230 FRANCIS H. HERRICK 
TABLE 7 
Record of American cuckoos' eggs laid in foreign nests 
NO. OP 
CASKS 
NEST OWNERS 
INTRUDERS 
INTRUSIVE 
REMARKS 
EGGS 
1 
Yellow-billed cuckoo 
Black-bill 
1 
1 
Cedarbird 
rJlack-bill 
1 
1 
Cardinal 
Black-bill (?) 
2 
fcuckoo species 
l^not determined 
2 
Yellow warbler 
T>1 „1 U ■ 1 1 
Black-biU 
1 .1 
2 
Chipping sparrow 
Black-bill 
1 :i 
1 
Wood pewee 
Black-biU 
1 
r 
Black-bill 
Mourning dove. 
Owner laid 1 
1 
J 
Robin < 
A 
\ egg, and the 
[intruders 2 each 
1 
Catbird 
Black-biU 
1 
3 
Catbird 
Yellow-bill 
1:1:1 
3 
Robin 
Yellow-bill 
1:1:2 
3 
Black-billed cuckoo 
Yellow-bill 
1:1:1 
1 
Wood thrush 
Yellow-bill 
1 
1 
Dickcissel 
Yellow-bill 
1 
1 
Black-throated sparrow 
Yellow-bill 
1 
1 
Cardinal 
Yellow-bill 
1 
1 
Mourning dove 
Yellow-bill 
1 
N. Y., in which the latter speaks of finding three species of birds 
using the same nest. After stating that he had often found the 
eggs of the black-bill in the nests of the yellow-billed cuckoo, but 
in those of no other species but once, he gives the following ac- 
count : ' ' June 17, 1882, 1 found a black-billed cuckoo, and a mourn- 
ing dove sitting on a robin's nest together. The cuckoo was the 
first to leave the nest. On securing this I found it contained two 
eggs of the cuckoo, two of the mourning dove, and one robin's 
egg. The robin had not quite finished the nest when the cuckoo 
took possession of it and filled it nearly full of rootlets; but the 
robin got in and laid one egg. Incubation had commenced in 
the robin and cuckoo eggs, but not in the mourning dove's egg. 
I have the nest and eggs in my collection." It is a pity that this 
remarkable struggle of instincts was not allowed to reach a con- 
clusion. The case, however is one of exceptional interest to the 
student of animal behavior, but in interpreting it we must be care- 
ful not to be misled. It feeems to give us a picture of one of the 
early steps through which parasitism must have passed, perhaps 
