Despite the recent trend of having strong nor'easters three weekends in a row, life in the natural world is keeping to a schedule. The longer days signal the impending greening of the landscape, and plants and animals alike are tuned in to a degree we cannot imagine. Life at this latitude is all about sunshine and the length of day.
The calendar delineates the start and finish of the seasons at a certain time on a specific day. In nature, timelines are not nearly so neatly defined. As this is being written, several species of birds — including a song sparrow, two northern cardinals, a Carolina wren and both downy and northern flicker, two species of woodpeckers — are singing persistently. It is 7:15 a.m., the temperature is 29 degrees with a light north wind and the sun is shining. It sounds like it is late April, not late February, outside.
The photoperiod — the amount of daylight, in other words — is rapidly increasing. Birds' endocrine systems respond to this and begin to produce hormones that prepare them for the rapidly approaching breeding season. While we are still huddling to stay warm, resident birds are already proclaiming their stakes to nesting territories.
The first land bird to return north in spring is invariably the red-winged blackbird. These hardy and extremely successful and adaptable birds nest in virtually every swamp, grassland and mixed successional habitat in the northern United States and southern Canada. Generally, migrants of this species return to the Cape and Islands during the third week of February.
The birds showed up this past week. Many reported hearing the birds singing and mentioned groups at feeders occasionally bursting into song. Nothing beats the winter doldrums like hearing the red-wings' cheerful song emanating from a still dreary winter landscape.
A small number of individuals of this species spend the winter on the Cape and Islands. This winter, more spent time in the region than ever. But the appearance of birds at far-flung locations is clear evidence of newly arrived birds from farther south. Presumably most of these early arriving birds are here, staging for the next leg of their journey and preparing to head for breeding areas well north of the Cape and Islands.
Also arriving are another hardy blackbird — common grackles. These large, iridescent, long-tailed birds seem to be returning north earlier every year.
Red-winged blackbirds used to return north a couple of weeks before grackles, but for the past five years the two species almost have coincided in their arrival dates in the region. A small number of this species also spent the winter, but several flocks have been seen and birds are showing up at locations where they were not seen all winter, indicating that these are migrants.
Male American goldfinches are visibly changing from their dull olive winter garb to the much brighter yellow that they sport during the breeding season. Many people call these small colorful birds wild canaries. They certainly look as though they belong in a more tropical setting. Feeder watchers from all over the area have noted this change in these common and frequent visitors.
All ducks are getting restless and can be seen displaying and courting. With the days growing longer, these very tough birds have thoughts of heading north to breeding areas devoid of trees. Imagine thinking of the winter waters surrounding the Cape as a winter paradise. That's the case for these birds of the far north. The waterproofing and insulating properties of their feathers boggle the mind.
It is interesting to note that males court the females, attempting to win their favor with stunning plumage and good display moves. Should the suitor be successful and beat out rival males, the pair head north along with others in flocks. As they get closer to breeding grounds, it is the male who follows the female to an area of her choosing for nesting. Generally, females return to the same (or exact) area where they were hatched.
The food required by the hundreds of thousands of sea ducks that spend the winter in Nantucket Sound and adjacent waters is staggering to ponder. Currently, these waters remain clean and productive, relatively free of pollution.
There is a sense of anticipation and expectancy in the natural world now, as the end of winter seems certain, just not quite at hand. Birds that are present are newly energized and exhibiting new behaviors. However, food — never abundant in winter — is scarcer still at this season. All birds are hungry; from fish-loving loons, to mussel-eating eiders, meat-eating red-tailed hawks, to seed-eating song sparrows. If you have been feeding birds all winter, don't stop now. This is the most critical time as birds' fat reserves have been depleted.
Spring is in the air in the form of bird song, but winter still clings to the thermometer. Change is evident all around.
Until next week — keep your eyes to the sky!
E. Vernon Laux's birding column appears every Saturday in the Cape Cod Times. Laux is the resident naturalist for the Linda Loring Nature Foundation on Nantucket. You can hear him on "Bird News" with Mindy Todd at 11 a.m. the first Saturday of the month on the Cape's NPR station, WCAI, 90.1, 91.1 and 94.3. You can also listen to his "Bird News Commentaries" on Wednesdays at 8:35 a.m. and 5:45 p.m. He can be reached at email@example.com.