This and the Hirundo albicollis, (first named by M. Vieillot) are two of the largest species yet discovered, of a very singular group of Swifts; wherein the tail feathers are spined, and even more rigid than those of the Woodpeckers: by this structure the birds can remain for a considerable time in the most perpendicular situations. The expanded tail thus acts as a powerful support, which is further increased by the size and strength of the claws, much larger than those of ordinary Swallows. There are several species, most of which are natives of America.
The direct analogy which this group bears to the typical scansorial Birds, joined to the general superiority of flight which the Swift possesses over the Swallow, leads us to suspect this may prove to be the typical group of the Fissirostres; an order in which Nature, in her wish to develope the greatest powers of flight, appears to neglect all those laws which she afterwards so rigidly adheres to: We intend in another work, to enter on this interesting subject more fully.
Our figure is in strict conformity with the scale on the plate, which is that of an inch.
Pl. 43.
PETROICA bicolor.
Black & white Robin.
PETROICA bicolor.
Black and White Robin.
