xcvi Journal of Proceedings.
about half grown, and were reared successfully. On two occasions during
July, 1877, I took a pair of Ringdove's eggs and placed them in a Stock-
dove's nest, but both these birds easily forsake their eggs, and they did
so in both these cases. About the middle of the same month I placed a
Sparrow's egg among the eggs of a Sedge Warbler, and she continued to
sit as before until someone disturbed her. On nearly the same date I
placed a young Sparrow, just hatched, among some young Swallows of
about its own age. It was reared, and flew about the 23rd. On the
28th I placed a young Sparrow in a Yellow-hammer's nest with eggs. It
was fed, and afterwards left the nest as usual.
About the middle of July, 1879, I put a Sparrow's egg into a Swallow's
nest containing eggs. It was hatched about the 22nd, when the
Swallows at once began to feed and attend to it, so that it left the nest a
healthy bird about the beginning of August, but their own eggs became
addled.
I may mention that my friend, Mr. J. B. Ellis, of Leicester, placed
some Book's eggs in a Magpie's nest in April, 1878, but only one was
reared, and the young bird did not afterwards build at the same spot, as
Books are said to have done occasionally when placed in Magpies'
nests which happened to be built in a spot where it was desired to
establish a Rookery.
This spring I made several more interesting exchanges during the
months of May and June. About the middle of May there were in our
garden two Greenfinch's nests—the one with five recently-hatched young
and the other with five hard sat eggs. I effected a complete interchange
between the contents of these two nests, and, strange to say, neither bird
deserted. The one to which I gave the young must have been greatly
puzzled to account for all her eggs having hatched during an absence of
a few minutes only, but she took matters as they came, adopted the
young, and tended them till they left the nest. Her perplexities must,
however, have been as nothing when compared with those of the other
bird, whose young had apparently, to coin an expression, un-hatched
themselves back into eggs again ; but, whatever she may have thought, she
tookmatters contentedly, sat upon the eggs, which began to hatch next day,
and the young were duly reared until they were nearly full grown, when
some unknown person took them. A few days later I substituted four
Sparrow's eggs for four Greenfinch's, in a nest in a hedge. These latter I
put into another Greenfinch's nest close by that already contained four
—making eight in all. I next substituted four fresh Sparrow's eggs for
four hard-sat Greenfinch's eggs in a nest in our garden. These latter I
put into a Sparrow's nest in a laburnum tree, taking the Sparrow's out
and putting them, with others (twelve in all, about equally sat upon) into
another Sparrow's nest in the same tree. Thus I had three Greenfinches
sitting, respectively, on four Sparrow's eggs, on eight Greenfinch's eggs,
and on four Sparrows' eggs ; also a Sparrow sitting on four Greenfinch's
eggs, and another on no less than twelve Sparrow's eggs. Just a week
later I ascertained that every one of these experiments were going on
satisfactorily—that is to say, the birds were sitting on the eggs I had sup-
plied them with, and would have reared the young all right had not various
circumstances happened to prevent. The first batch of four Sparrow's
eggs before being hatched were sucked by a Cuckoo, while some of the
second lot proved rotten ; possibly I had chilled them in the removal.
The eight Greenfinch's and the twelve Sparrow's eggs turned out to be,
some of them, more incubated than others, and after the first young were
hatched the other eggs were neglected and became chilled. The Sparrow
hatched the four Greenfinch's eggs, and commenced to rear the young,
but afterwards deserted them, perhaps on account of my disturbing her
too often.