THOMAS] BIRD MIGRATION BY WHITE OF SELBOURNE 397 



love and hunger. As to love, that is out of the question at a time 

 of the year when that soft passion is not indulged; besides, during 

 the amorous season, such a jealousy prevails between the male 

 birds that they can hardly bear to be together in the same hedge 

 or field. Most of the singing and elations of spirits of that time 

 seem to me to be the effect of rivalry and emulation; and it is to 

 this spirit of jealousy that I chiefly attribute the equal dispersion 

 of birds in the spring over the face of the country." The reason 

 for the early retreat of the swift baffles- him completely and he says, 

 "This early retreat is mysterious and wonderful, since that time is 

 often the sweetest season of the year. Are they regulated in their 

 motions with us by a failure of food, or by a propensity to moulting, 

 or by a disposition to rest after so rapid a Hfe, or by what?" The 

 reasons for migration became still more complicated when he con- 

 sidered the case of little birds. ' ' We make great inquiries concern- 

 ing, the withdrawing of the swallow-kind," he says, "without 

 examining enough into the causes why the summer short-winged 

 birds of passage are never to be seen in the winter. The swallows 

 are often found in a torpid state: but red-starts, white-throats, 

 black-caps, etc., are very ill provided for long flights; have never 

 been found once, as I ever heard of, in a torpid state." 



Though it seemed incredible that birds, especially the little ones, 

 crossed the Mediterranean and we have evidence that people 

 believed that they rode across on the backs of big turtles. White 

 reasons that they do not expose themselves to long oversea flights, 

 saying, " It does not appear to me that much stress may be laid on 

 the difficulty and hazard that birds must run in their migrations, 

 by reason of vast oceans, cross winds, etc., because, if we reflect, a 

 bird may travel from England to the equator without launching 

 out and exposing itself to boundless seas, and that by crossing the 

 water at Dover, and again at Gibraltar. And when arrived at 

 Gibraltar, they scout and hurry along in Httle detached parties and 

 sweeping low, just over the surface of the land and water, direct 

 their course to the opposite continent at the narrowest passage 

 they can find." 



He gives an amusing explanation of the gregariousness of birds of 

 various species in the fall migration, that are not used to living 

 together at other times. "If I admire when I see how much 

 congenerous birds love to congregate, I am the more struck when 

 I see incongruous ones in such strict amity. If we do not much 



