YELLOW-BILLED CUCKOO. 393 
grey; irides dark brown, orbits greyish white. There is no external 
difference between the sexes; but young birds are said to be without the 
chestnut on the primaries, as in the Black-billed Cuckoo, from which they 
may always be distinguished by the yellow on the bill. 
An example of the Black-billed Cuckoo (Coccyzus erythrophthalmus) was 
shot by Dr. Rea at Killead, ten miles from Belfast, near the end of 
September 1871. It was erroneously recorded (‘ Zoologist,’ 1872, p. 2943) 
as a Yellow-billed Cuckoo; but Lord Clermont subsequently identified it as 
the black-billed species (‘Zoologist,’ 1872, p. 3022). The only other 
example obtained in Europe occurred in Italy near Lucca in 1858 (Bolle, 
Journ. Orn. 1858, p. 457). Newton, in his edition of Yarrell’s ‘ British 
Birds,’ does not devote an article to this species, though in the ‘ Ibis List? it 
is mentioned without brackets. It is very difficult to determine whether an 
American bird, which has only appeared once or twice in Europe, should 
be included in the British list or not ; but much may be said in favour of 
excluding American birds that have only once been obtained in our islands. 
Many species of American birds occasionally wander far from home, and 
some habitually visit the Bermuda Islands. Most of these birds which 
visit this country are inhabitants of the north-west of America, many of 
them even breeding on the Siberian coast; and there can be little doubt 
that they travel across Asia, appearing on our islands in the great stream 
of migration which reaches us in autumn from the east. It seems pro- 
bable, however, that others cross or attempt to cross the Atlantic—birds 
that have lost their way in migrating southwards from Labrador, or have 
been driven out to sea by heavy gales. Probably the greater number of 
these birds perish ; but some succeed in reaching Europe with or without 
the help of an occasional rest on the rigging of some of the numerous 
ships crossing the ocean. 
The Black-billed Cuckoo inhabits the eastern half of the North-American 
continent, breeding as far north as Labrador, and as far south as Georgia 
and Texas. In winter it is found in Mexico, Central America, some of 
the West Indies, and the northern portions of South America. The habits 
of this bird differ little from those of the Yellow-billed Cuckoo. Its egg 
is figured on Plate 68. They vary in length from 1:15 to 1:05 inch and 
in breadth from ‘9 to *8 inch. The eggs of the Black-billed Cuckoo are on 
an average considerably smaller than those of the Yellow-billed Cuckoo ; 
but small eggs of the latter are indistinguishable from large eggs of the 
former. 
The Black-billed Cuckoo may be distinguished from its near ally by 
being slightly smaller, by having very little chestnut on the primaries, 
both mandibles of the bill nearly black, the orbits dull scarlet, and the 
white tips to the tail-feathers much less conspicuous. The sexes do not 
differ in colour. 
