Kelly Barth, foreground, and Lisa Grossman bird-watch at the Baker Wetlands.

It baffled me how my next-door neighbor Dorothy could predict when the house wrens would return to our yards each spring. It seemed as if they called ahead to reserve one of the two houses hanging from each eave of her tiny white garage. She didn’t have a crystal ball or a Ph.D. in ornithology, either. The answer was simple: Dorothy had been keeping a notebook for the 40 years she’d lived in the house, and she’d noticed the wrens always came back April 18 or 19. She’d noticed. She taught me to do the same thing.

For instance, it isn’t spring until grackles return to the water pan around St. Patrick’s Day, heads thrown back, announcing their iridescent place in the world, hogging the seed. It isn’t summer until the swifts return to downtown Lawrence roosts for their evening tumbles into chimneys as if into so many vacuum sweepers. Birds make me aware of arduous seasonal patterns of movement above my head, rivers and balls of fellow beings that arrive and depart, moving about the planet in sync with the changes I sense around me — frost and thaw, humidity and cooling winds.

On one level, birds don’t need us; we need them. By simply hanging out a feeder, we can transform a gray-and-white winter world to blue, red and gold. Birds provide an easy way to interest children in the lives of fellow creatures. We can teach children responsibility and kindness by helping them fill and clean feeders, especially during extremes like our December blizzard. On another level, though certainly birds can survive without our help, we can mitigate human harm, such as habitat loss. Our feeders and fuel-rich plantings do create microhabitats that provide occasionally crucial fuel sources, especially for migrants, says Miyoko Chu, author of “Songbird Journeys.” “Even tiny pieces of nature are important for birds crossing fragmented landscapes.”

The advent of the Internet has made it possible for adult and child alike to take this interest in birds one step further by participating in any number of citizen science projects. One of these, the Great Backyard Bird Count (GBBC), is slated for Feb. 12-15. Each year, thousands of people across the United States spend as much time as they want counting birds and reporting the results to the GBBC sponsor, the Cornell Laboratory of Ornithology. Novice and expert birders alike can count from the comfort of their home or by taking a walk through their neighborhood, favorite park or wild area.

Like other such counts, the GBBC provides on-the-ground data that scientists literally could not access any other way. Whether you spot blue jays or yellow-rumped warblers, it doesn’t matter. All reported data contributes to the fuller picture of the abundance and distribution of populations across the country and can reveal early warning signs. With the health of even some common species such as the eastern meadowlark in peril, this is no small thing. Participation in the GBBC is free. All you need is interest, access to a computer and a little free time. The link is www.birdsource.org/gbbc.