A male northern cardinal (Cardinalis cardinalis) sings from his springtime perch.

I like the silence of frosty mornings, but I also miss the music of birds during the winter. Most mornings for the past three weeks, our resident cardinal has greeted the sunrise — cloudy or clear — with song. At first he sang one short burst of bright song. Over the next week, it grew to several minutes of song at dawn and another round later in the morning. Basking in Tuesday’s sunshine and 70°, he sang many times during the day. Later that same day, a mourning dove cooed in a spruce tree, chickadees added their lovely two-note calls, and an American robin joined the serenade with its caroling. However, all went silent when a Cooper’s hawk sailed across the backyard and into my neighbor’s silver maple!

Why do birds sing more frequently in the spring? There’s still much to learn, but the thinking is that the increase in daylight triggers a bird’s thyroid-stimulating hormone (TSH). TSH steps up the production of sex hormones to prepare birds for the mating season. A big part of successful reproduction is attracting a mate and maintaining a breeding territory — birdsong plays a major role in both activities.

The four songsters mentioned above were year-round residents in the Twin Cities this past winter.  Soon migrants, such as warblers, red-winged blackbirds, catbirds and others will return to add their harmony to the chorus. In fact, I saw my first red-winged blackbird of the season perched on a cattail in a small pond yesterday. Regardless of its purpose, the return of beautiful birdsong is one of spring’s finest gifts.