Laboratory Bulletin Volume 1-14

Laboratory Bulletin Volume 1-14

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 edition. Excerpt: ...end of the first week in October. Grackles were found at the Oberlin roost from May 16 until the end of the second week in October--a difference of nearly four weeks between the two species. Mr. Brewster describes the woods occupied by the robins as a point toward which the host converged from all directions, singly or in small companies. The grackles approached their roost from one direction only, and arrived in larger or smaller flocks. The feeding habits of the robin are therefore different from those of the grackle Sometimes the robins were almost equalled in numbers by other species which shared the roost with them But the grackles far outnumbered all the other species seeking the protection of their roost. The fact that many rpbins rear two broods in a season and that the grackles rarely if ever rear more than one in this locality, would of necessity make some difference in the roosting habits of the two species. So wide a range in the time of nesting among the different grackle individuals--April 20 to June 10--prolongs the molting season and occupancy of the roost beyond that of the robin, even with his two broods to rear. If the molted feathers, which were carefully gathered daily, can give accurate information, it is certain that the period of molting is at least a week shorter with the robin than with the grackle The period of incubation is a day or two shorter, and the young leave the nest earlier, how much 1 have been unable to determine accurately In a few isolated cases the young robins have remained in the nest fifteen days after hatching, and the young grackles twenty days But there is considerable variation with both species. The first robin's nest is completed about a week before the first grackle's nest. Thus the more

Product details

  • Paperback | 98 pages
  • 189 x 246 x 5mm | 191g
  • United States
  • English
  • black & white illustrations
  • 1236786416
  • 9781236786418