Secrets of animal life / by J. Arthur Thomson.

  • Thomson, J. Arthur (John Arthur), 1861-1933.
Date:
1919
Catalogue details

Licence: In copyright

Credit: Secrets of animal life / by J. Arthur Thomson. Source: Wellcome Collection.

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    selves in all probability in a region which they never before visited. Furthermore, as Bird Key is the last piece of land between the coast of Florida and the coast of Texas, the birds can be sent out to sea for hundreds of miles beyond sight of all land- marks. Between Bird Key and Galveston, for instance, there is open water for 855 statute miles, obviously a fine expanse for homing experiments. The technique of the experiments is as follows : A bold, vigorous tern is caught, it is marked char- acteristically with oil-paint on the head and neck ; two tags (small and large, but otherwise duplicate) are prepared, recording the date, the place, and the kind of marking ; the small tag is tied round the bird’s neck ; the large tag is fixed to a foot-long stake pushed down into the sand near the nest if the bird is a Sooty or tied to a convenient twig if the bird is a Noddy ; the bird is put into a large hooded cage and transported to a distance on board ship ; it is kept in good health with minnows from the refrigerator ; it is liberated at a chosen point; and then its return to the nest is watched for. The most important general result is that these terns pxe able to return from Galveston, more than 800 miles away, over a body of water which apparently does not offer any basis for con- trolling flight direction. Some returned in about six days, some took nearly twelve, some did not return at all. Many of the return journeys from distances greater than 500 miles did not require more than three to five days, but sometimes as