THe WiLson BuLteTIN—No. 75. 
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known fact that light-houses are quite destructive to birds on 
their migrations, it is not so well known that only a very 
small percentage of the birds that pass such lights ever strike 
them, while the number that are killed is even smaller. My 
observations confirm those of other observers in that the birds 
seemed to strike the light only under certain conditions. Dur- 
ing my eight weeks stay on the island I found dead birds on 
but two occasions, althcugh I saw birds fly around and past 
the light in great numbers nearly every night. As a rule, the 
weather was fine and the nights clear with the wind generally 
north or south, and birds do not generally strike the light 
under these conditions. 
One of the most notable bird waves occurred on the night 
of September 4, when I noticed numbers of small birds flying 
past the light soon after it was lighted (which was always 
at sundown). The night was cool and cloudy and there was 
a light north wind. The birds came from due west and con- 
tinued to increase in numbers until midnight, when a severe 
thunder storm came up from the northeast accompanied by 
strong wind and driving rain. This with the darkness seemed 
to confuse the birds, which came to the light in great num- 
bers. From the west side of the platform which surrounds the 
light, I watched the migration until the storm was over, and 
at daylight the birds stopped flying. The wind and the rain 
did not seem to stop the migration and dozens of birds were 
in sight all of the time. Most of them came from the south- 
west and flew directly against the wind, which no doubt had 
forced them to the south of their line of flight while over the 
water. Most of them flew very slowly, and as they entered 
my vision they looked like drifting leaves, and, as they neared 
the light they went over, below, and all around it. A few 
fluttered against the glass and I caught several in my hands. 
A very few struck the glass with a dull thud, which I could 
hear even when on the other side of the light. Some of them 
fell dead on the platform, others bounded off to the ground. 
The majority of the birds that struck were only stunned and 
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