Birds

adult laughing gull
A breeding plumage adult laughing gull with charcteristic black head, blood red bill, dark gray mantle, and white eye-crescents attained during the breeding season. These medium-sized gulls nest on nearby islands, including Muskeget and Mini-Moy, both to the east in Nantucket Sound. After their young fledge, they feed up in local waters during the fall, and then head south to the Gulf coast for the winter. Photo by E. Vernon Laux

Post-breeding molt regimen

By E. Vernon Laux - July 19, 2007

This past week was a summer stunner, absolutely gorgeous and a perfect time to be on vacation. While the birding is not red hot now, it is steadily improving. This is a time of change in the natural world and the fall bird migration is underway. Shorebirds, (a.k.a. waders) sandpipers and plovers, are on the move. These hemisphere-crossing birds are appearing in considerable numbers on beaches and tidal flats, while local land birds are still finishing the breeding season.

While human residents and visitors are reveling in the balmy weather and enjoying the beaches in midsummer, the wild bird has a different agenda. For songbirds such as Carolina wrens, mockingbirds, or American robins the breeding season is starting to wind down. These species often raise more than one family a season and may have up to three clutches in a season. The feisty wrens seem to be very successful this year and reports of fledgling wrens are widespread.

For all the single-brooded species like vireos, warblers, and most sparrows, the hard work of raising young has ended. Defending a territory is now a waste of time, so the level of bird song has dropped markedly. Now the birds must undertake a full molt, replacing their feathers in preparation for the upcoming migration and winter.

This requires lots of energy. Fortunately food is plentiful at this season and birds are able to meet the increased energy requirements. Birds are recovering from the rigors of feeding voracious young and now tending to their individual needs. Birds are dependent on their feathers and must take time to groom and oil them. But now they must grow new ones and this (like most moments in the wild) is a critical time.

For globetrotting shorebirds that visit our area for a week or two, this is an important stopover. The shorebirds are all adults. They have evolved an incredible migratory schedule and breeding system.

They left their precocial young alone on the tundra only a few days to weeks after they hatched. Unlike baby birds in nests in our area, shorebirds are born fully feathered and are up and running around shortly after hatching. The adults never feed them; they are on their own. Because of the abundance of insect life for a brief time in June and July in the 24 daylight of the tundra, there is plenty of food for the ravenous and fast developing young.

The adults then gather in small flocks and depart south to known feeding areas. The birds' powers of navigation and flight defy description and the same birds generally return to exactly the same place, at nearly the same time, year after year. (If it's not broken don't fix it.)

The shorebird migration has two distinct peaks in our area. First is the passage of the adult birds, peaking near the end of this month, and then near the end of August or early September comes the second peak comprised mostly of young birds. These first-time migrants, flying many thousands of miles by some innate genetically passed-on navigation system, are essentially flying blind. Their migration is marvelous, mysterious, and incredibly athletic.

Bad weather-grounded shorebirds

The best time to find large numbers of shorebirds is during and immediately after stormy weather with precipitation. The unsettled weather of the past few days has provided perfect conditions to optimize birding opportunities on the Vineyard. This causes these strong flying birds to divert from their normal routes that would carry them east of or over the Vineyard without stopping. Fast-moving frontal systems, thunderstorms, and heavy rains create a dangerous and serious threat to the birds' survival if they fly into them. Encountering such conditions causes survival mode to kick in and the birds change their somewhat flexible flight plan.

This heavy weather tends to stop birds flying south over the ocean essentially forcing them to ground. Often the flats on the Vineyard will have impressive numbers of birds during and just after thunderstorms or the like. But as soon as the weather clears, they get up and go - they have a schedule to keep.

Checking the flats on a daily basis is a great pastime whether you're vacationing on the Island or you live here permanently. The only constant thing on the flats at this season is change. Daily, with the passing of every tide, a new experience is afforded, often with completely different birds. Often the same species mix is present that was present the day before but in entirely different numbers and concentrations.

The more often one checks the flats, the more one finds and sees. Rarities and vagrants often appear briefly on the flats before continuing on their respective "fly-about." One has to be there to see them or they don't get seen. If you don't go birding you won't see any birds. Ditto for fishing: if you don't go fishing you won't catch any fish.

Until next week - keep your eyes to the sky!

To contribute news about birding activities or sightings, call The Times Birdline, 508-693-6100, extension 33, or e-mail vernlaux@comcast.net.