Published January 03, 2010, 12:00 AM

ALWAYS IN SEASON: Goldfinches now stay here during winter

The emergence of American goldfinches as regular winter birds is one of the big local stories of the decade in the bird world. Twenty years ago, goldfinches would have been unusual in winter.

By: Mike Jacobs, Grand Forks Herald

The more American goldfinches I see, the more I am impressed with this plucky species.

A swarm of goldfinches has been coming to the feeders at my place west of Gilby, N.D., for several weeks. About 40 were there most of New Year’s Day.

Goldfinches were seen on all of the local Christmas bird counts this year.

The American goldfinch is one of the iconic birds of summer in our region. The males display brilliant summer plumage, a spectacular combination of yellow with black wings accented by white wing bars. There’s also a black patch on the top of the head.

This plumage disappears by early winter, however. Winter goldfinches are much plainer birds, rather greenish yellow tending to gray. But the white wing bars are constant and help distinguish goldfinches from other plain-colored birds of winter.

The emergence of goldfinches as regular winter birds is one of the big local stories of the decade in the bird world. Twenty years ago, goldfinches would have been unusual in winter.

It’s because of the climate, some observers would say, but that’s a tough argument to make when there’s close to 2 feet of snow on the ground, and the thermometer is stuck below zero.

Still, goldfinches in winter might signal something that we humans, so attuned to the immediate, have not noticed. Other species once absent, or at least unusual, have become regular here, and now can be expected in winter. Among these are the northern cardinal and red-bellied woodpecker, both once unknown in the northern Red River Valley.

But the changes in bird population aren’t conclusive evidence of global warming. Other factors may have led some species to move into the area, or to stick around to spend winter in places where they were once only summer birds. Chief among these are habitat changes and changes in the availability of food.

In the first category, place the growing forestation of our part of the continent. Grand Forks has become a kind of urban forest, albeit one with large clearings and great expanses of pavement. And farm shelterbelts are commonplace.

Especially notable is the maturation of evergreen plantations. The Red River Valley was pretty much an evergreen-free zone only a few decades ago. But evergreens planted as ornamentals in cities and towns and as shelterbelts in rural areas have matured and now provide shelter for a variety of species.

American crows have proliferated here at least partly because they find shelter in evergreens. Crossbills have become regular winter birds, and occasional nesters, because evergreen cones provide a source of food.

Goldfinches are open country birds not often encountered in forest environments — so something else must be responsible for the explosion in goldfinch populations.

The likely answer is sunflowers, for two reasons. Sunflowers have become a common field crop in the last several decades, and sunflower fields supply food for goldfinches. This is especially true in years when winter comes early and sunflowers are left standing unharvested in the fields.

Sunflower have another impact.

Humans provide sunflowers.

And goldfinches eat sunflower seed.

The swarm in my backyard is evidence of that.

The truth is that goldfinches have been almost the only birds at my feeders. Now and then, a chickadee appears. Or a white-breasted nuthatch. Both downy and hairy woodpeckers have been coming to suet.

Such frequent winter visitors as pine siskins and common redpolls have been notably absent, though. This underscores the nomadic nature of these birds, which appear in large numbers some years and are close to absent in others.

The relative absence of northern birds probably also reflects this winter’s weather patterns. Last week’s big storm came out of the south — and may have discouraged birds that might normally move south.

A chickadee provided good entertainment this week for my partner, Suezette. The bird struggled to pick up a peanut that she’d put out in the hope — futile as it turned out — of attracting blue jays during last week’s storm.

The peanut was a challenge for the chickadee, and the bird soon turned its attention to a smaller nut and managed to pick this one up.

But even a small peanut proved too much for such a small bird as a chickadee, and the bird tipped sideways with its load. Probably pecking at the peanut provided some nutrition for the chickadee, however, and so the story may have a happy ending.

Jacobs is publisher and editor of the Herald. This column appears Sundays on the Outdoor page.