IN SEASON: Horned larks lead migration into the valley

Now that it stays light until after 6 p.m., it's time to start imagining when the birds will start showing up.

Birds are strongly phototropic. They respond to the length and strength of daylight.

That is why the swallows come back to Capistrano pretty close to the same day every year.

Though day length is a strong motivator for migrating birds, it is not the only factor that influences their arrival. Weather plays a role, too, and so does food supply.

The Capistrano swallows don't have to deal with weather conditions.

Birds returning to the Great Plains might be delayed by snow or cold. Snow keeps the fields covered, hiding the food supply for many birds, and cold keeps the wetlands frozen, discouraging waterfowl. Later, cold can push back the emergence of insects that so many birds species depend on.

These circumstances may slow the arrival of some species, and they may shorten the migration season so species arrive at the same time or closer together than they otherwise would.

The weather generally doesn't alter the order in which bird species return from winter quarters, though. This is pretty predictable because the birds follow a consistent pattern.

Horned larks are first.

Don't expect a horned lark in your backyard, though. They are open country birds. Strictly. And the more open the country the better as far as horned larks are concerned.

Horned larks could show up almost any day, and quite likely before the first of March.

Depending.

Bare ground crucial

The critical issue for horned larks is bare ground. They feed on spilled seed. If the seed is covered, the horned larks stay away.

Not far away, as it happens, however. Horned larks often spend the winter just west of the Red River Valley, where the weather is a bit less harsh.

They are regular winter residents on the ranchland Suezette and I own in Mountrail County, in northwest North Dakota. I've often seen them on winter afternoons foraging along south-facing hillsides. These slopes offer shelter from the wind and exposure to the warming rays of the sun.

In the valley, horned larks usually show up first along roadsides-sensible, since rural roads are generally cleared, and the sun melts ice and snow away from the road edge. What's more, lots of seed ends up there, both from roadside weeds and from passing trucks carrying grain.

Meadowlarks are early arrivals, too, often arriving by mid-March.

Despite the similar names, these birds are not closely related. Horned larks are true larks, the only native Americans among a large family of birds that occurs across Africa, Asia and Europe. Meadowlarks are blackbirds, an exclusively American family of birds.

Horned larks and meadowlarks share habitat, however, though meadowlarks demand more cover.

Both are signs of spring.

In towns, cities and farmyards, the American robin is regarded as a sign of spring. The robin isn't always reliable, though. Single robins, and even small flocks, sometimes spend the winter a here. This year, I had a single robin through January.

Groups of robins-that's a different story. It's spring when robins become abundant. And when they start singing.

Both eastern and mountain bluebirds are reliable signs of spring, as well. There's an old phrase about "bluebird weather," usually taken to mean fine weather. Bluebirds are early arrivals here, however, often showing up while the weather still is cold and blustery.

Waterfowl influx

The great waterfowl migration is next, commencing in mid-March and peaking by mid-April. Here the variable is open water. In recent years, large numbers of Canada geese have wintered on lagoons in the valley, so these geese, too, aren't completely reliable indicators that spring has actually arrived.

Big flocks of northbound snow geese, however, continue to announce the spring.

The raptors follow their own schedule. Northern harriers and American kestrels are usually the first, followed by larger birds of prey, such as red-tailed and Swainson's hawks.

Several species of blackbirds also are relatively early arrivals in our area. The males come first, and marshlands and reed beds will resound with blackbird music well before the female birds arrive.

Likewise, the vanguard of sparrow migrations begins by late March and builds quickly through April. Some species nest here, but many move farther north. Sparrows are seed eaters, so they, too, can survive bitter weather, as long as food is available.

Not so the warblers and the swallows. They are insect eaters, and so they depend on warmer weather.

The same is true of nighthawks, the latest returning nesters to arrive. They don't get here until mosquito season begins, usually after Memorial Day.