SUBORDINATE MARKINGS OF FEATHERS OF BIRDS. 301
The results of the examination were that subordinate bars
were found on some part or parts of every skin examined. It
came to my mind as being possible that all feathers had bars,
although they might not always be visible. I found it impossible
to give the bars a colour, and I have recorded them as approxi-
mating to the colour of the adjacent part of the feather. In
many instances it is only after changing the position of the
plumage in relation to the light many times that bars can be found.
The best description of these subordinate bars is to liken them
to the markings of watered silk. The bars are transverse and
more or less at right angles to the shaft of the feather. Some-
times they stretch fully across the feather, at times only partially
so, and in some cases only one web is affected. The bars vary
in width, but at all times can only be described as narrow. The
bars at times can be seen only on part of the length of the feather,
at other times the whole length of the feather is affected ; in the
case of a Great Tit twelve bars were counted and nineteen on
the tail of a Masked Shrike. In some instances the bars can be
seen only on the upper side and sometimes only on the under-
side of the feather and at times on both. The 903 skins, which
formed the main part of the enquiry, although not selected for
date, had been obtained somewhat evenly over the twelve months
of the year, the extremes being 39 in July and 109 in September.
The bars were found on feathers of twenty-six colours. The
whole of the plumage was examined to determine the range of
barring over the bird and it was found on sixteen parts of the
plumage, but more frequently on the tail and flight feathers.
The barring varied very much in intensity between different
birds and different parts of the same bird. A comparison of
the intensity of the barring between individuals of the same
species shows that in nineteen instances the male was more
intensely barred than the female, in fourteen instances the female
was more intensely barred than the male, in nine instances the
adult was more intensely barred than the immature, and in
sixteen cases the immature was more intensely barred than the
adult. Variability is probably the most noticeable feature of the
subordinate barring of the feathers of birds. Some types of
feathers seem to be more prone to barring than others. It
appears to be more noticeable in iridescent and other feathers
with highly glazed surfaces ; as examples of this the Raven
and the Carrion Crow may be cited ; all the feathers of these
species found to be barred were iridescent, and no markings were
found on non-iridescent feathers. At one end of the scale we
have such birds as Nightjars and Owls, on the plumage of which
bars are difficult to find, and at the other end such birds as
the Glossy Ibis and swans, where too many parts of the plumage