Sunday, April 10, 2011

Electrosmog and the Bicknell's Thrush in the Franconia Range

This post draws upon the research and writing of Tim and Janet Williams, Swarthmore College emerti who live in the White Mountains and oppose Northern Pass as proposed. Thanks to Tim and Janet for reviewing a draft of this post.

Bicknell's Thrush, a species of high conservation concern

They've begun to arrive again--those brightly-colored song birds that winter from southern Florida to South America. And high on the list of "how do they do that?" is the question of how our New Hampshire migratory birds navigate their way thousands of miles to and from the neotropics every year. The answers have started to come in. Research has established that some birds navigate by means of “magnetoreception." Robins, for example, have an extraordinary ability literally to see the earth’s magnetic fields and thereby orient north and south for biennial migration. First detected in 1968, the mechanism is not fully understood yet, but some birds have visual receptors in the retina of the right eye that allow them to see these fields and to use them as markers, signposts pointing north and south, for migration. Other birds, such as pigeons, have magnetite in their beaks that may function as a kind of internal compass. As the research on magnetoreception expands, so does the concern among ornithologists, biologists, and others that the EMF “electrosmog” caused by proliferating wireless devices, cell towers, and transmission lines may affect avian navigation during migration.

Within a few miles from the proposed HVDC power line in the WMNF are two major bird migration pathways, according to research on autumnal routes by Timothy C. Williams, Janet M. Williams, and others. (See “Bird Migration through a Mountain Pass Studied with High Resolution Radar, Ceilometers and Census,” The Auk 118(2), 2001: 389-403). One pathway runs north to south over the mountains of Franconia Notch, and the second runs northeast to southwest along the face of the Franconia Range following the line formed by Lafayette, Cannon and Kinsman mountains.

In their scoping comment, the Williamses write that this area of the White Mountains appears to be a crossroads of migration. Birds concentrate along these two routes especially on nights of heavy migration and use both routes simultaneously. As the proposed HVDC power line cuts across the Easton Valley, rises to 2500’ to crest the Kinsman Ridge, and then drops down into Woodstock, it crosses these migratory highways. The Williamses estimate that about 11,000 birds cross each kilometer of migratory front per hour during heavy migration. Thus, on a single night, about 3.5 million birds would cross the proposed power line route at low altitude which would be a 40 KM distance passing through the western White Mountains. Since migratory birds are known to use magnetic fields for orientation, the Williamses continue, the proposed Northern Pass HVDC power line could disorient them, altering their long distance flights both north and south.

Of especial concern is the Bicknell's Thrush, a species of high conservation importance that biologists estimate now numbers only between 20,000 to 50,000. This neotropical bird breeds almost exclusively at higher altitudes, at or above 4000', in sub-alpine spruce-fir forests of the northeastern U.S. and a few Canadian provinces. In NH, the elusive Bicknell's Thrush is found in Presidential range mountains, including Washington, where birders on Auto Road tours listen for its call and hope to catch sight of it. In the Franconia range, it may be seen just below the summit of Cannon Mountain on the south and west sides and on Mount Lafayette between Greenleaf Hut and timberline, locations within a few miles of the proposed HVDC line. This vulnerable species could be affected by electromagnetic interference during premigratory flights, the Williamses conclude. (The Eagle Cliffs on the west side of Lafayette have a peregrine falcon aerie as well.) 

When augmented by the proposed additional HVDC line within the 150’ WMNF special use corridor, the EMF radiation from the current HVAC line could produce a disorienting electrosmog that has long term consequences on the animal world, including species already in decline like the Bicknell's Thrush that migrate through Franconia Notch. We in New Hampshire have the extraordinary privilege of hosting this rare and vulnerable bird as well as the responsibility not to contribute further to its decline by siting the potential threat of an unneeded and unrequested merchant transmission line in its documented migratory pathway. Just as physicians and major health organizations recommend prudent avoidance of schools and other places where humans congregate when siting high voltage transmission lines, so this precautionary principle should guide our actions as stewards of the animal kingdom. We know we've made too many mistakes already. Please keep this in mind as you hear our brightly-colored annual guests announce their arrival this spring.

Bicknell's Thrush summer breeding range