220 NORTH AMERICAN BIRD.^. 



The wondei-rul sa.L;.acity displaveil by tliis AVaililcr in avdidiii^ the disa- 

 greeable alternative of either havintr to abandon its own nest or of rearintr 

 tlie young of the intrusive Vow Blackbird, wlien one of tliese eggs is dropped 

 in her nest, was first noticed by Mr. Xnttall. The egg oi' the parasite, being 

 too large for ejectment, is ingeniously incarcerated in the bottom of the nest, 

 and a new lining built over it. Occasionally, either by accident or design, 

 the intrusive egg has been fractured. Mr. Nuttall states that where the 

 parasitic egg is laid after her own, the Summer Yellow-Bird acts faithfully 

 the part of a foster-jjarent. This, however, is not according to my observa- 

 tions. In several instances I have known the Summer Yellow-Bird utterly 

 refuse to act the part of a foster-parent, and, rather than do so, sacrifice her 

 own eggs. So far as I know, this Warbler will never sit upon or hatch out 

 the egg of the C'owbird, under any circumstances. Some powerful instinct, 

 bordering closely u]3ou reason, seems to teach these intelligent A\'arlilcrs the 

 character of the intruder, and tliey .sacrifice their own eggs ratlier tiian rear 

 the parasite. In tliis diUuama they will always, so far as I know, incarcer- 

 ate their own eggs with the Cowbird's and reconstruct the nest above them. 

 In one instance tiie same pair of Yellow-Birds twice, in the same nest, cov- 

 ered u]i alien eggs in this manner, building, in fact, three nests one above 

 tlic otiier, between the walls (if whicii had been successively included two 

 eggs of the Cowbird. This three-storied nest measured seven inches in 

 length, and was built almost exclusively of raw cotton. The covering of the 

 imprisoned eggs was about two thirds of an iiu-h thick. In bnth instances 

 the Cowbird's eggs had been broken, apparently by design. 



So far as I am aware tiiis Warbler raises but one brood in Massachusetts 

 in a season. In Pennsylvania it is said to raise two, and even three. The 

 eggs are usually five and occasionally six in number. 



This Warbler is conspicuous in its devotion to its young, evincnng a strong 

 attachment ami an anxiety in regard even to an unoccu])ied nest, and be- 

 traying the site by this solicitude. Tliev will also resort to vari()\is exj)edi- 

 ents to draw one away from their nest, b}' feigned lameness and other strata- 

 gems and rnanonivres. 



The song of tiie Summer Yellow-Bird is siuqilc but ]. leasing, and is easily 

 recognized when once known, though liable to he confounded with that of the 

 Maryland Yellow-Tlu'oat, and also said to resemble the song of several other 

 Warblers. 



In confinement they usually become very tame, confiding, and reconciled 

 to their imprLsonment, and iiave been known to perch on an outstretched 

 finger, and to catch flies in a room. 



Their eggs vary in length from .61 to .70 of an inch, and in l)readth from 

 .49 to .52. They have a ground-color of a liglit green. Their dots and 

 blotches vary greatly in number, size, and manner of distrib\ition. Their 

 colors are light purple, ilarker pur]ilish-br(i\\ii, and other shades of brown 

 and lilac. 



