364 Ornithological Observations and Reflections in Shetland. 
that. the mature Herring Gull were, in colouring,. like theyoung, 
or, at least, had no resemblance whatever, either to the mature 
or young Kittiwake, is it not probable that if would become an 
object of dread to the young birds who thus suffer by it, so 
that they would either avoid it or mob it when it appeared 
amongst them ? They did, in fact, behaye in the first of these 
two ways on the occasion’ when I’ saw one of their number thus 
victimised. It took them indeed’ some time’to realise that 
there was anything’ wrong, but at last they ‘did, and then there 
was a sudden commotion of close-packed scurrying «wings 
outwards, in a circle, from where the tragedy was. enacting— 
a panic, in fact, but.not a very pronounced one, for the birds 
went only,a little way before coming down again on the water. 
Were these attacks made frequently, it would seem surprising 
that even young birds should not be ‘both. quicker to take 
alarm, in each. particular case, and also more generally. dis- 
trustful of the species from whom they thus suffered. But 
I do not:think they are very frequent, and in this circum- 
stance, together with some. degree of resemblance between 
the preyed, upon and preying species; we have two primary 
elements through which a true mimetic resemblance might, 
in time, be brought about: Even:though, in this particular 
instance, the process may not have begun, and may never 
perhaps establish itself, still the facts present us with a possible 
clue to.,‘ the, initial stages” of some of those more or less 
puzzlingly perfect resemblances in nature. which we find it .so 
difficult to account for, but do not perhaps show much im- 
agination or energy in trying to find out. As it appears to 
me, it.is a better plan— that is to say it might. often have 
better results—to fix. our observation on some incomplete 
state of things, and try to reason out: how it might grow into 
completeness,; than to pay attention to culminations only, 
and speculate downwards without much observational search- 
ing to guide us, The beginnings of any striking development 
in nature—the ‘run’ or ‘ bower’ of the Bower Birds, the 
courting display of the Blackcock or Birds of. Paradise, the 
deceptive resemblance between a spider and a bird-dropping, 
or a humble-bee anda fly, parasitic upon it—are of course 
much less striking. and, from that point of view, much less 
interesting, than, what they have ultimately led to. Some- 
where, however, and probably scattered all about, they must 
exist, and in, their discovery lies the sclution of every such 
problem. We should therefore keep constantly endeavouring 
to discover them, and this is best-done by developing an equal 
interest in what is ordinary, which we have so many chances 
of seeing, and what is extraordinary, where the opportunities 
for observation are so much fewer. For once, I believe, where 
the process of a thing may be deduced, it may be seen three 
.. Naturalist, 
