336 University of California Publications in Zoology [Vol. 11 



REMIGES 

 Macroscopic Structure 



The most highly specialized and most important feathers of 

 the entire body are the remiges, or flight feathers, composed of 

 the two groups, primaries and secondaries, the former borne on 

 the hand, the latter on the forearm. 



Circus hudsonius is a bird of strong flight, and though not 

 known to sail or soar to the extent of some of its aquiline and 

 buteonine relatives, it is very graceful on the wing, combining 

 in its usual mode of progression a buo.yant, easy gliding, with 

 occasional series of long, strong wing strokes. Though not 

 indulging in it as frequently as many of the buteonine hawks, 

 the harriers are capable of a similar spiral sailing. It is a 

 migratory species, undertaking flights of long duration in the 

 spring and fall. 



As might be expected of such a bird, the flight feathers are 

 very highly developed and specialized. There are ten primaries 

 and fourteen secondaries, which produce a long, ample, moder- 

 ately pointed wing, with a comparatively^ shallow concavity from 

 front to back. The wing is approximately of the same relative 

 size as is that of Buteo, but is somewhat more pointed. This is 

 due to the fact that the third and fourth primaries are con- 

 siderably the longest, with the second and fifth next, equivalent 

 to each other, while the first primary is somewhat shorter than 

 the sixth. In the more rounded wing of Buteo the third, fourth, 

 and fifth are nearly equal, while in the more pointed wing of 

 Falco sparverius the second and third primaries considerably 

 outdi-stance the others. 



The third primary, one of the longest ones, maj^ be described 

 advantageously as a typical primary, the points wherein the 

 others differ from it being dealt with subsequently. The total 

 length of the feather is 286 millimeters, of which 47 form the 

 calamus. The latter is not quite circular in section, measuring 

 3.68 millimeters in diameter in the plane of the vanes, and 

 4.34 millimeters in the plane at right angles to them. It tapers 

 suddenly at the root. A short distance above the superior 



