COLE ON THE MIGRATIONS OF BIRDS. 09 



and if i)<)ssible, in whicli the young diftVi' fi-oni both. ^Yil]l ]»i'opoi- in- 

 structions accompanying tliosc bhin]<s, records could be gathered from 

 -svliicli the movements of the species couhl be mapped with considerable 

 assurance, and incidentally the distribution and relative abundance at 

 the different stations tlnoughout the year could be ascertained. IJglit 

 would also be thrown upon many vexing questions which are awaiting 

 settlement. For instance, do the birds remain in the neighboihood 

 after breeding, or do they move northward as is supjxtsed to be the case 

 with some species? Do the obi birds or the young lead in the fall migra- 

 tions? This is a (piestion upon which there is considerable dilference 

 of opinion among writers at present, and is a vital point in the recently 

 advanced theory of Capt. G. ]\eynaud^ on the orientation of animals, 

 in which he advances the theory of a ''sixth sense," which he calls the 

 "law of reliacement" or "law of reverse scent." He says,- "When the 

 time f(U' departure is come, birds of the same species, inhabiting the 

 same region, come together for the journey. Those that have already 

 made the voyag<' lake the lead and retrace the i)ath by which they canu^ 

 The younger birds, born since the last journey, confine themselves to 

 following their elders, and when, some months later, it becomes time 

 to return, these are able in their turn to follow in a reverse direction 

 the journey previously made." Here is a (juestion of fact tluit must be 

 settled by observation before we can seriously consider the theory'. 

 Again, Is it the young birds that are most apt to stray from the 

 regular paths of migration? Does the species in migrating ad- 

 vance as a whole, or is it "like a game of leap-frog," the birds 

 in the rear continually passing tliose ahead, as a flock of passenger 

 pigeons is said to advance across a field when feeding? IIow definitely 

 do birds return to the same locality every summer? Do their routes 

 of migration vary from year to year? These and many other questions 

 could, I believe, be settled by a line of study such as I have indicated, 

 and would open the way to a consideration of the little-understood 

 "homing instinct" of animals, which ])robably reaches its highest develoj)- 

 meut in birds, enabling them to reach a delinite destination ovei- hun- 

 dreds of miles of land and sea, often without any landnuirk for guidance, 

 even su])posing that they make use of such helps. This faculty appears 

 especially remarkable to one who has seen the murres and other water 

 birds of Bering Sea returning thiough the ever-i>resent fog to their 

 nests on one of the few islands Avhich afford them a home. As the boat 

 approaches land, which is hidden from sight and its jtrescnci^ and direc- 

 tion known to the navigator only by the help of his charts, long, bioken 

 lines or smaller flocks of these birds are seen flying lapidly by. There 

 is no hesitation, no uncertaintv; thev mav swerve aside from curiosity 

 to pass near and in.'^pect the shij). but the flight is tluMi continued in the 

 former direction. AMiat can giiide these creatures where the vision 

 is limited to a small ex})anse of gray water enveloped in cloud? Cer- 

 tainly it cannot be the direction of the wind, as maintained by some, 

 for the Avind does not always blow in the same direction, and may even 

 not blo-sv at all. 



'Revue des Deux Mondes. C'XI.VI, .'580-402. Translation in Annual Report Smiths. Inst, 

 for 1898, pp. 481-4!>S. 



=Smiths. Rcpt. for ]8!)8. p. 490. 



