Many of you may have been fortunate enough to have at your feeders in the late fall and early winter any number of special winter visitors: irruptive finches or other birds whose breeding range extends across the vast Boreal Forest. In our neighborhood we were blessed with a large flock of pine siskins that spent weeks feeding in the tall northern white cedar on the edge of our neighbor’s driveway. We saw quite a large flock of common redpolls at the end of October over at the Viles Arboretum in Augusta. Mom Wells hosted some bright yellow evening grosbeaks at her Damariscotta feeder earlier in the fall, and our cousin’s husband photographed a migrating purple finch that landed on his boat 12 miles out to sea. And red-breasted nuthatches seem to be everywhere; they began to be detected in odd places as early as August as they started moving south in numbers.

In the same column in which we wrote about the boat-going finch, we wrote about the massive irruption of Boreal Forest-breeding birds, describing how these movements of large numbers of birds over vast distances do not happen every year. This is the case for most seasonal migrants. In fact, it is largely only birds of the Boreal Forest that seem to show these large-scale irruptions on a regular basis. This is, in part at least, because of the truly vast areas of intact habitat over which these species can breed during the summer. When there is a highly successful breeding season across the Boreal region, bird population numbers reach a high at the end of summer. If food in the Boreal then becomes scarce, then those huge numbers of birds begin moving south, looking for food—and providing us with lots of winter visitors to see.

We saw the largest numbers of some of the winter finch irruptive species—pine siskins, common redpolls, purple finches, and evening grosbeaks—in the late fall and early winter. Since then, we have seen only a few siskins and redpolls; other people have had similar experiences. Pine grosbeaks peaked later in our area—in December.

This got us wondering where those irruptive birds we saw earlier in the season are now. To answer that question, we queried the trusty eBird database (www.eBird .org).

It turns out that there are still scattered sightings of all of these species around Maine, including in our general area. But the total numbers seem to be less and the overall number of locations where they are being seen is lower. Perhaps the only species bucking that trend is the red-breasted nuthatch, which is still being seen at a great many backyard feeders across the state, even ones that don’t regularly host them, like ours.

There are some other interesting observations from eBird about these irruptive bird species. Just in the last few weeks, some have pushed farther south than they had been seen yet all year. In Florida, a purple finch was spotted as far south as the Sarasota area. Red-breasted nuthatches were found at Cape Canaveral, and a pine siskin was heard flying over Everglades National Park!

At the same time, pine siskins and red-breasted nuthatches were reported far, far to the north in the tiny community of Moosonee, on the shore of James Bay in northern Ontario. Red-breasted nuthatches are being seen this winter even farther north, in Yellowknife, Northwest Territories, where they are rare in winter. Perhaps most amazing of all, a red-breasted nuthatch was photographed in Iceland a few days ago—the second one ever recorded there! Based on the whereabouts of these birds this winter, who would have guessed? Or maybe better yet, who wouldn’t have?

Jeffrey V. Wells, Ph.D., is a Fellow of the Cornell Lab of Ornithology and Vice President of Boreal Conservation for National Audubon. Dr. Wells is one of the nation's leading bird experts and conservation biologists and author of the “Birder’s Conservation Handbook.” His grandfather, the late John Chase, was a columnist for the Boothbay Register for many years. Allison Childs Wells, formerly of the Cornell Lab of Ornithology, is a senior director at the Natural Resources Council of Maine, a nonprofit membership organization working statewide to protect the nature of Maine. Both are widely published natural history writers and are the authors of the popular books, “Maine’s Favorite Birds” (Tilbury House) and “Birds of Aruba, Bonaire, and Curaçao: A Site and Field Guide,” (Cornell University Press).