A nightly stroll puts walkers in midst of migration
The Standard Speaker, standardspeaker.com 21 August 2011
The Standard Speaker, standardspeaker.com 21 August 2011
I have been enlivened many times by these sounds – the tiny, articulate but still-audible calls, trills, chirps and even snatches of territorial-like songs – voiced by migrating songbirds passing far overhead after dark. And all of it is sound (sounds of wild nature), not human noise as in lawn mower, leaf blower, chain saw, etc.
I heard them again last night – here in northwestern Vermont, from which I am now writing. The occasion was hardly a dedicated bird walk (up at dawn to catch the morning choruses, then breakfast), but a simple post-dusk walk with my Shetland sheepdog Kestrel along for the company. She’s used to it and so am I. A stiff 10-minute walk helps us sleep later.
At 9:30 p.m. (that’s 2130 hours to former military people, of which I am one), the first calls were clear to my ears. The conditions were much improved from 12 hours previous when an overnight rainstorm was finishing its appointed job, soon to be pushed to the east by the passage of a stiff cold front.
Migrating songbirds, many of which travel by night to keep cool and avoid predators, were passing high overhead on their autumn journey. With patience, and perhaps a bit of luck, I will hear them again tonight, especially since there’s a favorable northwesterly wind blowing at a the moment, perfect tailwind for a southbound migrant.
Why fly at night, not by day? It’s a matter of energy and calories. Drop to terra firma with dawn – most preferably in natural habitat, and then begin searching for and eating in order to fatten up for the next night’s push southward. Migratory songbirds – and even bigger avian masters of flight like snow geese and Canada geese and sandhill cranes and bald eagles and many more are adept at doing this same chore – heed their stomach (not the tee vee and video game console as many humans do) when it calls.
Just how far are many of these nighttime migrants traveling before reaching their winter homes? The Magnolia warbler, a breeding species of the northern tier of Pennsylvania and on up into the Adirondacks and Canada, has, like many species, a veritable marathon.
The Cornell Lab of Ornithology, on its “All About Birds” website, offers these descriptive words for the bird that many birders call “Maggie”:
“Though it has very specific habitat preferences in the breeding season, the Magnolia warbler occupies a very broad range of habitats in winter: from sea level to 1,500 meters elevation, and most landscape types, except cleared fields. The name of the species was coined in 1810 by Alexander Wilson, who collected a specimen from a magnolia tree in Mississippi. The male Magnolia warbler has two songs. The first song, issued in courtship and around the nest, consists of three short phrases with an accented ending. The second song, possibly issued in territory defense against other males, is similar to the first but is sweeter and less accented.”
The northward-in-spring and southward-in-fall journeys of birds, especially the smaller songbirds like the Maggie, are made even more remarkable by their seeming ability to dodge obstacles placed in their paths by, guess who, the human world. Had I dedicated myself to looking in the right spots, my logbooks of field notes recorded at the scenes of nighttime avian mortality would be much longer than they already are – and very depressing reading.
Some samples:
* The beautiful but quite dead wood thrush I found lying on a Broad Street sidewalk in downtown Hazleton one fall; its life extinguished after hitting a bank’s multistory building.
+ The American woodcock adorned with fresh spring plumage found dead in a Conyngham neighbor’s driveway, also killed by flying into the side of the building.
+ The red knot, a shorebird, found lifeless on one of the four rock-and-concrete islands on which the Chesapeake Bay Bridge-Tunnel passes between Delmarva and Virginia Beach.
+ The multiple – and quite dead – horned larks I found scattered about a taxiway on a now-closed Air Force base one early spring.
+ A search around the base of wind turbine towers one autumn morning turned up another grisly scene: dozens of dead gray catbirds, American robins, hermit thrushes and other species.
These and the other observations I recorded over the years don’t include the separate category of road-killed birds I once diligently recorded for posterity.
After reaching the mid-60s in number of species, I gave up that project as too depressing a matter for a dedicated conservationist – me – to be involved in any longer.
There are many scientific documents available to the public on the subject of the impact of man-made structures on migratory birds. With very little effort, I found one authored by John L. Trapp of the U.S. Fish and Wildlife Service’s Office of Migratory Bird Management in Virginia.
Trapp, in the introduction to his “Bird Kills at Towers and Other Manmade Structures,” wrote these words: “The purpose of this document is to increase public awareness of the potential impacts of towers and other human-made structures by highlighting some of the pertinent literature on the subject. The bibliography focuses primarily on collisions with communication towers, lighted buildings, and (to a lesser degree) windows. ”
While the toll is greatest, I suppose, when individual deaths are recorded as I once did over time, there have been many, and quite astounding, mortality events involving many thousands of birds at once. In one case, an estimated 5,000 to 10,000 longspurs were taken out of wild nature on Jan. 22, 1998, when a combination of fog, snow and radio transmission towers melded near Syracuse, Kan. The birds died when flung into guy wires around the towers.
Trapp notes many more such instances at www.fws.gov/migratorybirds/CurrentBirdIssues/Hazards/towers/tower.html.
It’s clear that what the bird world (which is our world, too, if only more people would remember that humans also are part of the great web of life) needs is a landscape on which there are at least fewer towering obstacles to dodge, fly over and around.
As for learning to identify birds by their sounds and calls and breeding-season territorial songs, there are many resources to help get you started.
I learned a lot early on as a budding birder just by listening a lot to singing birds and then turning on the CD player later. The Cornell Lab is again a good place to get started. Take a look at www.allaboutbirds.org/Page.aspx?pid=1059.
URL to article: https://www.wind-watch.org/news/2011/08/21/a-nightly-stroll-puts-walkers-in-midst-of-migration/