194
THE ESSEX NATURALIST.
of the total 109 partially affected birds 31.2% are symmetrical
and 12% asymmetrical. These figures would seem to show
that there is a marked tendency towards symmetry but if we had
descriptions of the 62 unplaced cases the position would pro-
bably be considerably altered. The necessity for detailed de-
scriptions of affected individuals is here specially evident. There
is one case of symmetry which is worthy of mention. A White-
throat (Christy) had completely normal plumage with the
exception of the alulae, both of which were white.
Of the total number of birds admitted to the Essex list 121 are
resident at some time or other and they thus comprise what may
be called the permanent avifauna of the county. As we have
knowledge of only 48 species which have had albinistic individuals,
and although it is probable that many more species have been
affected than have been recorded, yet there are absentees which
are notable. The fact that no instance of albinism in any of the
titmice has been recorded, remembering the abundance of this
group, demands at least notice.
XANTHISM.
Greenfinch. Chloris c. chloris (L.).
Complete .. 0
Complete partial 0
Partial .. .. 1
— A mixed white, creamy and yellow colour.
Total .. 1 Included also under albinism.
Ref.: The Birds of Essex (Christy).
Chaffinch. Fringilla c. coelebs L.
Complete .. 0
Complete partial 0
Partial .. .. 1
— Light yellow with the exception of white
Total .. 1 wing bars. Symmetrical.
Ref. : The Field, vol. 74, p. 545.
Yellow Bunting. Emberiza c. citrinella L.
Complete .. 1 Nestling. Parents and other young
normal.