Purple Finches are regular if erratic visitors to our feeders.  The gorgeous males with their deep red breasts and heads can only be confused with male House Finches.  A male House Finch has brown streakings on the flanks with less extensive red (more reddish-orange) on its head.

Female Purple Finches are mostly brown and white.  The breast has dark streaks.  A bold white stripe lies just above the eye; this white supercilium is absent in female House Finches.

Have you noticed that male Purple Finches are usually outnumbered by females at your feeder?  Not so fast.  First-year males are dead ringers for female Purple Finches. You really have to have them in hand to tell them apart by examining the wear of the primary coverts and the shape of the tips of the outer tail feathers.  Some of those streaked Purple Finches at your feeder are first-year males.

Purple Finches belong to the suite of irruptive finches  popularly called the northern finches.  Purple Finches breed across the northern tier of the U.S. from Maine to Minnesota  and across the southern tier of the Canadian provinces.  A breeding population also occurs west of the Cascades and Sierra Nevada from California to British Columbia.

Strong southerly irruptions occur every other year in this species.  These biennial irruptions are thought to be driven by variation in the production of cone crops of the conifers on which the Purple Finches depend.

To gain some insight into these movements of Purple Finches, my wife Bets Brown and I analyzed all of the banding data on Purple Finches from the Bird Banding Laboratory over the period of 1921 until 2008.  Over 745,000 finches were banded over this period and almost 20,000 of those banded birds were subsequently recaptured (or in a few cases, found dead).

We were particularly interested in three questions.   During irruptions, do birds from one area like New England move straight south or do they spread across the continent (Purple Finches can be found throughout North America)? Do Purple Finches show fidelity to breeding sites?  Do Purple Finches show fidelity to wintering sites?

The analysis of banding data presents many challenges.  Banding effort is never constant either across space or time.  Most of the banding records come from the period 1960-1985.  Banding effort varies greatly among states and provinces.  Nevertheless, some general patterns can be discerned.

Birds banded in VT, NH and ME were re-encountered broadly but mostly in the eastern United States, curling eastward through the Gulf Coast states.  A few reached Texas and modest numbers occurred in MI, ONT, WI and MN.  A similar pattern emerged for birds originally banded in NY.

We also analyzed birds first banded in PA, NJ and NC.  These areas are south of the breeding range and were banded in the winter.  Re-encounters of these birds occurred mostly in the the New England and the eastern provinces.  The re-encounters are consistent with the data from birds originally banded in New England.

Moving to to the Midwest, birds originally banded in MI, WI and MN also were re-encountered broadly but most irruptions were due south.

Only 275 Purple Finches banded in the Pacific states or BC were re-encountered.  However, a consistent pattern was that those birds migrate west of the Cascades and Sierra Nevada.

We did find some evidence of breeding site fidelity across as many as five years.  Some wintering site fidelity was evident as well over periods of one to six years.  Uneven banding efforts prevent us from knowing how prevalent such fidelity is.

I’ll end with the most impressive distance between captures. A Purple Finch banded in Maine in 1966 was subsequently captured two years later in Texas, a distance of 1792 miles.

For a copy of our paper, visit http://bit.ly/1BntjMb

[Original published on March 29, 2015]