Our Summer Migrants / An Account of the Migratory Birds Which Pass the Summer in the British Islands. :: THE MARSH WARBLER. ( Salicaria palustris. )

THE MARSH WARBLER. ( Salicaria palustris. )

In appearance this bird resembles the common Reed Warbler, just as the Aquatic Warbler resembles the Sedge-bird. It is one of the plain-backed species, and similarity in appearance as well as in habits causes it doubtless to be overlooked or mistaken for the commoner bird.

From its general resemblance to the Reed Warbler, Salicaria strepera[28] (Vieillot), it has no doubt been overlooked; but when its distinguishing characters have been duly noted it will in all probability be found to be a regular summer migrant to this country. Dr. Bree, when treating of this species in his “Birds of Europe,” says (vol. ii. p. 74): “I think it very probable that this bird is an inhabitant of Great Britain, though hitherto confounded with the Reed Warbler. I think I have myself taken the nest; and Mr. Sweet’s bird, mentioned by Mr. Yarrell, was probably this species.”

In the “Zoologist” for 1861, p. 7755, the occurrence of the Marsh Warbler in Great Britain was recorded by Mr. Saville, who procured a single specimen, subsequently identified by Mr. Gould, and saw others in Wicken Fen, Cambridgeshire. He says: “My attention was first attracted to this species some time since, during a visit to our fens, by the marked difference in the song of a bird somewhat similar in appearance to the true S. arundinacea (i. e., strepera); it was louder, clearer, and sweeter-toned than that of the last-named. Its mode of flight, too, was more undulated and quicker. It was more shy and timid, continually retreating to the thickest covert. Never, so far as my experience goes, does it emit notes similar to the syllables ‘chee-chee-chee’ so common to S. arundinacea.”

Another specimen of this bird was obtained in Cambridgeshire by the late James Hamilton, jun., of Minard, during the summer of 1864, and was exhibited at a meeting of the Natural History Society of Glasgow in February, 1865, as recorded by Mr. E. R. Alston in the “Zoologist,” 1866, p. 496.

In the same year, Mr. Robert Mitford gave an account (“Zoologist,” 1864, p. 9109) of a Reed Warbler which he found nesting in lilac trees in his garden at Hampstead, and which at the time was thought to differ specifically from S. strepera, and possibly to be S. palustris. In the summer of 1863 Mr. Mitford had found four pairs of this bird breeding in gardens under similar circumstances, and in July, 1865, he shot two of the same birds, both males, and found, as he says, “two nests similar in structure, and similarly situated to those of the previous year in my garden, from both of which the young had evidently flown only a few days previously. The birds were not in good order, but just beginning their moult. I so arranged the matter that at the time I shot these birds I received from Romney Marsh fresh-killed specimens of the true Reed Warbler, shot in the reeds of the fen ditches; and in comparing the two birds in the flesh together, I have little hesitation in saying that the inland warbler is not our Reed Warbler. I will not enter into the chief points of difference at present, as I hope next May to get a specimen or two in finer plumage.” (“Zoologist,” 1865, p. 9847.)

Mr. Mitford I believe has not altered the opinion which he originally expressed; but, from a careful examination of the birds shot by him, I am inclined to regard them all as S. strepera. This peculiarity in the Reed Warbler of nesting at a distance from water has since been noticed by naturalists in other parts of the country. In 1866 I referred to a confirmation of the fact as communicated by a friend at Ealing,[29] and Mr. A. C. Kennedy, in his “Birds of Berks and Bucks” (p. 81), has alluded to the same habit from his own observation near Windsor. In all probability the birds seen by Lord Clermont in lilac bushes at Twickenham[30] were also Reed Warblers.

Mr. Frederick Bond some time since called my attention to the occurrence of the rarer S. palustris in Norfolk, and kindly lent me a series of skins of both species procured in Cambridgeshire, Norfolk, and Sussex. Of these, two specimens of S. palustris were killed at Whittlesford, Cambridgeshire, many years ago, under the impression that they were S. strepera; and three others near Norwich in June, 1869, under the like misapprehension. They do not differ in any way from skins of palustris from France and Germany, with which I have compared them.

The characters by which this species may be distinguished from S. strepera may be briefly stated as follows:—

Although the colour of the upper portion of the plumage in both is a uniform olive-brown, S. palustris is yellower. It is a somewhat longer bird, with a shorter and broader bill; a buffy-white line, extending from the base of the bill over the eye, is clearly defined. In strepera this line is so faint as to be scarcely discernible. Mr. Yarrell, indeed, considered it to be absent in strepera; but, from this circumstance, and from the fact of his describing the legs of this species as pale-brown, it may be inferred that he had before him, and figured, a young bird.

The first primary in the wing of both is very short, quite rudimentary, in fact; while the third in each is the longest in the wing. In palustris the second primary is equal to the fourth; while in strepera the second is equal to the fifth. It is doubtful whether this can be invariably relied upon, for the length of feathers, even in the same species, will sometimes vary considerably, through age, moult, or accident.

The readiest means of distinguishing the two birds at a glance will be by the colour of the legs and toes. In living or freshly-killed specimens it will be observed that the tarsi and feet of strepera are of a slaty-brown colour, while in palustris the same parts are flesh-colour. In dried skins, the former turns to hair-brown; the latter to yellowish-brown. The tarsus of palustris, moreover, is rather longer and stouter than that of its congener. From this it appears that Mr. Gould in his “Birds of Great Britain” has figured palustris for strepera.

Dr. Bree, in his “Birds of Europe,” has unfortunately figured palustris with slate-coloured legs and feet, which quite alters its appearance, although he has been careful in the text to describe the colour correctly.

The tail in palustris is less rounded than in strepera; the outer tail-feather in the former being not so short as in the latter.

The measurements of the two species, taken from skins, are as follows:—

	Length.	Bill.	Wing from carpus.	Tarsus.
S. strepera	5·3 in.	0·5½	2·7	0·8
S. palustris	5·5 in.	0·5	2·5	0·9

The nests and eggs differ as much as do the birds themselves.

The nest of palustris is much neater and more compact, and, as regards depth, not more than half the size of that of strepera. The eggs of both are subject to variation; but, as a rule, it may be said that in those of palustris the white ground colour has little if any of the greenish or brownish tinge with which those of strepera are invariably suffused.

I have seen two nests in the collection of Mr. Bond, one containing three, and the other two eggs, taken at Whittlesford, which I have no doubt belonged to palustris.

In Badeker’s work on the eggs of European birds, it is stated that the Marsh Warbler “builds in bushes, in meadows, and on the banks of ditches, rivers, ponds, and lakes. The nest is made of dry grass and straws, with panicles, and interwoven with strips of inner bark and horsehair outside. The rim is only very slightly drawn in. It has a loose substructure, and is by this and its half globular form, suspended on dry ground between the branches of the bushes or nettles, easily distinguished from the strongly formed nest of S. strepera, which is moreover built over water.[31] It lays five or six eggs the beginning of June, which have a bluish-white ground, with pale-violet and clear brown spots in the texture of the shell, and delicate dark brown spots on the surface, mingled with which are a number of black dots. The ground colour also in many fresh eggs is green, but clear, and very different from the muddy tint of the egg of the Reed Warbler. The female sits daily for some hours; but the male takes his turn. Incubation lasts thirteen days.”

It would be extremely satisfactory to establish the fact of the regular migration to this country in spring of the Marsh Warbler; and it is to be hoped that ornithologists in all parts of the kingdom will not omit to investigate the subject, and record their observations.

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