because they are walking on firm ground where muscular exertion and an
exercise of judgment are necessary at every step; whereas birds floating
buoyantly and with little effort through the air are quickly bewildered.
Incredible numbers of migratory birds kill them-selves by dashing
against the windows of lighthouses; on bright moonlight nights the
voyagers are comparatively safe; but during dark cloudy weather the
slaughter is very great; over six hundred birds were killed by striking
a lighthouse in Central America in a single night. On insects the effect
is the same as on the higher animals: on the ground they are attracted
by the light, but keep, like wolves and tigers, at a safe distance from
it; when rushing through the air and unable to keep their eyes from it
they fly into it, or else revolve about it, until, coming too close,
their wings are singed.

I find that when I am on horseback, going at a swinging gallop, a bright
light affects me far more powerfully than when I am trudging along on
foot. A person mounted on a bicycle and speeding over a level plain on a
dark night, with nothing to guide him except the idea of the direction
in his mind, would be to some extent in the position of the migratory
bird. An exceptionally brilliant ignis fatuus flying before him would
affect him as the gleam of a lamp placed high above the surface affects
the migrants: he would not be able to keep his eyes from it, but would
quickly lose the sense of direction, and probably end his career much as
the bird does, by breaking his machine and perhaps his bones against
some unseen obstruction in the way.