Further Notes on the Crossbill.



117



The study of migration is luckily being more seriously

undertaken at the present time than has hitherto been the case,

and we may hope that when the details of this irruption, which

included a large part of the Continent as well as England, have

been carefully worked out, we may be a step nearer to fathoming

the origin and cause of the migratory instinct.


The different plumages of the male, female and young are

well shown in the plate, but much yet remains to be discovered.

According to Layard, writing many years ago, the males first

assume a greenish yellow dress, and, subsequently, the better

known red livery. When working at the subject a few years back

I came, from a careful study of skins, to the same conclusion

as Layard, viz., that normally the first winter plumage is greenish

yellow, and that they frequently breed while in this plumage in

their first year. At the same time (I quote from my notes) ‘ there

is no doubt that they become red to a certain extent during their

first year.’ Very old birds lose the red aud become golden

yellow. Unfortunately these birds always become yellow in

confinement so that we are unable to test the matter in this

direction. The female is always of a dull green, and the young

are greenish with darker stripes on the breast and back.


Great differences are shown in the thickness and depth of

the bill, those with the larger bills being known as Parrot Cross¬

bills, these may quite possibly represent a distinct race, but the

matter is still a debateable one. The Scotch Crossbill has re¬

cently been differentiated from the Continental birds by Dr.

Hartert, and it apparently shows certain definite minor differ¬

ences ; but, in view of these irruptions occurring from time to

time, it is difficult to understand how the differences can have

arisen or remained pure, and it would have been interesting and

instructive if the matter of the cross-breeding of the races had

been investigated last year, which we fear was not done.


We trust that these notes may attract the attention of some

of our readers to this most delightful bird, and that they may be

tempted to try and fill in some of the uncertainties which still

exist in regard to its habits, plumage and movements.



