Page:The Zoologist, 4th series, vol 4 (1900).djvu/279

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The lowest figures obtained for the same quill-feather were: — It will be noticed from the foregoing figures that, as far as difference of sex is concerned, there is a marked excess of length for this longest of the flight-feathers in both the old and the young individual male birds over the females of from 7 to 14 mm. We thus find Dr. Butler's conclusions fully confirmed when confining ourselves to this feather exclusively, but if the same test be applied to a considerable number of individuals we not only get every degree of length possible for this quill amongst the two sexes, but as a matter of fact the same individual variation manifests itself in all the other flight-feathers. For this longest one, then, we get a range from a maximum of 219 mm. to a minimum of 200 mm. for adult males; the latter being smaller by 5 mm. to female individuals, both old and young, which is that of 205 mm.
 * For an adult male||219 mm.
 * For a juvenile male || 212„
 * For an adult female || 205„
 * For a juvenile female || 205„
 * }
 * For a juvenile female || 205„
 * }
 * }

If the relative lengths range for the adult males between 219 to 200, for the young males from 212 to 200, they do the same in the case of the females, which for the adults is one of from 205 to 190, and one of 205 to 192 in young females.

A reproduction of the table of measurements of all the twenty flight-feathers in the wings of these twenty-seven birds would serve no useful purpose, as may be gleaned from the following example, applying to the first specimen composing the list of birds measured: —

Sum total, 2889. Formula for index, $2889⁄20 (remiges)$ = index, 144·4.