Cygnus immutabilis, Yarrell.*
THE POLISH SWAN.
Gygnus immutabilis.
Some of the London dealers in birds more than forty
years ago appear to have been in the habit of distinguishing
a large Swan, which they said they received from the Baltic,
by the name of the Polish Swan. The Author had reason
to believe that this Swan would prove to be a distinct
species, though even more nearly allied externally to our
Mute Swan, than the Bewick’s Swan is to the Whooper.
In the spring of 1836 the Ornithological Society of London
purchased of the late Mr. Castang, the dealer in birds, a
pair of these Polish Swans, with one cygnet of their own
brood, which was white. This appeared to be a specific
peculiarity worthy of consideration ; the parent birds were
remarkable besides in having the legs, toes, and their intervening
membranes of a pale ash-grey colour; the black
tubercle at the base of the beak was of small size ; and the
elongated openings in the nostrils did not reach the black
colour at the base of the beak, on each side, but were
entirely surrounded by the orange colour of the beak, as
shown in the representation. Unfortunately, both the old
female and the young bird died in the following winter.
The old male had but a small tubercle at the base of the
beak, and his legs and feet, though a little darker than
formerly, continued of a pale slate-grey. This bird did not
pair, and could scarcely be said to associate with any of the
Mute Swans on the same water.*
In the severe weather of January and February, 1838,
Swans of all sorts were unprecedentedly abundant; and several
specimens were obtained out of flocks of these Polish Swans
which were seen pursuing a southern course along the line
of our north-east coast, from Scotland to the mouth of the
Thames. The specimen which the Author exhibited at the
evening meeting of the Zoological Society, belonged to the
Rev. L. B. Larking, of Ryarsh Vicarage, near Maidstone, and
was one of four shot on the Medway, near Snodland Church,
where a flock of thirty and several smaller flocks were seen.
The circumstance of these flocks being seen without any
observable difference in the specimens obtained, all of which
were distinct from our Mute Swan; the fact also that the
cygnets, so far as then observed, were of a pure white colour,
* About 1852, th e th ir te e n th E a rl of Derby having only a female of th e
Polish Swan, an d th e Ornithological Society still possessing th e ir solitary old
male, th e la tte r was se n t to Knowsley, to form a p air. F o u r cygnets were p io
duced, which were white when b atch ed , an d remained so. A t th e sale of th e
Knowsley collection th e two old b ird s were p urchased by Mr. B a rtle tt for th e
Ornithological Society, an d placed on th e lak e in St. J am e s’s P a rk . They p ro duced
a brood of seven cygnets in th e summer of 1854, a n d an o th e r of six in
1855, which were a ll w h ite from th e egg. A male Polish Swan p a ire d w ith a
Mute Swan a t Knowsley, an d a brood was produced. A Polish Swan also p aired
with a Mute Swan on th e w ate rs in th e Phoenix P a rk devoted to th e use of th e
Dublin Zoological Society.