28 



BULLETIN 185, U. S. DEPARTMENT OF AGRICULTURE. 



Bogoslof after long quests for food, began to break through the fog- 

 wall astern, fly parallel with the vessel, and disappear in the mists 

 ahead. By chart and compass the ship was heading straight for the 



Pig. 12. — Distribution and migration of the redstart (Setophaga ruticUla). An example of a wide migra- 

 tion route. Redstarts cross all parts of the Gulf of Mexico and pass from Florida to Cuba and through 

 the Bahamas, so that their migration route has an east and west width of more than 2,000 miles. (See 

 p. 23.) The opposite of this (a narrow migration route) is shown by the distribution map of the rose- 

 breasted grosbeak, fig. 13. 



island, but its course was no more exact than that taken by the birds. 

 The power which carried them unerringly home over the ocean 

 wastes, whatever its nature, may be called a sense of direction. We 

 recognize in ourselves the possession of some such sense, though 



