THE OOLOGIST. 



45 



eifect, this is not coincided with by all the- 

 orists. We give another explication of the 

 phenomenon of flight : The wings when 

 operated in flying, have a motion backward, 

 and the position of the surface when so em- 

 ployed, is inferior to the horizontal, the arm 

 being the lowest point. The force neces- 

 sary to accomplish buoyancy and progress, 

 thus bends up the quills, so when the wing 

 is forced downward and backward, the un- 

 der surface of the feathers is brought di- 

 rectly against the air. On its return, the 

 wing is contracted and assumes a position 

 at a sharp angle with that used in the back- 

 ward motion, striking tbe air edgewise. 

 Though taken from a standpoint somewhat 

 different from the argument of the Duke of 

 Argyle, the theory comprehends very much 

 the same principles. Of course the natural 

 lightness of the bird is not ignored, when 

 we speak of its buoyancy, but almost every 

 body is heavy in space. 



Regarding the wings of a bird as to the 

 method of flight, i. e., the manner of giv- 

 ing the stroke, we have a topic of but very 

 little less interest than the above. If one 

 would observe the way in which the stroke 

 is made by several birds, and compare this 

 with the shape and size of the wing, he 

 will find that the force of the stroke more 

 or less, is essentially the same in birds 

 whose wings are alike. Take for instance 

 the long, slim wings of the Sparrow Hawk, 

 Night Hawk, Killdeer Plover, the Gulls 

 and some others. It will be seen that the 

 stroke is sharp, quick, jerky and repeated 

 very regularly. Again, observe the simi- 

 larity of stroke of the wings of the Robin, 

 Blackbird, Thrush, etc. Their wings are 

 formed the same ; the flight is even, some- 

 what irregular and steady. The same 

 principle exists throughout the class of birds, 

 perhaps somewhat less applicable in cases 

 of unusual or rare formation of wings. 

 Birds with broad, stiff- feathered pinions 

 are enabled to sail for hours at a time ; nar- 

 row-winged birds are deprived of this gift, 

 and 'though they occasionally spread their 

 wings and retain them so without a mo- 

 tion, it is only for a brief interval previous 



to alighting. 



There is a wide dissimilarity existing in 

 the anns of birds as to their size and strength 

 considering the bulk of the bird. It is well 

 known that birds of large pinions and con- 

 sequent ability to maintain a continued 

 flight for a long period, especially in the 

 case of Eagles, Hawks and other large 

 birds, possess unusually large arm-bones 

 and muscles. We may quote, as an illus- 

 tration of the comparative size and strength 

 of these organs, those of the Carrier Pig- 

 eon and Ruifed Grouse, the former pos- 

 sessing nearly dovible the wing-strength of 

 the latter, though not so large a bird. 

 Could a Song Sparrow assume a size cor- 

 responding to the strength of its wings, 

 were they endowed with the power of those 

 of the Chimney Swift, in comparison to the 

 size of this bird, it would equal that of a 

 Pigeon. Inversely, the degree of strength 

 in an Elagle's wing, compared with that of 

 a Rufl^ed Grouse, considering the bulk of 

 each, would metaphorically, indicate a bird 

 of about a Pigeon's size. Thus we can 

 point out numberless interesting peculiari- 

 ties concerning the flight of birds, and are 

 often impressed with their manifest mar- 

 velousness. 



jlrrheT'tccLTh (^trds. 



The Barred Owl. 



i^Syrnium nehulosiim.) 



CHAS. E. COLES. 



r-£\ HIS species is abundant throughout 

 i 1 the United States. They are noc- 

 turnal in their habits, coming forth 

 only in the night in quest of their prey. 

 They pair early in March and begin to 

 build about the middle of April, sometimes 

 earlier. The nest of the Barred Owl is 

 usually built in a fork at the top of a large 

 oak, elm or beech, among the thick foliage. 

 It is a loosely constructed affair, being com- 

 posed of small sticks, twigs, sods etc., lin- 



