. Bird-lore . ij^.:-: . ,— FLICKER AT NEST-HOLE The same site had been used for two previous seasons, in one of which thewas artificially enlarged by some boy Photographed from nature bj A. L. Princehorn, at Glen Island, N. Y., June 16. 1899 The Birds that Pass in the Night. BY HARRY S. WARREN PON the request of ]\Ir. H. A. Winkenwerder, ofthe University of Wisconsin, I made arrangementsto take observations with the telescope at Detroitupon nocturnal bird migration, using the moon for a fieldof vision, during the full moon in May. The moon wouldbe at full at eight a. m. on the 14th, INIonday,
. Bird-lore . ij^.:-: . ,— FLICKER AT NEST-HOLE The same site had been used for two previous seasons, in one of which thewas artificially enlarged by some boy Photographed from nature bj A. L. Princehorn, at Glen Island, N. Y., June 16. 1899 The Birds that Pass in the Night. BY HARRY S. WARREN PON the request of ]\Ir. H. A. Winkenwerder, ofthe University of Wisconsin, I made arrangementsto take observations with the telescope at Detroitupon nocturnal bird migration, using the moon for a fieldof vision, during the full moon in May. The moon wouldbe at full at eight a. m. on the 14th, INIonday, but,anticipating cloudy weather, we made our observations onSunday evening, the 13th, which was clear and warm,with a very light southwest wind. As it was rather late in themigrating season, we expected poor results, but a glance at thetabulated figures below will show that we were pleasantl} disap-pointed. There were four principal facts we wished to establish by theseobservations: the number of birds, the direction of flight, theirspeed, and relative size. In order to obtain this data we numberedthe four cardinal points on the field of vision, and for every birdthat passed we wrote down, on blanks prepared for the purpose,the point or fraction of a point at which h
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Keywords: ., boo, bookcentury1800, bookdecade1890, booksubjectbirdsperiodicals
