Mimicry in Birds BIT 
Moreover, all round the 
world in warm climates are 
found the hawks of the genus 
Elanus, which in their delicate 
grey plumage, long narrow 
wings, and lazy flight most 
remarkably resemble gulls and 
terns. Mr. W. H. Hudson, 
in his delightful book ‘The 
Naturaliss im la Plata,’ 
mentions the resemblance of 
the Hlanus to a gull, and 
says that the birds seem less 
afraid of it than of other 
hawks. And in India the 
species of Hlanuws found there 
(H. cerulews) is called by the 
natives “Jungle Tern”; I have seen it myself and taken it for a tern at first sight, so 
similar is the colour to that water-bird’s, and so different the slow swing of the pinions 
from the sharp decisive stroke one associates with the flight of most hawks. 
As every falconer knows that half the battle is to get the hawk near enough to 
the quarry to prevent the latter having a long start, it seems very obvious that these 
deceptive birds of prey profit by their resemblance to more or less innocent species 
Just as much as, in another way, appear to do the birds mentioned above as 
resembling creatures less liable to attack than the majority of birds. 
As to the method by which these remarkable likenesses have been produced, I 
cannot agree with the theory current with regard to the similar cases in insects, that 
the resemblance of the mimic to its model was only slight at first, and was gradually 
perfected by the escape from destruction of those specimens which exhibited it in 
the greatest degree, until, by the continual preservation of such and their descendants, 
the resemblance was, so to speak, bred imto the mimicking species. This seems to 
me to require too many mistakes on the part of the other creatures concerned, and 
I much prefer Darwin’s view, that mimicry must have commenced between forms 
pretty much alike to start with, so that natural selection was only needed for the 
finishing touches. Thus it may be doubted whether, in the case of birds, the 
resemblances, though probably useful enough now, were not altogether accidental to 
start with, for there are just as many startling resemblances where no theory of 
mimicry will suttice; the birds do not even live in the same country im many cases. 
Thus, as Sir Walter Buller and Mr. F. KE. Beddard have pointed out, the one in 
his work on the “Birds of New Zealand” and the other in “ Animal Colouration,” the 
large’ cuckoo of New Zealand (Urodynamis taitensis) 1s mdeed very lke a hawk, but 
the species it most resembles is not a New Zealand one, but Cooper's Hawk of 
North America (Accipiter cooperi)! And it may be added that our own cuckoo more 
resembles some of the tropical hawks of the genus Baza than any British hawk. 
Several kinds of Baza have the plain grey breast of the cuckoo, and they are even 
called “cuckoo-falcons” from their resemblance to that bird, while the English sparrow- 
hawk is barred on the breast; the barrmg on the cuckoo not reaching up so high, 
which renders its likeness to that hawk decidedly imperfect. 
The Great Skuas (Megalestris) show a singular resemblance to birds of prey in 
their dark-brown plumage streaked with tawny on the neck, which recalls that of 
many eagles, while the white patch at the base of the primary quills reproduces the 
BOURU ORIOLE. 
