THE MIGRATION OF NORTH AMERICAN BIRDS 57 
once seen from the deck of a vessel in the Gulf of Mexico, 30 miles 
off the mouth of the Mississippi River. Great numbers of migrating 
birds, chiefly warblers, had accomplished nearly 95 percent of their 
long flight and were nearing land when, caught by a norther, against 
which they were unable to contend, hundreds were forced into the 
waters of the Gulf and drowned. On another occasion, on Lake 
Michigan, a severe storm, coming up at a time when large numbers of 
migratory birds were crossing, forced numerous victims into the waves. 
During the fall migration of 1906, when thousands of birds were cross- 
ing Lake Huron, a sudden drop in temperature, accompanied by a 
heavy snowfall, resulted in the death of incredible numbers. 
Literally thousands were forced into the water and subsequently cast 
up along the beaches, where in places their bodies were piled in wind- 
rows. On one section of the beach the dead birds were estimated at 
1,000 per mile, and at another point at five times that number. Most 
of them were species that rank among our most desirable birds as 
destroyers of insects and weed seeds, including slate-colored juncos, 
tree sparrows, white-throated sparrows, swamp sparrows, winter 
wrens, and golden-crowned kinglets, together with many brown 
creepers, hermit thrushes, warblers, vireos, and others. 
Of all species of North American birds, the Lapland longspur 
(Calcarius lapponicus) seems to be the most frequent victim of mass 
destruction from storms. These birds sometimes congregate in 
enormous numbers where grass or weed seed is abundant. Almost 
every winter brings in reports of their death by thousands somewhere 
in the Middle West. While migrating northward at night they have 
encountered blinding storms of wet, clinging snow, which have so 
bewildered them that they have flown into various obstructions, or 
have sunk to the ground and perished of exposure and exhaustion. 
In 1907 an experienced ornithologist estimated that 750,000 longspurs 
were lying dead on the ice of two lakes in Minnesota, each about 1 
square mile in extent, and dead birds were reported in greater or less 
abundance on this occasion over an area of more than 1,500 square 
miles. The heaviest mortality occurred in towns, where, bewildered 
by the darkness and the heavy falling snow, some of the birds con- 
eregating in great numbers, flew against various obstacles and were 
killed or stunned, while many others fell to the ground exhausted. 
Similar catastrophes have been reported from eastern Colorado, 
Nebraska, and North Dakota. 
During the early part of June 1927, a hailstorm of exceptional 
severity in and around Denver, Colo., killed large numbers of robins, 
meadow larks, sparrows, and others. The lawns of parks were strewn 
with the bodies of these birds, and many lay dead in their nests where 
they were covering their eggs or young when the storm broke. 
AERIAL OBSTRUCTIONS 
The destruction of migratory birds by their striking lighthouses, 
light ships, tall bridge piers, monuments, and other obstructions has 
been tremendous. Beams of the lanterns at light stations have a 
powerful attraction for nocturnal travelers of the air. It may be 
likened to the fascination for lights that is shown by many insects, 
particularly night-flying moths. The attraction is not so potent in 
clear weather, but when the atmosphere is moisture laden, as in a 
heavy fog, the rays have a dazzling effect that lures the birds to their 
