Bird song quiets as migration begins

While the songs of summer birds are on the wane, many birds are already on the move. By early September, millions of migratory songbirds and shorebirds will fill the skies.

The Arctic tern has the longest migration of all birds and animals. It traverses 22,000 miles, circumnavigating the Atlantic from the Arctic to the Antarctic and back.

And shorebirds, as a group, undertake some of the longest migrations of North American birds. Nearly two-thirds of shorebird species journey from their Arctic breeding grounds to winter in Central and South America, and back again in spring, traversing nearly 15,000 miles in the round trip.

But shorebirds, unlike the V-flight formations of swans and geese that fly over Vashon October through December, aren’t often seen in migration. They fly fast (up to 50 miles per hour), high (10,000 feet and higher) and at night to avoid both predators and overheating in their marathon flight segments, which approach 2,000 miles within 48 hours.

This feat is even more astonishing for the fledglings. They are left behind to fatten up and put on a full set of flight feathers before taking their own leap of instinct into the skies, two to three weeks after their parents.

Now just imagine leaving your kids behind on a remote Aleutian island after a summer cruise, waving goodbye and saying, “See you in Buenos Aires!”

How do they make it? Many don’t. Although southbound adults may stray off course, they make corrections to arrive at their regular wintering sites. The inexperienced young are less able to do this. But the young birds have an instinctive magnetic compass and possess some ability to reckon by the sun and stars.

Those that complete their first journey have refined their celestial maps and learned to recognize mountains and rivers as landmarks for staying on course in repeat trips. There’s nothing like experience.

The largest number of shorebirds migrating through Washington stop to rest and feed at invertebrate-rich mudflats on the coast. Still, significant numbers of shorebirds can be seen at favorable rest stops around the Northwest.

As early as July, Western sandpipers, members of the group of small and similar-looking shorebirds called “peeps,” drop in to rest and feed at Fern Cove and KVI. This local peep enjoys a more modest migration as it winters across a wide swath of the more southerly coastal United States to Central America.

In September they are joined by other peeps, plovers and less common shorebirds that drop in to rest and feed here.

Similarly, many songbirds, including tanagers, grosbeaks, warblers, flycatchers and others also leave before their fledglings to winter mostly in the southern United States to Central America. Male Rufous hummingbirds follow the blossoming of flowers up into the mountains in July and take a southerly track through Western subalpine zones to Mexico, followed in August by females and then juveniles.

As you get to know the lives of birds, you’ll notice how quiet it is by September. Watch and listen for brief episodes of amorous behavior and occasional bird song as the shorter days and cooler temperatures mimic spring mating conditions. Such episodes are captured in this excerpt from Susan Stile’s poem (title same as closing line):

“What’s the reason for their warbling? Why on earth this late splurge. The autumnal recrudescence of the amatory urge!”

Yet as the autumn quietness deepens, you might wonder — are there any birds left? Absolutely! Nearly a third of the 240 species seen here are year-round residents. But even the residents become more cryptic and sing only simpler, single-syllable contact and warning calls.

The vocal portion of the song sparrow brain atrophies for the winter to conserve weight. But the bird retains sufficient neural capacity for a simple contact and warning call, “jimp…jimp…jimp,” heard throughout Island brush and thickets in winter.

As the last migratory songbirds take flight, you may still hear the nightly screeches of the many resident juvenile great horned owls learning to hunt for themselves.

And you may notice the waters around Vashon gradually come alive again with returning loons, grebes and many different species of colorful bay, sea and pond ducks. Did you notice their absence in summer?

— Alan Huggins teaches classes and leads field trips for Vashon Audubon.

Enjoy birds

Do you wonder what that beautiful bird was outside your window? Which owl was it that you heard last night? Where are the best places to see birds on Vashon-Maury Island? Answer your questions about birds at the Enjoyment of Birds classes offered by Vashon Audubon.

There is an introductory session and a Gardening for Birds tour for beginners, and a series of six additional sessions for budding birders. Classes begin Wednesday, Sept. 9, and continue monthly on second Wednesdays, from 7 to 9 p.m. at the Land Trust Building.

The beginners’ class is $20 and the complete series of seven sessions is $70 for Audubon members. Download registration information at vashonaudubon.org or e-mail Alan Huggins at alanhugs@comcast.net for more information.

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