I know winter is coming to an end.

Snow and ice may still linger, and temperatures may still be well below freezing. But, for the past week or so now, I’ve heard a northern cardinal singing every morning with the rising of the sun. It didn’t matter how cold it was, he still sang.

Also recently, I looked up as I was shoveling snow and was amazed at the enormous flock of robins passing overhead. It was an impressive sight: waves upon waves of robins rolling by against a wild, blustery, cloud-tattered sky.

I wasn’t the only one to notice them; the Maine-birding e-mail list contained numerous reports of such sightings, as well as large numbers of bohemian waxwings.

The cardinal didn’t surprise me; these birds have been expanding their ranges steadily northward over the last several decades and are year-round residents here. They might become less conspicuous in the heart of winter and range farther in search of food, but for the most part they are nonmigratory.

I was a bit surprised by the number of robins I saw that day. Many people consider them to be among the first signs of spring, and this is generally true. However, some populations of robins may only travel a short distance beyond their breeding ranges, depending upon the availability of food. According to “The Birds of North America” species account, some robins – such as those in Newfoundland – may “find winter resources in forested slopes and valleys near their breeding sites.”

I found it interesting that the flocks of robins being reported so frequently as of late have been noted to be quite dark in color. According to taxonomists, there exists seven subspecies of robin; each can be distinguished from the other based on such characteristics as size, wing shape, and plumage variations. Birds from breeding populations in Newfoundland are generally noted for having a darker-hued plumage.

The question remains: Were these robins already making their way back north, or were they leaving their northern “forested slopes and valleys,” because food resources had been depleted? There is no way to tell for sure.

As I had mentioned several weeks ago, this winter we’ve seen a large irruption of many bird species due to widespread seed, cone, and fruit crop failures across Canada. No surprise we’d see large numbers of bohemian waxwings, as these birds are well-known for ranging far from their breeding territories in search of food. In winter, this consists of the sugary fruit of cherry trees, apple and crabapple trees, mountain ash, hollies and mulberries.

These usual and not-so-usual sightings have surely been magnified and multiplied this past weekend during the annual Great Backyard Bird Count, a joint “citizen science” project sponsored by National Audubon and the Cornell Lab of Ornithology.

It’s always a treat to learn of participants’ discoveries, misses and near misses during the count. I recall reading someone’s query about whether she actually saw a winter wren. This small woodland sprite of a bird is migratory; we don’t usually see them back here until April. But I’m inclined to believe it; years ago, I found a wren making itself at home in a horse barn weeks ahead of when it was “officially” supposed to be here.

That’s the beauty of this hobby: You just never know. The mystery keeps us coming back for more.

For more information about the Great Backyard Bird Count, preliminary reports and statistics for this year, please visit: www.birdsource.org/gbbc/.

bdnsports@bangordailynews.net