely to be due to random chance). For example, a p-value less than 0.05 usually means a statistically significant trend in either direction.

The Takeaway: These graphs show how bird populations are changing over time. The model helps us see the overall trend and the confidence interval shows how certain we are about that trend.