13 



the fall migration the younger birds lead,* in the spring they loiter be- 

 hind, and it is the old birds, those in whom we may suppose the love 

 of home and the desire for procreation are strongest, which press for- 

 ward so eagerly. Moreover, of these old birds, those which arrive first 

 at a given place, as a rule, are birds which lived there the previous 

 summer and which will remain there to breed.f Thus the vanguard is 

 constantly arresting itself, and the forward movement must await the 

 arrival of the next corps, which may be near at hand or far in the rear. 

 The movement of migration, then, is made up of a series of constant 

 overlappings, and the real speed is evidently much greater than the 

 apparent. Of this real speed of transit we can take no account, and our 

 calculated rates, therefore, are of value only in so far as they show the 

 relative speed of migration of the different species. In the accompany- 

 ing report the speed of migration is calculated in the following manner: 

 The most southern reliable record is selected for comparison with the 

 most northern record of the same character ; the distance in miles be- 

 tween these two stations is divided by the number of days elapsing from 

 the time the species made its appearance at the southern station to the 

 date at which it was seen by the northern observer. The result gives 

 the average daily rate of migration in miles for the species. For exam- 

 ple : The Baltimore Oriole was seen at Rodney, Miss. (lat. 31° 52 ; ), April 

 7. It was not seen at Oak Point, Manitoba (lat. 50° 30'), until May 25. 

 It was therefore 48 days in passing over the 1,298 miles between the 

 two stations, which gives an average speed of 27 miles a day. This 

 subject will be treated as thoroughly as possible, since it has received 

 little or no attention heretofore 5 indeed, there were no data in existence 

 for its study until the notes were collected on which the present report 

 is based. 



The first records published in this country relating directly to the 

 speed at which birds travel appeared in the Ornithologist and Oologist 

 for January, 1884 (pp. 1 and 2). These notes were based on the records 

 of six species in the spring of 1883 ; and though the notes for 1884 are 

 many fold more numerous they do not give grounds for a change in 

 the general rate of speed set forth in that article. It must be kept 

 constantly in mind, however, that no complete and scientific study of 

 the subject is as yet possible, and that the present records are given 

 merely because they are the best now obtainable, and because they 

 may furnish some material for the use of the future student. 



The records of fifty-eight species for the spring of 1883 give an 

 average speed of 23 miles a day for an average distance of 420 miles. 



[* The opinion here expressed by Professor Cooke, namely, that in fall young birds 

 migrate before their parents, has been long accepted in Europe, but is contrary to 

 the experience of most leading American ornithologists and to the evidence collected 

 by the Committee on Migration of the American Ornithologists' Union, as will appear 

 in a future publication of the Division. See, also, Mr. Brewster's recent essay on the 

 subject, in the Memoirs of the Nuttall Ornithological Club, — C. H. M, J 



L[+This statement needs much qualification. — C. H. M.] 



