Correspondence. 103


I fear, Sir, that your reviewer was rather led away by Mr. Beebe's

positive bluster, for the fact that a single individual has moulted can by no

stretch of imagination be called overwhelming proof. Because I have not

published anything on this subject since my paper in the 'Ibis' for 1900, I

am by no means the less certain that colour-change does take place, nor

have I ceased to accumulate careful notes of every occurrence that has

come under my observation. I have not had the opportunity of observing

the change on the American Laughing Gull, but have repeatedly done so

on our native and nearly-allied species, L.ridibundus. If a number of these

birds be taken in February and March, especially in the earlier half of the

latter month, the colour of the feathers of the head will, in an overwhelm-

ing percentage of individuals, be found to be much darker than in an equal

number of birds taken during the earlier months of the winter. The

earlier birds will all be found very uniform, showing a pure white head with

darker patches near each eye and ear-covert; the February and March

birds, on the other hand, will show a large amount of individual variation,

some being very nearly as in winter, others showing two dark crescentic

bars from eye to eye and ear to ear, while in others again the wholeof the

back of the head will be of a dark sooty brown. If these birds be shot and

the skins examined, both inside and out, no trace of new growing feathers

will be found, and if this alteration is not caused by colour-change I should

like to hear Mr. Beebe's explanation of it.


So much for wild shot birds : now let us turn to birds in confinement,

where this species does extremely well, and what do we find ? In February

and March the birds can be observed getting darker day by day. I have re-

peatedly observed this in many individuals; gradually the black colour-

spreads across the head from the eye- and ear-patches till we get two black

crescentic bars; the space between these bars then gets darker, and finally

the dark colour creeps forward towards the cuhnen, the whole change

taking place in about ten days or a fortnight, and during that time, how-

ever closely the bird ma}' be examined, no 11 eiv feathers appear.


The change is, however, not as a rule complete, although it is ex-

ceptional!}* so, as in an instance I had this year, but, as a rule, the colour-

change stops short of completeness, a few white feathers are left and the

dark colour is not so intense as in a full-plumaged bird. In this condition

it will remain for two or three weeks, and then supervenes the moult of

which the Americans are never tired of telling us. I have restricted my-

self to the Black-headed Gull, but precisely similar changes are found in

some Waders and doubtless in many other species.


Although it is the twentieth century (to paraphrase Mr. Beebe) I am

not alone in my belief of colour-change as an interesting note on the

Herring-Gull from the pen of Dr. Gadow in the ' Field' for Nov. 24th will

show. That a feather, although fully grown is not dead, was clearly shown

at the last meeting of the Zoological Societv, where I exhibited a-Kuo±!s^



