r Black-back are much darker, nearly dull sooty black, and
much less margined and marked with pale whitey brown than those of the
Herring Gull. The dark bands on the end of the tail-feathers of the
Lesser Black-back are broader and darker than in the Herring Gull: this
seems especially apparent on the two outer tail-feathers on each side;
besides this, there is a slight difference in the colour of the legs,
those of the Lesser Black-back showing a slight indication of the yellow
of maturity. I have noted these distinctions both from living specimens
of both species which I have kept, and noted their various changes from
time to time, and from skins of both: unfortunately the two skins of the
youngest birds I have are not quite of the same age, one being that of a
young Herring Gull, killed at the Needles in August,--the other a young
Lesser Black-back, killed in Guernsey in December; but I do not think
that this difference of time from August to December, the birds being of
the same year, makes much difference in the colour of the feathers; at
least this is my experience of live birds: it is not till the next moult
that more material distinctions begin to appear; after that there can be
no doubt as to the species. Two young Herring Gulls which I have, and
which I saw in the flesh at Couch's shop just after they had been shot,
seem to me worthy of some notice as showing the gradual change of
plumage in the Herring Gull; they were shot on the same day, and appear
to me to be one exactly a year older than the other; they were killed in
November, when both had clean moulted, and show examples of the second
and third moult. No. 1, the oldest, has the back nearly uniform grey,
and the rump and upper tail-coverts white, as in the adult. In No. 2,
the younger one, the grey feathers on the back were much mixed with the
brownish feathers of the young bird, and there are no absolutely white
feathers on the rump and tail-coverts, all of them being more or less
marked with brown. The tail in No. 2 has the brown on it collected in
large and nearly confluent blotches, whilst that of No. 1 is merely
freckled with brown. But perhaps the greatest difference is in the
primary quills; the first four primaries, however, are much alike, those
of No. 1, being a little darker and more distinctly coloured; in both
they are nearly of a uniform colour, only being slightly mottled on the
inner web towards the base; there is no white tip to either. In