192 THE ESSEX NATURALIST.
Red-legged Partridge. Alectoris r. rufa (L.).
Complete .. 0
Complete partial 0
Partial .. .. 10
Total .. 10
Ref.: The Field, vol. 22, p. 559, vol. 81, p. 470 ; The Essex Nat.,
vol. 22, p. 320.
Aggregates.
Complete .. 61 =30.3%
Complete partial 31 =15.4%
Partial .. .. 109 =54.2%
Total .. 201
These figures show that we have knowledge of at least 201
instances of birds having been affected by albinism. In con-
sidering these percentages we must bear in mind that if we effect
a comparison with those of Mr. Pycraft our complete albinos are
only required to be wholly white and not to have the eyes, bill,
legs and feet affected. Of these 201 instances 74 are claimed by
three (Blackbird 36, Starling 24 and Rook 14), from a total of 48
species. These are very common birds, but the high percentage
of albinistic cases is not thus to be completely accounted for.
Even admitting that there are inconsistencies between different
dark-coloured species, as for example between the Blackbird and
the Rook, the latter being probably more numerous than the
former, the evidence shows that sable-hued birds are more
subject to attack than those that have lighter plumages. This
is strikingly shown by comparing the Blackbird (36 cases) with its
close congener the Song Thrush, which can only claim three,
and such an abundant bird as the Wood Pigeon has the same
figure.
Three Essex examples are of interest as they support the
view that red and green may be more resistent to albinism.
A female Robin in the Essex Museum, Stratford, (Plate IX.)
is completely white with the exception of the red breast,
which is apparently unaffected; the retention of the green
rump by a Chaffinch (E. N., v. 22, p. 215) facilitated its