Our Summer Migrants / An Account of the Migratory Birds Which Pass the Summer in the British Islands.

by James Edmund Harting

Turtle Dove.

Wood Pigeon.

He confirms, moreover, Mr. Rowley’s remark that the Cuckoo’s egg is occasionally found in the nest of the Brambling (Fringilla montifringilla).

I have still to name four species which are not included in any of the above lists, viz., the Spotted Flycatcher, Yellow Wagtail, Grey Wagtail, and Wheatear. They were noticed by me some years ago in the first work I ever published.[101] In the case of the Wheatear, a nest of that bird containing three eggs of the Wheatear and one of the Cuckoo was placed under a clod, and in such a position as strongly to favour the opinion of some naturalists that the Cuckoo first lays her eggs and then deposits them with her bill in the nest.

Considering the amount of attention which has been bestowed upon the Cuckoo by naturalists in every age down to the present, one would suppose that every fact in connection with its life-history was now pretty generally known. Such, however, is not the case. There are still certain points which require investigation, and which, owing chiefly to the vagrant habits of the bird, are not easily determined.

How can it be ascertained with certainty, for example, whether the same hen Cuckoo always lays eggs of the same colour, or whether (admitting this to be the case) she invariably lays in the nest of the same species—that is, in the nest of that species whose eggs most nearly approximate in colour to her own?

And yet we must be satisfied on these points if we are to accept the ingenious theory of Dr. Baldamus. If we understand the learned German rightly, he states that, with a view to insure the preservation of species which would otherwise be exposed to danger, Nature has endowed every hen Cuckoo with the faculty of laying eggs similar in colour to those of the species in whose nest she lays, in order that they may be less easily detected by the foster parents, and that she only makes use of the nest of some other species (i.e. of one whose eggs do not resemble her own) when, at the time she is ready to lay, a nest of the former description is not at hand. This statement, which concludes a long and interesting article on the subject in the German ornithological journal “Naumannia,” for 1853, has deservedly attracted much attention. English readers were presented with an epitome of this article by Mr. Dawson Rowley in the “Ibis” for 1865, and the Rev. A. C. Smith, after bringing it to the notice of the Wiltshire Archæological Society in the same year, published a literal translation of it in the “Zoologist” for 1868. More recently, an article on the subject, by Professor Newton, appeared in “Nature” and elicited various critical remarks from Mr. H. E. Dresser, Mr. Layard, and other ornithologists which deserve perusal.[102]

To enter fully upon the details of this interesting subject would require more space than can here be accorded; one can only glance therefore at the general opinions which have been expressed in connection with it.

If the theory of Dr. Baldamus be correct, is it possible to give a reasonable and satisfactory explanation of it? This question has been answered by Professor Newton in the article to which we have just referred. He says:—“Without attributing any wonderful sagacity to the Cuckoo, it does seem likely that the bird which once successfully deposited her eggs in a Reed Wren’s or a Titlark’s nest, should again seek for another Reed Wren’s, or a Titlark’s nest (as the case may be) when she had an egg to dispose of, and that she should continue her practice from one season to another. We know that year after year the same migratory bird will return to the same locality, and build its nest in almost the same spot. Though the Cuckoo be somewhat of a vagrant, there is no improbability of her being subject to thus much regularity of habit, and indeed such has been asserted as an observed fact. If, then, this be so, there is every probability of her offspring inheriting the same habit, and the daughter of a Cuckoo which always placed her egg in a Reed Wren’s or a Titlark’s nest doing the like.” In other words, the habit of depositing an egg in the nest of a particular species of bird is likely to become hereditary.

This would be an excellent argument in support of the theory, were it not for one expression, upon which the whole value of the argument seems to me to depend. What is meant by the expression “once successfully deposited”? Does the Cuckoo ever revisit a nest in which she has placed an egg, and satisfy herself that her offspring is hatched and cared for? If not (and I believe such an event is not usual, if indeed it has ever been known to occur), then nothing has been gained by the selection of a Reed Wren’s or Titlark’s nest (as the case may be), and the Cuckoo can have no reason for continuing the practice of using the same kind of nest from one season to another.