With the end of winter, birders begin to clean out bird feeders and change the type of food, as spring species begin arriving. They may also be brushing out and closing up birdhouses for bluebirds, tree swallows and wrens, or putting up new ones. But it’s not just birders who prepare for spring. Birds, too, ready themselves for the change of seasons.
The change in birds that is most noticeable is the migration of a large proportion of them. In winter, a backyard feeder will be lucky to attract five or 10 different species. In spring, the variety of birds can increase dramatically, especially if a late snowfall results in the birds halting their migration for a time.
Usually the earliest arrival, in late February or early March, is the horned lark. As March passes, eagles and crows appear in increasing numbers, and honking geese fly overhead. (The first crow used to be a welcome sign of spring. Now, with their frequent overwintering in cities and towns, a crow isn’t so much a spring sign.) With April most years (perhaps sooner this year) come robins, meadowlarks, bluebirds, grackles and blackbirds, and by May we watch for orioles, a variety of warblers and thrushes, and ruby-throated hummingbirds.
Moulting is another important change for many birds. Adult birds shed their worn feathers for fresh ones, while last year’s juveniles moult into their first adult plumage. In many species, this results in brighter colours, particularly for the males. This is very noticeable with the American goldfinch. Goldfinches in winter are a dull beige colour with black wings, white wing-bars and just a touch of gold — often not even recognized as goldfinches. The change of the males to their late-spring and summer bright yellow and black is amazing. The common redpoll, which may frequent feeders in winter, also changes as the males’ chests become a much brighter rosy pink. Even birds such as the blue jay are noticeably more vibrant.
Behaviour is also different. Birds which migrate in flocks, such as robins, begin to disperse into pairs or singles. Overwintering birds which may have flocked in winter, such as waxwings, also disperse. Some species become increasingly aggressive as they compete for territory or mates or available food.
Diets may change too. As insects and nectar become available, some species which live on seeds all winter change to occasionally feasting on insects.
Birds in spring become more vocal, chirping or singing loudly, perhaps even waking us before dawn. Others, such as the ovenbird (a type of warbler), may sing at night, while a variety of owls begin calling at night as early as March or late February. The chickadee changes its song to a three-note whistle, instead of the more recognizable “chickadee, dee, dee, dee.”
One spring activity of various woodpeckers, sapsuckers and flickers may be less acceptable to us, as they often drill their bills against wooden or metal parts of houses, as a means of attracting a mate or claiming territory. Another type of territorial drumming, heard in forests and most often in spring, is that of the ruffed grouse. Some species of birds seek to attract mates in other ways. Sandhill cranes may dance as part of a courtship ritual. Bald eagles sometimes practise a spring ritual in which both fly to a high altitude, lock feet and tumble almost to the ground before releasing. Many other species, as diverse as crows, chickadees and hawks, practise courtship feeding.
With some birds, nest building starts even before they pair up. The male house wren, for instance, may begin to stuff nest boxes with twigs, perhaps to impress the female or to stake his claim to a territory. They may load up a variety of other cavities, too, such as old boots left on a shelf, or farm machinery sitting outside or in a shed. Many years ago my family found the sleeve of a shirt stuffed with twigs after it was left hanging out on a line overnight.
All of these activities are a sign that birds, like people, change with the seasons. So, if you’ve put away your bird books over the winter, it’s time to get them out!