1J00K. 
This species appears not unfrequently to exhibit curious malformations of the beat. I have on two occasions 
seen birds flying past with elongated or twisted mandibles ; and on shooting one in Glenlyon, in Perthshire, 
I discovered that the beak was curved downwards, and much resembled that of a Chough, only far thicker and 
at least an inch longer. It was apparently a bird of the year, still retaining the feathers over the bill. 
The adult llook ( as a11 observers must be well aware) exhibits a patch of scurfy skin over and round the 
sides of the bill ; this bare space appears at a short distance of a dirty white tint. In the youm- bird 
immediately after leaving the nest, this space is covered with black feathers or bristles. It is usually allowed 
that this sign of immaturity disappears after the first moult, when the young bird is supposed to become 
similar in appearance to the adult. I am of opinion that still further attention will have to be given to this 
subject be lore the truth is arrived at. The eye of the young bird on leaving the nest is of a dull slate tint and 
differs considerably from that of the adult, which is a dark hazel. After a few weeks the iris changes and 
assumes the same colour as in the mature bird. I mention tl.is fact, as it appears to have escaped the notice 
of all writers. 
lhc old-fashioned idea that the absence of feathers was caused by the bird thrusting its bill into the 
ground, while digging for worms and grubs, has, I believe, long been proved a fallacy. The bare scurfy skin 
round the base of the mandibles is evidently the natural state, though the date at which it is assumed may 
possibly be doubtful, should there be any foundation for the theory of those writers who assert that observations 
made on birds in captivity arc not to be relied upon *. 
In the adult the colour of the interior of the mouth and tongue is a dull slate, while in the young 
immediately after leaving the nest it is of a deep red flesh tint. I have repeatedly reared Rooks from the nest to 
ascertain at what age the bristles were thrown off and the slate tint of the mouth assumed. Little or no 
difference was detected in any case that was carefully watched. The following is the result of observations on a 
young bird taken from the nest in May 1882. The colour of the interior of the mouth commenced to change 
about the end of the first year, when the bird was probably nine months old. The tongue and the interior of 
the mandibles first showed the slate tint, which gradually spread over the roof of the mouth (detached spots 
appearing in the first instance) and finally reached the throat. The gullet, at all ages, is of a dark flesh tint. 
This change in colour was accomplished in about three months, the mouth being thoroughly slate-tinted by the 
time the bird was a year old. Towards the end of April 1883, a few of the bristles under the beak were lost ; 
none of those on the upper mandible had, however, as yet disappeared. During the first and second weeks in 
May, small bare patches showed on the upper mandible, though the whole surface did not exhibit the usual 
white scurfy appearance of the adult till well on in July. It was not till the middle of August that the last 
signs of the bristles had completely vanished. 
The statement that young birds lose the feathers over the base of tbe beak at tbe first moult can scarcely 
be correct, or there must be not unfrequent exceptions to the rule. Not a single specimen that I have had the 
opportunity of examining in captivity has changed at that age ; and during the earlier months of the year 1 
have at various times met with specimens exhibiting tbe black feathers over the bill. 
Being anxious to gain information concerning tbe number of Rooks showing black beaks in Sussex 
during spring, I closely examined every party met with on the downs in April 1882. Though some 
thousands of birds were carefully inspected, I could only positively identify three specimens in this stage. 
On April 2nd a bird on wing skimmed past so close that the feathers and bristles were visible to the naked 
eye. On the Cth I remarked another in tbe same state. This bird repeatedly flew after an adult searching 
for food on the downs ; and although it did not flutter its wings in the manner of the young when first taking 
after their parents, it gave the impression it was following the old bird for what it could get. Nothing, 
* Acc0rdm o to my own experience, tho changes undergone by birds reared in captivity corresponded, in every instance where I have been 
able to verify the fact, with those in a natural state. 
