BICKNELL'S THRUSH 209 



thrushes in captivity taking greedily to fresh lettuce. Stomach 

 analyses did not disclose this dietary feature, as leafy items, if present 

 at all, are quickly passed, thus escaping detection. Possibly leafy 

 matter may play a more important part in a bird's natural diet than 

 commonly supposed. One caged bird was kept in good condition on 

 a seemingly well-balanced diet of fresh meat (to replace insects), 

 lettuce, and fresh fruit. The lettuce seemed to provide the bulky 

 matter necessary for proper elimination. 



The foregoing evidence relating to food habits of these thrushes 

 clearly indicates their tendency to prey heavily upon injurious insects, 

 and, as Beal (1915b) appropriately remarks, "the vegetable food, 

 drawn entirely from nature's storehouse, contains no product of 

 human industry, either of grain or fruit. Whatever the sentimental 

 reason for protecting this bird, the economic ones are equally valid." 



Behavior. — So many of the specific or racial characteristics of these 

 thrushes have been mentioned in the preceding text that it is necessary 

 to add only a few summarizing remarks under this caption. Ordi- 

 narily in their summer haunts only fleeting glimpses are caught of a 

 brownish-olive form slipping quickly from view into concealment. 

 Sometimes they are flushed when foraging on the ground among the 

 ferns or brush or briefly viewed darting across an opening among the 

 evergreens; or, more often, seen perched at evening upon a balsam 

 spire, calling and singing. Because of their reputed shyness and 

 wariness, their habit of occupying the most inaccessible places, and 

 their almost unbroken silence during much of the year, they have 

 come to be known, perhaps undeservedly, as one of the rarest, shiest, 

 and least known of American passerine birds. Citations from early 

 observers for the most part only serve to heighten this impression of 

 obscurity, but Langille (1884) and Bent (MS.), in writing of their 

 Seal Island experiences, and Torrey (1892), referring to observations 

 on Mount Mansfield, reported them relatively friendly and not 

 particularly shy. 



Much of the obscurity prevailing regarding this form may stem 

 from the fact that observers are seldom on hand at the time when the 

 bird can best be studied. Their period of greatest activity is in June, 

 at the height of the black-fly season, when the mountains are relatively 

 unpopular. In addition the thrushes are so quiet during midday, 

 owing to extensive morning and evening activities, that short daytime 

 excursions into their haunts are seldom conducive of good results. At 

 the height of the breeding season, however, the writer found these 

 birds to be delightful study subjects. Though by nature somewhat 

 shy and wary, nesting birds, particularly the female, seldom took very 

 serious alarm at intrusions, and blinds were erected in close vicinity ? to 

 several nests without the adults appearing unduly^ concerned. One 



