Spring is a month away, but more daylight has birds already courting

At first, the increase was hardly noticeable, with only 20 minutes gained through Feb. 1. But around mid-February, the increase in daylight became more rapid as we started getting two to three minutes more sunshine per day. By the end of this month, we will have gained more than an hour of daylight since the winter solstice.

The birds notice this. Photoreceptors in their tiny brains detect the increasing daylight, a key environmental cue that sparks a surge in breeding hormones. Higher hormone levels prompt the birds to begin courting, singing and establishing territories to attract mates.

Some birds go to great lengths to woo a mate. One of the most elaborate rituals is that of the American woodcock, a plump, brown, long-billed, ground-nesting bird of moist woodlands and brushy shrublands in Georgia’s Piedmont and coastal plain.

Around this time of year, woodcocks perform their “sky dance” in open fields at dawn and dusk. Males make nasal “peent” calls on the ground, then spiral up to 300 feet, making whistling sounds with their wings. Then, while emitting twittering sounds, they zigzag and flutter back down to the ground to impress females.

No less impressive is the acrobatic courtship of red-tailed hawks at this time of year.

Their routine consists of dramatic aerial displays, including high-altitude soaring and synchronized steep dives. Notably, pairs of hawks interlock their talons while spiraling together toward the ground. Red-shouldered hawks perform similar routines.

More earthbound are the courting habits of great blue herons, whose complex mating “dances” involve exaggerated strutting, neck stretching, feather ruffling, bill snapping and twig exchanging.

Pairs of American crows, which often mate for life, also are strengthening their bonds with aerial displays, bowing and dancing. Eastern screech owl males are whinnying, trilling, nodding, bobbing, winking, raising wings and clicking bills to attract females and establish territories.

Mourning dove courtship right now features dramatic, noisy aerial displays by males, followed by bowing, head-bobbing and mutual preening. Less noisy but no less interesting are the rituals of male Northern cardinals and blue jays, which insert seeds into mouths of potential female mates — perhaps the males’ way of showing that they can provide for a family.

But you have to go no farther than your yard to hear love-smitten birds now. Song sparrows, pine warblers, bluebirds, Carolina wrens, tufted titmice, Carolina chickadees and others — most of them silent since late fall — are replacing winter twittering with genuine, complex singing.

Male cardinals already are singing their spring “what cheer” songs, often in duets with females. Woodpeckers have begun their mating season and announcing their territories by vigorously drumming on houses, telephone poles and other structures.

By the time spring arrives March 21, most of these year-round birds will be nesting; some will even have babies. As spring progresses, even more daylight will spur even more singing and nesting as migratory birds arrive from winter grounds in Latin America.

IN THE SKY: From David Dundee, retired Tellus Science Museum astronomer: The moon will be first quarter Tuesday and full March 3. Mercury is low in the west just after dark; by early March, it will be in the east just before dawn. Venus remains in the west just after sunset. Saturn, now low in the southwest at sunset, will go out of sight by Feb. 28. Jupiter is in the east through next week but will be high in the south in early March.

Charles Seabrook can be reached at charles.seabrook@yahoo.com.