DISTRIBUTION AND HABITS OF THE ROBIN 11 



ditions; nevertheless, in the course of its extensive migrations, 

 ifc may at least pass over such tracts. Thus I have observed 

 large flocks in the open and sterile portions of Dakota and 

 Montana flocks that were journeying across the country, and 

 had stopped for rest and food in the fringe of trees along the 

 lesser water-courses. 



It is not easy to determine the center of abundance of so 

 widely diffused a bird as the Eobin. Excluding the extremes 

 of its range, reached by comparatively few individuals, such 

 as Greenland, the West Indies, or Central America, its num- 

 bers appear to be determined solely by the food-supply. Since 

 settlement of the country and cultivation of the soil result in 

 an increase of its favorite articles of diet, it is nowhere more 

 numerous than in populous districts. In the Southwest, it 

 appears to be becoming more abundant than it formerly was, 

 doubtless in direct consequence of the progress of civilization. 

 All the recent observers who have recorded their experience 

 agree in their representations to this effect. In any given 

 locality, short of the extremes of its range, the bird appears to 

 be more abundant during the migration especially the autum- 

 nal movement than at other seasons. This may be due to two 

 causes. In the first place, there is an actual increase in number 

 by new arrivals ; and, secondly, the birds collect together in 

 large companies, and become in consequence more conspicuous 

 than they are when generally dispersed. In some regions, 

 where trees are few and far between, as in an instance already 

 cited, Eobins will rarely be se6n except in the spring and fall. 

 In intermediate portions of the United States, they seem to be 

 most numerous early in the spring, and in the latter part 

 of autumn, when straggling flocks of hundreds roam through 

 favorite tracts of woodland and shrubbery, or betake them- 

 selves to the neighboring fields. 



The Robin is strictly a migratory bird, like most insectivor- 

 ous species which inhabit the northern hemisphere. There is 

 a general north and south movement of the species as a whole, 

 during the changing seasons of the year a movement directly 

 related to the sources of food-supply. Nor should it be in- 

 ferred from the fact that Eobius may be seen in a given locality 

 during the whole year, that the tide of migration has not 

 passed ; for it may be that the individuals present at one 

 season are not the same as those that remained during a pre- 

 vious period of the year. The fact appears to be, that, as a 



