. The bird book. Birds. kind and the same age always have the same colored eyes. Often this makes an easy way to tell one species from another. The red-eyed vireo and the white - eyed vireo conld easily be distin- guished by the color of the eye alone. So, too, the common towhee of the North with his red eye is readily distin- guished from the white-eyed towhee of the South, which otherwise is almost precisely similar. But here we find a curious fact. The white-eyed towhee is not a distinct spe- cies, but is a race of the red-eyed, and we find that part way between the northern and the souther
. The bird book. Birds. kind and the same age always have the same colored eyes. Often this makes an easy way to tell one species from another. The red-eyed vireo and the white - eyed vireo conld easily be distin- guished by the color of the eye alone. So, too, the common towhee of the North with his red eye is readily distin- guished from the white-eyed towhee of the South, which otherwise is almost precisely similar. But here we find a curious fact. The white-eyed towhee is not a distinct spe- cies, but is a race of the red-eyed, and we find that part way between the northern and the southern limits of the two forms, — in Geor- gia, for example,—the towhees are neither Fig. 37. — Head of white-eyed nor red-eyed, but have brownish ^^o^^n^^^(^^^^)' eyes. A curious in- stance of seasonal change has been observed in the Louisiana egret. In the spring, during nesting time, both the male and female have a red eye, surrounded by bare blue skin. In the female the iris gradually changes to yellow after the breeding season is over, while the blue skin becomes yellow also. The male keeps „ „„ „ •^ ^ Fig. 38.— Head of Goos= his red eye. ander (Female).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Eckstorm, Fannie Hardy, 1865-1946. Boston, Heath
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Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbirds, bookyear1901
