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brown, the primaries margined externally with ashy grey, the secondaries with greyish white, giving 
them a hoary appearance; tail greyish brown, the feathers edged with pale ashy grey, becoming hoary 
white on the two outermost ; entire throat sooty black, with a very few whitish margins to the lateral 
feathers ; rest of the under surface of the body dull white, inclining to brownish on the flanks and 
thighs; under wing-coverts dull white; bill blackish horn-colour; feet leaden-brown; iris reddish 
brown. Total length 4°6 inches, culmen 0:4, wing 3°45, tail 2°2, tarsus 0°65. 
Female in summer plumage. Rather duller than the male, especially underneath, and having the secondaries 
edged with the same ashy brown as the back, instead of having the margins hoary grey. 
Winter plumage. In winter the plumage is decidedly more fluffy, the margins to the quills and tail-feathers 
are broader, causmg the hoary appearance on the outer edge of the secondaries to show with greater 
distinctness. The black feathers on the throat are all margined with whitish. 
Obs. Notwithstanding that many good ornithologists unite in considering the present species as syno- 
nymous with the Common Marsh-Titmouse, we have no hesitation in declaring our opinion that it is 
quite a distinct bird, the characters by which it is known being as follows :— 
1. The head is dull sooty black, without any blue gloss as in P. palustris; and the black crown is continued 
far down on to the interscapulary region, being bordered for its whole extent by the white cheeks and 
sides of the neck. 
2. The colour of the back is ashy grey, and not nearly so brown in P. palustris. 
5. The edges to the secondaries are whitish, and very distinct. 
4. P. borealis is rather larger, and, according to the testimony of several observers, differs in habits and in 
its note. 
Mr. R. Collett, who has carefully investigated the question as to the validity of this species, fully believes 
that it is perfectly distinct from the Marsh-Titmouse, and grounds his belief on the following facts which have 
come under his personal observation. He writes to us:—‘‘This species affects spruce woods, whereas the 
Marsh-Titmouse prefers non-evergreen woods; the call-notes of the two species differ considerably, that of the 
Northern Titmouse being sharper, and the final ek more lengthened, and as if divided into two notes; the 
nests of the two species differ considerably in structure.’ Mr. Collett gives the distinctive characters 
categorically ; and we cannot do better than translate what he says on the subject, as follows :—‘ Parus 
palustris has the cap black, with strong reflections, and it extends only to the nape, whereas in P. Jorealis it 
is plain black without gloss, and extends on to the back. P. palustris has the cheeks white only under the eye, 
otherwise light grey; whereas the cheeks of P. borealis are white all over and all round, only being divided 
by the cap. In P. palustris the closed wing is narrowly edged with dark brown, whereas in P. borealis it is 
broadly edged with light grey, almost white. The colour of the back in P. palustris is brownish, and in 
P. borealis grey. The outer tail-feather in P. palustris is about 1 line shorter than the middle one, and in 
P. borealis 34-4 lines shorter. The nest of P. palustris is always placed in healthy non-evergreen trees, 
whereas that of P. borealis is always in a dead stem or branch; and P. borealis forms the hole itself, whereas 
P. palustris makes use of any old hole. The nest of P. palustris is constructed of moss, feathers, and straws, 
whereas that of P. borealis invariably is constructed of bast (or fine bark strips), and sometimes a few hairs or 
feathers.”” Our own observations, it will be seen, agree almost precisely with those of Mr. Collett; but we 
cannot accept as of specific importance the difference in the graduation of the tail-feathers; for we have found 
specimens of P. borealis with a perfectly square tail, and P. palustris with a graduated one. Further evidence 
as to the distinctness of the two birds is adduced by Mr. Wheelwright, who observes in his ‘Spring and 
Summer in Lapland’ :—“T believe it is, however, admitted now that this Parus borealis, De Selys, is nothing 
more than the northern form of the Parus palustris. ‘To me the note appears very different ; and I invariably 
