May, 1892.] 



AND OOLOGIST. 



73 



Nesting of the Blue-gray Gnatcatcher. 



It seems strange tliat such an essentially 

 southej-n species as the Blue-gray Gnatcatcher 

 (Polioptila ccerulea) should be so abundant as 

 it is in tliis locality which is so near the limit 

 of its northern range, if not, indeed, actually 

 marking that limit, at least in this state and 

 the neighboring State of Ohio, where, accord- 

 ing to Oliver Davie, it is also quite common. 

 But in Butler and Armstrong Counties, only 

 some forty miles to the eastward of here, it is 

 conspicuous by its absence, a fact in keeping 

 with the boreal affinities of the fauna of which 

 locality, as compared with that of Beaver 

 County. 



Its arrival occurs the third week in April, 

 or, to speak more iirecisely, and by the record 

 on the 17th or 18th of the month, when 

 pleasant weather has become fairly established 

 and the orchard and forest trees are just 

 beginning to burst into new life. Dry and 

 rather open woods, especially if on a hill-side, 

 ai"e its chosen haunts, in which places the 

 birds, although so small of size, may always 

 be found if present by following up their 

 peculiar tiling note, cJiee-e-e-chee-e-e-chec-e-e, 

 wliich cannot possibly be confounded with any 

 other, although on the whole bearing consider- 

 able resemblance to that of the Blue Gt)lden- 

 winged Warbler. But this is a humble effort 

 compared with the Gnatcatcher's true song, 

 for it is possessed of exquisite vocal powers, 

 though they are not often exercised, and not 

 generally known even among professed orni. 

 thologists, its song being heard for only a 

 week or two after the bird's ai-rival. Not so 

 full and clear, indeed, as the vivacious song of 

 its cousin, the Euby-crowned Kinglet, which 

 expressive, and sweeter, well-belitting such a 

 is migrating at the same time, but more 

 exquisitely modulated, more tender, more 

 tiny, fairy-like bird, as, clad in a delicate blue 

 and white, it ceaselessly pursues its minute 

 insect prey in the tree-tops, in every motion 

 graceful. 



They are invariably paired on their arrival, 

 and lose little time in selecting a nesting-site, 

 which is always in the immediate vicinity of 

 last year's, and not infrequently on the same 

 tree. The spot having been chosen, work on 

 the nest is immediately begun, and rapidly 

 carried forward except in stormy weather, 

 though the structure always requires for its 

 final completion between two and three weeks 

 of constant labor on the part of the female, 

 the male, so far as I have observed, never 



assisting, although he always remains near at 

 hand and takes a great interest in the work, 

 aiding no doubt, by his cheery presence and 

 song. The nest is occasionally let down into 

 the crotch of an upright branch, but as a rule 

 is saddled on a horizontal limb, preferably bf 

 an oak, at an elevation of from twenty to fifty 

 feet,- and is not infrequently so arranged as to 

 be directly under another limb, so as to be 

 partially protected from the disintegrating 

 effect of rain. It is a most elegant and elabo- 

 rate structure, a very model of bird architect- 

 ure, and as such very creditable to its tiny 

 owners, whose labor is so patiently expended 

 upon it. Though reminding one strikingly 

 of the nest of the Hummingbird, with which 

 it even vies in elegance of design and beauty 

 of finish, it is much larger, being, in fact, very 

 large in proportion to the size of the bird. 



A nest now before me, collected May 19, 

 1890, and wliich may be regarded as typical, is 

 composed of the delicate stalks of certain 

 small weeds, fine strips of inner bark, bits of 

 dry mullen leaf, down from the thistle, milk- 

 weed, and various other plants, pieces of 

 cocoons, etc. There is no special lining other 

 than the regular material used for the bodj^ of 

 the nest, but the outside is completely and 

 neatly stuccoed over with bluish-gray lichens 

 fastened on by a lavish use of cobwebs. The 

 cavity is deeper than it is wide; the brim is 

 moreover much constricted. The birds very 

 often place their nest on a lichen-covered 

 branch, the more to escape observation, but in 

 any case it might readily be mistaken for a knot 

 on the limb, so perfect is the mimicry. It is a 

 soft and ijerishable structure, loosely attached 

 to its branch, and never outlasting the season 

 for which it is intended. Although it might 

 naturally be supposed that it would be rather 

 difficult to find, this is in reality a very simple 

 and easy matter, as the birds never stray far 

 from home and are always certain to return 

 sooner or later, so that it is only necessary to 

 watch them while building. When the female 

 begins to incubate she every now and then 

 answers the calls of her mate by reassuring 

 notes, thus disclosing the position of her nest. 

 When their domicile is invaded they become 

 very bold and fearless, though so small and in- 

 significant in size, often coming within a yard, 

 scolding and pi'otesting vigorously meanwhile. 

 In a case that came under my notice this last 

 spring, where the female of a pair which had 

 nearly completed their nest was accidentally 

 killed, the male in the course of a few days 

 secured another mate, which built a new nest 



