The results of this year’s Christmas Bird Count have demonstrated population trends and borne out birders’ expectations on species’ range increases.

One bird that has been extending its range into more northerly areas each year is the tufted titmouse. This sparrow-sized bird with the incongruous name resided mainly along the Mississippi and Ohio river basins at the turn of the century. Data from the Christmas counts alerted ornithologists of their expansion, and by 1970 the birds had reached Maine.

The tufted titmouse resembles a cardinal in appearance and song. However, instead of bright red, the titmouse’s upper parts are gray from the top of its crested head to the tip of its tail. Its underparts are a creamy to buff white, bordered by rusty flanks. It has a little black patch on its forehead.

Its primary song is a clear, loudly whistled “peter, peter,” which resembles one of the cardinal’s calls, and may be sung throughout the year. It is a special treat to hear this exuberant trill in the winter, as I did some weeks ago in Veazie. I immediately thought of it as a promise of spring’s return, as it lightened my heart and conjured up images of warm, breezy days.

I was able to observe four tufted titmice at my feeder recently. I was first alerted to their presence by their song, which I could hear even though windows were closed against winter’s chill. They are robust birds, stockier and larger than chickadees. These characteristics enabled them to displace the smaller birds at the feeder, thereby giving them first pick of the sunflower seeds. It was comical to see how boldly the titmice flew at the chickadees, which then beat a hasty retreat.

The four birds that I observed were most likely a mated pair with their young from last summer’s brood, since families stay together through late winter. The pair may have raised more than one brood, in which case juveniles from the first clutch would have remained to help their parents raise the second. Young can be distinguished from adults by the absence of the black forehead.

There are four species of titmice that include the United States in most or part of their range. The tufted, or northern, titmouse occupies the largest area of the continent. A different population known as the black-crested titmouse occupies central Texas and Mexico.

There are also juniper, oak, and bridled titmice, which are primarily southwestern birds. All belong to the same family, Paridae, which includes the chickadees. Other species also occur in Eurasia and Africa.

The availability of tree cavities for nesting is a conservation issue for these birds. In the absence of nest boxes, the removal of suitable deadwood affects their breeding success, as it does other cavity-nesting birds.

Thanks to ornithologist Frank Chapman, who in 1900 called for an end to the indiscriminate slaughter of wildlife occurring at that time, the Christmas Bird Count was created to count birds, rather than kill them. The result has given us an invaluable tool for discovering their lives.

Results for the Bangor/Bucksport CBC – as yet unofficial – documented a total of 61 species seen. Highlights were common loons spotted on the still-open water of Brewer Lake, six raptors (such as two rough-legged hawks and an osprey), Bonaparte’s, glaucous and Iceland gulls, and a Carolina wren.

Chris Corio’s column on birds is published each Saturday. Corio, a volunteer at Fields Pond Nature Center in Holden, can be reached at fieldspond@juno.com