Origin of Species Variorum

→ nest. 1859 1860 1861 1866 1872

nest. If this were the case, the process of laying and hatching might be inconveniently long, more especially as she migrates at a very early period; and the first hatched young would probably have to be fed by the male alone. 1869

→ asserted 1859 1860 1861 1866

both asserted and denied 1869 1872

→ hear on the high authority of Dr. Brewer, that this is a mistake. 1859 1860 1861 1866

have lately heard from Dr. Merrell, of Iowa, that he once found in Illinois a young cuckoo together with a young jay in the nest of a Blue jay ( Garrulus cristatus ); and as both were nearly fully feathered, there could be no mistake in their identification. 1869

have lately heard from Dr. Merrell, of Iowa, that he once found in Illinois a young cuckoo together with a young jay in the nest of a Blue jay (Garrulus cristatus); and as both were nearly fully feathered, there could be no mistake in their identification. 1872

↑ 1 blocks not present in 1859 1860 1861 1866 1869; present in 1872

I could also give several instances of various birds which have been known occasionally to lay their eggs in other birds' nests.

→ or 1859 1860 1861

through being enabled to migrate earlier or through any other cause; or 1866 1869 1872

→ by 1859 1860 1861 1866

when reared by 1869 1872

→ then 1859 1860 1869 1872

and by having to migrate at a very early period; then 1861

and by having to migrate at an early period; then 1866

→ could be, and 1859 1860 1861 1866

OMIT 1869 1872

she lays her eggs, not daily, but at intervals of two or three days; so that, if she were to make her own nest and sit on her own eggs, those first laid would have to be left for some time unincubated, or there would be eggs and young birds of different ages in the same →nest. If this were the case, the process of laying and hatching might be inconveniently long, more especially as she

~~has to~~

has to

migrates

migrate

at a very early period; and the first hatched young would probably have to be fed by the male alone. But the American cuckoo is in this predicament; for she makes her own

nest,

nest

and has eggs and young successively hatched, all at the same time. It has been →asserted that the American cuckoo occasionally lays her eggs in other

birds

birds'

nests; but I →hear on the high authority of Dr. Brewer, that this is a mistake. ↑

~~Nevertheless,~~

Nevertheless,

I could

also give

give

several instances of various birds which have been known occasionally to lay their eggs in other

birds

bird's

birds'

nests. Now let us suppose that the ancient progenitor of our European cuckoo had the habits of the American

cuckoo,

cuckoo;

and

but

that

she occasionally

occasionally she

laid an egg in another

birds

bird

bird's

nest. If the old bird profited by this occasional

habit

habit,

→or if the young were made more vigorous by advantage

being

having been

taken of the mistaken

~~maternal~~

maternal

instinct of another

species,

species

bird,

than →by their own

mothers

mother,

mother's

~~care,~~

care,

encumbered as she

could

can

hardly fail to be by having eggs and young of different ages at the same

time,

time;

→then the old birds or the fostered young would gain an advantage. And analogy would lead

to believe, that the young thus reared would be apt to follow by inheritance the occasional and aberrant habit of their mother, and in their turn would be apt to lay their eggs in other

birds

birds'

nests, and thus be

more successful

successful

in rearing their young. By a continued process of this nature, I believe that the strange instinct of our cuckoo →could be, and has

been

been,