88 CHUCK-WILLD’S-WIDOW—CITRIL 
a mountaineer, and does not affect a sea-shore life.. A single 
example has occurred in England, and is figured in Mr. Aplin’s 
Birds of Oxfordshire, but the possibility of its having escaped from 
captivity is not to be overlooked, though the species has reached a 
spot so distant from its home as Heligoland. ‘The Alpine Chough 
is somewhat smaller than its congener, and is easily distinguished 
by its shorter and bright yellow bill. Remains of both have been 
found in French caverns, the deposits in which were formed during 
the “Reindeer Age.” Commonly placed by systematists next to 
Pyrrhocorax is the Australian genus Corcoraz, represented by a single 
species, C. melanorhamphus, but osteologists must be further consulted 
before this assignment of the bird, which is chiefly a frequenter of 
woodlands, can be admitted without hesitation. 
CHUCK-WILL’S-WIDOW, so syllabled in North America from 
the bird’s cry. One of the Caprimulgidx (GOATSUCKER), Antrostomus 
carolinus, much larger than but congeneric with the WH1p-PooR- 
WILL, A. vociferus. 
CHURN-OWL, one of the many names of the common NIGHT- 
JAR of Europe. 
CIRCULATION, or circulatory system, signifies motion of the 
blood, which is pumped by the heart through the blood-vessels. 
Birds, like Mammals, possess a complete double circulation, namely 
(1) that of the body, from the left ventricle of the heart into the 
aortic arch, thence through the arteries of the body, returning by 
the veins into the right auricle, and (2) the pulmonary circulation, 
from the right ventricle into and through the lungs, returning by 
the pulmonary veins into the left auricle, and thence into the left 
ventricle (see VASCULAR SYSTEM). 
CITRIL, the name under which Ray and Willughby in 1663 
became acquainted at Vienna with a Finch, and now occasionally 
used for it in German, though it is more commonly known as 
Citronenfink, the allusion in each case being to the colour of its 
plumage, which some consider to be of a citron hue, but is mostly 
of a yellowish-green. ‘The bird is the Venturon of the French, the 
Chrysomitris citrinella of modern ornithology—a common species in 
southern and parts of central Europe, but seldom occurring much 
further northward than the Black Forest. It usually frequents 
mountainous districts, keeping to the neighbourhood of fir-trees, 
though chiefly feeding on the seeds of grasses and other lowly- 
growing plants. 
meant ‘‘patted” or footed (cf the heraldic croix patée), and that therefore it 
refers to this bird with its red feet. Others maintain that ‘‘russet” did not 
necessarily mean red, but was frequently used for grey, and accordingly that 
the Daw with its grey head was intended. 
