Dec. 1887.] 



AKD OOLOGIST. 



203 



Most of the readers of the O. and O. know 

 that a few of the first primaries of many birds 

 (as the Baptores^ some herons, and a few other 

 birds), are cut emarginately in a peculiar 

 way. Now these birds are often on the wino; 

 for hours at a time, and as the muscle that 

 opens the primaries' pulls on a lever of the sec- 

 ond order, the strain on that muscle would be 

 very great to constantly keep the primaries 

 open. But there is a way by which this ujuscie 

 can be relieved. 



The bird contracts the extensor muscle that 

 governs the first five or i-ix primaries, at the 

 same time giving a slight rotary motion, so 

 when the extensor muscle is relaxed, the pri- 

 maries that are emargiuate are locked into one 

 another, the first feather beliind the second as 

 far as the cutting goes, the second behind the 

 third as far as its cutting extends, and so on 

 with the rest of the primaries. 



This locking relieves the muscle and leaves 

 the primaries extended without muscular exer- 

 tion. The process of unlocking is very simple, 

 and entirely under control of the bird. It will 

 be noticed that the upper edge of each feather 

 is cut down to correspond with the cutting of 

 the lower margin of the preceding feather. 

 Thus, the feathers arc not only locked, but have 

 a firm bearing against each other to resist the 

 pressure of air underneath the wing. 



This is not confined to soaring birds alone, 

 but it is safe to say that whenever this einar- 

 ginate cutting is found, it is to enable the bird 

 to lock its feathers. 



This is not a matter of speculation, but ob- 

 servation upon birds which have been shot. A 

 full description and cut will be published in the 

 next number of ''The Transactions" of the 

 New York Academy of Sciences. 



Runt Eggs and Their Cause. 



BY .). r. N. 



Eggs of a smaller size than those usually laid 

 by the species in question, are, if the difterence 

 is very marked, known as " runts." They usu- 

 ally occur in small nujubers and are quite rare. 

 It is seldom that more than one runt is found 

 in one set of eggs, though a very notable ex- 

 ception to this rule will be referred to below. 



Their cause seems to be twofold — either they 

 result from exhaustion of the bird from laying 

 an unusually large number of eggs, or they ai'e 

 the product of young females. 



A set of eggs of Wood Thrush {Hylocichla 

 mustelina) found near Milton, Mass., on May 



26, 1883, has two of the eggs nmch larger than 

 usual, measuring 1. 13 x. 04 and 1.09 x. 82, while 

 the other two measure only .87 x .03, and .88 x 

 .G3, and are runts of the most pronounced type. 



A set of eggs of Downy Woodpecker {Pints 

 pubesceus) collected near Nazareth, Penn., on 

 June 8, 1882, has five eggs, four of whi«h are 

 normal size, while the fifth only measures .G(ix 

 .54. 



The most remarkable runt eggs which have 

 ever been found are i)robably a set of five of 

 the Worm-eating Warbler {Hchnintliot /writs vcr- 

 micurus) found by Mr. Samuel B. Ladd near 

 West Chester, Penn., on June 11, 1887, and de- 

 scribed in Thk OHNrTUOL<)(iisT and Ooi.ocist 

 for July, 1887 (Vol. XII., p. 110). The average 

 size of the egg of this species is about .08 x 54. 

 but Mr. Ladd's wonderful set measure .4(» x .3G ; 

 .4(5 X. 36; .45x.37; .42 x .36 and .42x.3C. In 

 shape and colorings they are perfect miniatures 

 of the full-sized eggs of this Warbler. As they 

 were the seventeenth set which Mr. Ladd took 

 in the same locality they were probably the 

 last eftbrt of a female who had laid two previ- 

 ous sets, which she had been deprived of. 



A runt egg of the Yellow Warbler (Dendroeca 

 (estiva) measures .45 x .35 and is perfect in its 

 shape and coloration. 



Golden Crested Kinglet at Grand 

 Manan. 



BY CHAS. H. ANDKOS. 



I include this species simplj'^ to mention a 

 nest taken by Mr. Cheney a short time before 

 our arrival at his home. Though, undoubtedly, 

 nests have been taken since that found by Dr. 

 Brewer, his is the only authentic instance with 

 the exception of the incomplete set taken 

 by Dr. Northrup at Caribou, Maine, which 

 enters into detail that I have yet seen in 

 any New England work. Mr. Minot's nest 

 found in New Hampshire, contained young. 

 My regret is that I did not more carefully note 

 the measurements and material which enters into 

 the make up of Mr. Cheney's nest. It is a beau- 

 tiful piece of architecture, shaped much like the 

 home of the Blue-grey Gnat-catcher, but is 

 much larger and deeper. Internally, it is lined 

 with soft down and wool, and contains about 

 six cubic inches. From edge of nest to bot- 

 tom exteriorly, measures about five inches, and 

 the thickness of nest wall at top nmst be about 

 one-half inch. Externally, the nest is covered 



