Origin of Species Variorum

→ OMIT 1869 1872

or not domed 1866

→ in colour to 1869 1872

to 1866

→ Had our cuckoo 1869 1872

had she 1866

↑ 3 blocks not present in 1859 1860 1861 1872; present in 1866 1869

With respect to the last point insisted on—namely, of the young European cuckoo ejecting its fosterbrothers—it must first be remarked that Mr. Gould, who has paid particular attention to this subject, is convinced that the belief is an error; he asserts that the young foster-birds are generally ejected during the first three days, when the young cuckoo is quite power less; he maintains that the young cuckoo exerts, by its hunger-cries, or by some other means, such a fascination over its foster-parents, that it alone receives food, so that the others are starved to death, and are then thrown out, like the egg-shells or the excrement, by the old birds. He admits, however, that the young cuckoo when grown older and stronger may have the power, and perhaps the instinct, of ejecting its foster-brothers, if they happen to escape starvation during the first few days after birth. Mr. Ramsay has arrived at a similar conclusion with respect to the Australian species, which he especially observed: he states that the young cuckoo is at first a little helpless fat creature, but, "as it grows rapidly, it soon fills up the greater part of the nest, and its unfortunate companions, either smothered by its weight, or starved to death through its greediness, are thrown out by their parents."

→ With respect 1872

Now, if it had been of great importance 1866

Now, if it were of great importance 1869

→ means by which this strange and odious instinct was acquired, 1872

young cuckoo to have received as much food as possible during the first few days after birth, I can see no especial difficulty, 1866

young cuckoo to receive as much food as possible soon after birth, I can see no special difficulty 1869

→ if it were of great importance for the young cuckoo, as is probably the case, to receive as much food as possible soon after birth, I can see no special difficulty 1872

if it possessed sufficient strength, 1866

OMIT 1869

→ blind desire, the strength, and structure necessary for the work of ejection; 1872

habit (first, perhaps, through mere unintentional restlessness) and the structure best fitted for ejecting its foster-brothers; 1866

habit (perhaps through mere unintentional restlessness) the strength and the structure best fitted for ejecting its foster-brothers; 1869

→ best developed would be the 1872

would have been the best fed and 1866

would be the best fed and 1869

→ the unhatched young of other 1872

young 1866 1869

→ to break 1872

and the temporary hard tips to their beaks for breaking 1866 1869

→ or than in 1869 1872

or than in the 1866

→ individual variations at all 1872

variation at any 1866

individual variations at any 1869

→ or earlier age,— propositions 1872

age,— propositions 1866 1869

→ OMIT 1869 1872

as we shall hereafter see, rightfully 1866

→ disputed,— 1866 1872

disputed, — then 1869

two of the Australian cuckoos, when they lay their eggs in an open →OMIT nest, manifest a decided preference for nests containing eggs similar →in colour to their own. The European species

certainly

apparently

manifests some tendency towards a similar instinct, but not rarely departs from it, as is shown by her laying her dull and pale-coloured eggs in the nest of the Hedge-warbler with

its

....

bright greenish-blue

eggs:

eggs.

→Had our cuckoo invariably displayed the above instinct, it would assuredly have been added to those which it is assumed must all have been acquired together. The eggs of the Australian Bronze cuckoo vary, according to Mr. Ramsay,

an extraordinary

manner

degree

in colour; so that in this respect, as well as in size, natural selection

assuredly

....

might have secured and fixed any advantageous variation.

In the case of the European cuckoo, the offspring of the foster-parents are commonly ejected from the nest within three days after the cuckoo is hatched; and as the latter at this age is in a most helpless condition, Mr. Gould was formerly inclined to believe that the act of ejection was performed by the foster-parents themselves. But he has now received a trustworthy account of a young cuckoo which was actually seen, whilst still blind and not able even to hold up its own head, in the act of ejecting its foster-brothers. One of these was replaced in the nest by the observer, and was again thrown out. ↑ →With respect to the →means by which this strange and odious instinct was acquired, →if it were of great importance for the young cuckoo, as is probably the case, to receive as much food as possible soon after birth, I can see no special difficulty in its

gradually

having gradually

acquiring,

acquiring

acquired,

during successive generations, the →blind desire, the strength, and structure necessary for the work of ejection; for those young cuckoos which had such habits and structure →best developed would be the most securely reared. The first step towards the acquisition of the proper instinct might have been mere unintentional restlessness on the part of the young bird, when somewhat advanced in age and strength; the habit having been afterwards improved, and transmitted to an earlier age. I can see no more difficulty in this, than in →the unhatched young of other birds acquiring the instinct →to break through their own shells;—or →or than in young

snake

snakes

having

acquiring

its

their

upper

jaw,

jaws,

as Owen has remarked, a transitory sharp tooth for cutting through the tough egg-shell. For if each part is liable to →individual variations at all

age,

ages,