14 lU: IvLKTIX OF THK 



THE MIGRATION ROUTE OF KIRTLAND'S WARLER 



CHAS. C. ADAMS. 



About a year ago the relations suggested in this paper gradually took 

 shape and were written out in practically their present form. But at thai 

 time the breeding area or summer home of Kirtlands Warbler was un- 

 known. Since that time the discoveries of Mr. E. 11. Frothingham and 

 Mr. N. A. Wood, in Oscoda and Crawford counties. ^Michigan, have made 

 « it necessary to modify certain statements as they were originally written 

 and at the same time they have added information tending to reinforce 

 others. During the past year more has been added to our knowledge of this 

 bird than during all of the preceding fifty-three years which had elapsed since 

 its discovery. 



At present we are only concerned with the records of the spring Mi- 

 grants, as emphasis is laid upon migration routes and their bearing upon 

 the distribution of the localities from which these migrants have been 

 recorded. The scattered localities from which the birds have been reported 

 seems at first glance, to be very chaotic. This apparent irregularity has 

 been very confusing. 



In the study of bird migration, the routes taken by such birds is of 

 great importance and of special importance in the present case. The only 

 known breeding ground for Kirtlandi is in Oscoda and Crawford Counties. 

 Michigan. Its winter home is in the Bahama Islands. By what routes then 

 docs it pass from its winter home to its summer breeding grounds in the 

 North ? It will be safe to assume that practically all our spring records 

 ot these birds are those of the migrants advancing toward their breeding 

 grounds. In these records then we have exact data as to the migration 

 routes of this species. Migration routes and their significance have been 

 Ciiampioned in this country by Dr. Leonhard Stejneger. of the National 

 Museum, who has said ('99, p. 68) concerning the route of this bird: " The. 

 importance of this question [summer home and migration route] is very 

 great, for. seemingly at least, the distribution of this Warbler suggests a 

 migration route almost unique. Yet, if we accept as our working theory of 

 migration, the only rational one which has been offered to the present day. 

 viz., Palmen's, that the annual migration route of a species indicates thr 

 way by which it originally immigrated unto its present breeding home, 

 how are we going to explain the apparent uniqueness of the route of 



Dcndroica kirtlandi? It will now be seen how desirable it is 



to trace step by step the progress of this species from the Bahamas to ^lichi- 

 gan, and possibly beyond. Here is a species so very strongly differentiated 

 3S not to be mistaken for any other, and so limited in numbers that it 

 probably follows only a single narrowly limited route. When we shall 

 have solved this problem we shall also know a good deal more about the 

 roan by which in past ages part of our fauna entered their present habitat." 



It is not only a point of interest, but also one of importance, as one 

 may see from the foregoing quotation, if we can come to a better under- 

 standing of the facts alreadv known concerning this interesting bird. T 



