1904] Nesting of Some Canadian Warblers. 67 



one set of egg's in the breeding season: certainly its nesting period 

 in Canada would not allow of it raising more than one brood dur- 

 ing its stay in this country, but where the first clutch of eggs is 

 taken, it will doubtless nest a second time. But, considering the 

 many enemies among the smaller mammals, birds of prey, and 

 reptiles, to which its eggs and young are exposed, it is doubtful 

 if even one brood is raised by the majority of the pairs that cross 

 our national boundary with each return of spring; even in the most 

 protected localities; though the progress of civilization is rather 

 in favor of its increase, except from the presence of the domestic 

 cat; and yet it is wonderful how some nests of our garden — fre- 

 quenting birds will escape the attention of this feline foe. The 

 chief protective means resorted to by this species is by selecting a 

 deep shady spot, either among the thick herbage, vines or young 

 underwood, on, or near the ground; and then, after incubation 

 has begun, and when the female becomes aware of danger, 

 she does not fly directly from the nest, but quietly runs off among * 

 the surrounding shade, and does not take wing till some distance 

 away, nor does she return to her charge till she thinks the danger 

 is over. These eff"orts to protect her progeny, are, so far as human 

 kind are concerned, so successful that very few of its nests are ever 

 discovered; and its eggs are, and are ever likely to remain, a rarity 

 in oological collections, but the case is very difi'erent with the 

 lower orders of carnivorous mammals and snakes which are ever on 

 the search to find and devour the eggs and young of every species 

 that comes within their reach. In this charge the red squirrel, 

 the chipmunk, the weasel, the mink, the skunk, and the fox, are 

 among the chief transgressors that range the haunts of the war- 

 blers, while, nearer human habitations, cats, rats, and even mice, 

 do their deadly work; and no enemy of all the warbler family is 

 more to be dreaded than the vagabond cow-bird. 



During the past twenty years a number of the nests of the 

 mourning warbler have come under my observations, and the 

 finding of these has been rather accidental than the results of con- 

 tinuous field and forest research; but the last of these noted up to 

 the end of the season of 1902, is the first to which attention will 

 here be directed. On the 8th of June, 1902, when strolling across 

 a piece of recently cleared fallow, now over-grown with raspberry 



