2 MICHIGAN SURVEY, 1908. 



of the birds. He returned on the last boat of the season for Duluth, 

 Minn. 



During the previous (1904) season, the Museum party had made n 

 general examination of the vicinity about Washington Harbor, so that it 

 was now thought desirable to devote more time to other localities. With 

 the exception of bird migration, no detailed work was done in this vicin- 

 ity in 1905. In addition to the region about the head of the harbor, Lake 

 Desor was also reached from this point by means of the road along the 

 crest of the Greenstone Eange. 



2. The Aim and Methods of TFor/i;. The field work was conducted on 

 the same general plan as that pursued during the previous season in 

 the Porcupine Mounitainis and a.t Washinglton Harbor. Much more 

 ground was covered, however, because it seemed improbable that a third 

 trip could be made to the same region. It therefore seemed desirable 

 to gain some idea of the biota of the island as a whole, because of its- 

 Canadian character. Even then, the survey was confined almost exclu- 

 sively to the region south of the Greenstone Range. 



As mentioned in the report for 1904 (Ruthven, '06, pp. 11-12), the aim 

 of the work was not simply to collect specimens, but also to study the 

 relations of the plant and animal life (the biota) to their surround- 

 ings. The environment as well as the biota was considered from a dyn- 

 amic standpoint, and aU effort was made to analyze the environment 

 in order that the dominant conditions and processes of which it is com- 

 posed might be recognized, and their laws of change be perceived and 

 formulated. To resolve such a problem as this must of iiccessitr 

 require more time and detailed investigation than the possibilities of a 

 few months work will permit, and yet it is equally evident that prelimi- 

 nary work should be carried on from a genetic standpoint, because such 

 a method determines upon what facts emphasis should be placed, and th'* 

 broader and more general relations, as well as the details, are equally 

 subject to a genetic and dynamic treatment. In preliminary work of 

 this character, it is considered of special importance to discover, if pos- 

 sible, the order of the major biotic successions, because these succes- 

 sions must be clearly perceived before their causes can undergo ade- 

 quate analysis. Our knowledge of causes generally lags far behind our 

 recognition of successions. 



Thus throughout the study of the Isle Royale biota a special effort 

 was made to investigate the genesis or successions of events. The en- 

 vironment has not been considered as limited to habitats alone, but 

 also to include that greater unit, the geographic. To ignore this is 

 to overlook the real background. It is believed that certain advantages 

 are derived from this method of work, which, although they may be 

 recognized from other points of view, are likely to be subordinated to 

 other facts. It should not for a moment be thought that this method is 

 considered as the only one of approach, but it appears to have certain 

 advantages which seem to justify its adoption. Nor should it be inferred 

 that the genesis of the biota and the habitat is all that should be in- 

 cluded in an ecological survey. The problem of succession is only one of 

 several which clearly show the intimate relations and responses between 

 organisms and their environment ; others tliat remain, to be investigated 

 involve physiological and structural changes, and various modifications 

 of habit and behaAior of both plants and animals. 



