TROCHILID^, HUMMINGBIRDS. 269 



b. borealis. 



Ojpselus borealis, Keisn., Pr. Phi la. Acad, ix, 1857, 202. 



Ciwscloules borealis, Scl., P. Z. S. 1865, 615. 



Nephocwtes niger, Bd., B. N. A. 18.^.8. 142.— Elliot, B. N. A. i, pi. 20.— CoOP., Orn. Cal. i, 



1870, 349.— SuMiCH., Mem. Bost. Soc. i, 1869, 562 (Vera Cruz). 

 Xephmceies niger var. borealis, Coues, Key, 1872, 183. 

 Xephcecetes niger, B. B. & R., N. A. B. ii, 1874, 429, pi. 45, f. 4. 



Hab.— The typical form iu Cuba and Jamaica. Var. borealis from the Pacific coast, 

 United States ; south into Mexico. 



'; 



Family TROCHILIDiE : Hummingbirds. 



The Hummers constitute a very large family of very small birds, and form one of 

 the most remarkable groups in ornithology. Sharply distiDguished from all other 

 birds, no less by their general appearance than by their technical characters, they are 

 recognizable at a glance by the casual observer, and some representatives are familiar 

 objects to all, from the vast numbers that are set up all over the civilized world merely 

 for ornamental purposes, and the gratification of the cnrious. They compete with 

 Ostrich and Bird of Paradise plumes, Rooster's hackles, Gull's breasts, and other mis- 

 cellaneous objects of natural history in the decoration of woman's head-apparel ; and 

 are prominent features of bird-stufter's show-cases. Beautiful even under such condi- 

 tions, in the more favorable circumstances of their native haunts they are the most 

 lovely of the feathered denizens of the air, gorgeous in color, exquisite in form, won- 

 derful in action. 



Notwithstanding the ease with which these birds as a group may be known, some 

 technical comments will not be out of place here. With ordinal characters of Picariw, 

 they associate a medium to extremely long and very slender, subulate, or even acicular 

 bill, usually straight and acute, with inflected tomia, serrate or not, and short unl>ristled 

 gape. In some remarkable species, as the Docirnastes ensiferus, the bill is actually longer 

 than all the rest of the bird, a thing not elsewhere known among birds ; and iu general, 

 it is longer than the head. The tongue is peculiar ; it resembles that of the Wood- 

 peckers, in its length and lumbriciform sleuderness, as well as its susceptibility of 

 being protruded to great distance by means of its posterior prolonged " horns," that 

 curve around the skull; but in structure it is double-barrelled, consisting of two 

 thready tubes, an arrangement which, in connection with the tube-like sloping of the 

 niouthj facilitates the extraction of honey from the nectaries of flowers, by a peculiar 

 process that may be true voluntary suction, or a sort of capillary attraction, or partly 

 both. 



The wings are remarkable in several respects. In general, they are thin, sharp, and 

 pointed, with long, stiff", curved primaries, rapidly graduated, and short secondaries, 

 resulting iu the shape especially to be called falcate. They have but six remiges, in 

 addition to the ten primaries. The upper arm-bone is extraordinarily short; perhaps 

 representing the extreme of this condition among birds. The breast-bone is very large, 

 and has an enormous keel; this is in relation to the immensely developed pectoral mus- 

 cles that move the wing. The whole conformation illustrates perfectly a well-known 

 law, yet one not often mentioned, respecting the movements of the wing of a bird, viz., 

 that the nearer to the body the longest quill-feather is, the more rapidly is the wing 

 moved. We will assume, for example, what is very near the truth, that a Humming- 

 bird and an Albatross have about the same relative length of wing in the ''hand" or 

 pinion portion that bears the ten primaries, and the same relative length of these 

 quills. In the Albatross, this portion of the wing is widely separated from the body 

 by the length of the humerus and fore-arm; in the former, the reverse extreme exists; 

 and we see the result in the long, measured sweep of the ocean-bird's wing and the 

 rapid strokes of the other's. This is in strict accordance with a mechanical law 

 respecting the ratio between time of motion and distance traversed. Given, say, a 

 Hunnner's wing two inches from flexure to tip of first primary, and one inch from 

 flexure to shoulder-joint; this would make th<' point of tlie wing describe ar. are of a 

 circle with a radius of three inches; and a certain amount ofnuiscnlar eontraetion 

 effects this in a certain time. Now, lengthen fore-arm and upper-arm till they are 

 each about two inches long, which would be something like the relative lengths in an 

 Albatross' wing; this would make t4ie point of the wing move in the arc of a circle 

 with a radius of six inches. Now, the muscular ibrce remaining the same, it is evi- 

 dent that the point of the wing could not move through this nnich larger arc in the 

 faiime tune; i. c, the wing-strok«;s WDuld be necessarily slower. It is interi'sting to 

 observe how, in some other birds, ;i .similar result is brought about by dilferent means. 

 In a Partridge, for instance, without special shortening of upper-arm or fore-arm, the 

 longest quill-feather is brought nearer the body by the roundness of the wing, that is, 



