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No. 110: Mar-Apr 1997

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Sparrows At Play

While looking through the ornithological literature for avian anomalies recently, we found an irresistible item that bears on that deeply profound bit on "Crow Woes" appearing in SF#109. Remember how the Yokohama crows placed stones on the train tracks and dropped others on houses? Well, this stone-dropping must have some adaptive value in the evolution of birds, because sparrows have also inherited the trait. E.C. Jaeger recounted this anecdote in a 1951 number of The Condor:

"During my high school days at West Point, Nebraska, my father was a merchant occupying a building of two stories with a long pebble-covered, tarred roof sloping to the rear. Forming a short walkway behind the rear entrance were two sloping doors, which, when opened up, admitted entry to the basement stairway. Over a period of several days in mid-May of 1903, I noticed many small pebbles scattered about on these doors. I also heard from time to time the sound of small objects falling on the doors. Efforts to find the pebble-droppers were of no avail until one day when I happened to approach the rear of the building from the alley. My position some fifty feet from the building now permitted me to see several House Sparrows (Passer domesticus) bringing small stones to the edge of the roof and dropping them. As each pebble was dropped the bird involved turned its head to one side, apparently the better to listen to it and watch it as it struck the door. It may have been a sort of bird pastime; it certainly was an activity of no evident value."

(Jaeger, Edmund; "Pebble-Dropping by House Sparrows," The Condor, 53:207, 1951.)

From Science Frontiers #110, MAR-APR 1997. 1997-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987