112 
and generally have peculiar wavy markings of 
a lighter shade, giving them an appearance 
that distinguishes them from all other American 
eggs. Three eggs are usually laid, but quite 
commonly only two, while some biologists speak 
of sets of four in a nest. The nest is a very 
shiftless structure of a few twigs, and lined 
with catkins, leaves, and sometimes grass. 
The affair is almost level on top, and it is a 
mystery how the eggs are kept on the nest. 
The eggs are often laid several days apart, thus 
differing from general custom with our birds. 
In some nests I have examined a young bird 
was found along with two eggs in various 
stages of incubation. Again, two or three 
young of different sizes were found. Still I 
have seen young of a size in a nest. 
[t is generally allowed that our American 
cuckoos do not share the peculiarity of the 
European bird in laying in other birds’ nests ; 
however, this has been disproved in many in- 
stances where the European habit seems to 
have been introduced, more, however, as an 
exception than otherwise. One bird that we 
NATURE'S REALM. 
have, the cow-bird or cow-bunting (Molothrus 
ater), invariably lays its eggs in other birds’ 
nests, leaving them to the entire care of the 
foster parents. This strange parasite was par- 
tially treated of in the January issue of Na- 
TURE’S REALM. It does not belong to the 
cuckoo family, but to the /cterid@, and is a 
true blackbird. 
In several instances cuckoos’ eggs have been 
found in the nests of other owners, but the ex- 
ceptions are comparatively few; but in cases 
where the two species of cuckoos—yellow-billed 
and black-billed—have joined issue, the num- 
ber of instances is large. It is these occur- 
rences, not rare, where there are five or. six 
eggs taken from a nest, causing an amateur 
collector to think that one bird laid them all. 
By a student the eggs of the two species may 
be readily distinguished. One of our promi- 
nent ornithologists insists that in time the 
American cuckoo will have fully acquired the 
well-known habit now possessed by its Euro- 
pean, congener. 

