at establishment, but, unluckily, no note as to date or locality has
been preserved; he told me he had killed this bird late in the spring,
but could not when I saw him remember the exact date. It must not be
supposed that because this bird occasionally remains in the Islands late
into the spring, and assumes its full breeding-plumage before leaving,
that it ever remains to breed or avails itself of the protection so
kindly afforded to it and its congeners, as well as their eggs, by the
Guernsey Bird Act.

The Great Northern Diver is included in Professor Ansted's list, but
only marked as occurring in Guernsey. There are four specimens in the
Museum in full breeding plumage and change.

154. BLACK-THROATED DIVER. _Colymbus arcticus_, Linnaeus. French,
"Plongeon a gorge noir."--The Black-throated Diver is a much less common
visitor to the Islands than either the Great Northern or Red-throated
Diver; it does, however, occasionally occur in the autumn and winter;
all the specimens that have been obtained are either immature or in
winter plumage, and I do not know of a single instance in which it has
been procured in full plumage as the Great Northern has. In the
'Zoologist' for 1875 Mr. Couch records the occurrence of a
Black-throated Diver on the 19th of January of that year, and of another
on the 30th of the same month; these are the most recent occurrences of
which I am aware. No doubt the young Black-throated Diver may be
occasionally mistaken for and passed over as the young Northern Diver;
but it may always be known by its much smaller size, being intermediate
between that bird and the Red-throated Diver, from which, however, it
may always be distinguished by wanting the white spots on the back and
wing-coverts which are always present in the winter plumage of the adult
Red-throated Diver, and the oval marks on the margins of the feathers of
the same parts in the young birds of the year.

The Black-throated Diver is included in Professor Ansted's list, and
marked as only occurring in Guernsey. There is one specimen, an immature
bird, in the Museum.

155. RED-THROATED DIVER. _Colymbus septentrionalis_, Linnaeus. French,
"Plongeon a gorge rouge," "Plongeon cat-marin."--The Red-throated Diver
is a regular autumn and winter visitant to the Islands, and rather the
most common of the three Divers. As with the Northern Diver, it
occasionally remains until it has nearly assumed its full
breeding-plumage, but it does