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shortness of its tarsi, to be actually lying on its breast ; but it seldom remains long in this position, 
being far more restless than the other species. Eising silently, it mounts in the air, and having 
marked out a fishing-ground, hovers first to one end of it and then to the other, repeating the circuit 
with the most regular precision. It is less sociable than the other Terns, never assembling in flocks, 
but always associating in pairs, usually hunting together in silence but with an occasional call-note, 
sounding like creJc-crelc. Sometimes four are seen in company, but this only represents a family 
party, the additional members being the young birds of the year. 
During the breeding-season it is very clamorous, especially when its nesting-ground is invaded 
or even approached. It deposits its eggs on the bare shingle, without any attempt at forming a nest, 
merely selecting a natural depression suited to its own size j and the colour of the eggs harmonizes 
in a remarkable manner with their surroundings. 
There is nothing more interesting in the study of oology than the systematic way in which the 
colouring of eggs (and particularly those of sea-birds) is adapted to their natural environment. 
Captain Mair has furnished me with a remarkable instance of this law of assimilative colouring 
for protective purposes. In December, 1876, he visited the Eurima Eocks, in the Bay of Plenty, 
and found large numbers of Larus scopulinus breeding there. In some localities the nests — ■ 
roughly formed and lined with feathers— were placed in the thick masses of wild spinach or in the 
midst of “ sand-fire.” In all such cases he observed that the eggs which these nests contained were 
splashed over their entire surface with large green blotches, thus assimilating their colour to the 
surrounding vegetation ; whilst other eggs (belonging to the same species), deposited on the white 
sand in the immediate vicinity, had a totally different appearance, being of a light stone-colour, and 
so marked as to harmonize exactly with their sandy surroundings. 
It is difficult, howev^er, to account for the very intricate marking that distinguishes the eggs of 
Larus hulleri from those of its near allies, the breeding-habits of these birds not being, so far as I am 
aware, in any way dissimilar. An egg of the last-named species in my son’s collection is of a creamy 
stone-colour, with a broad irregular inky zone near the larger end, splashed on its edges ^vith umber- 
brown, the rest of its surface marked, in a very eccentric way, with widely-spread hieroglyphics of the 
same dark colour. Possibly these markings are intended to simulate minute fragments of seaweed. 
But assuming this protective resemblance to be a chief factor in determining the natural colours 
and markings on the surface, it is indeed very curious to observe how sometimes the eggs in one nest, 
produced at short intervals and all subject alike to the same conditions as to their future safety, differ 
from one another in their coloration. There can be no doubt that the colouring of birds’ eggs, which 
is chieffy due to animal matter deposited on the surface of the shell and capable of being rubbed or 
scratched off, must be to a large extent influenced by the state of the producer’s health and by any 
special sensations to which the bird may be subjected shortly before the extrusion, for it is w^ell known 
that, even in the case of many birds that produce highly-coloured eggs, the hard shell is found to be 
perfectly white only the day before it is laid. Even Mr. Hewitson, who, in his ‘ Eggs of British Birds ’ 
(Intr. p. viii), declines to admit the general rule that the varied and beautiful hues which adorn the 
eggs of birds are given as a protection against discovery and destruction, is constrained to say : — 
“ That there are several instances in which the eggs of birds are admirably adapted to and closely 
resemble in colour the ground upon which they are deposited, I have frequently found, much to 
my annoyance, when in search of them ; and these are just the instances where such protection is 
most necessary, and where contrasting colours would lead to detection ; such is the case amongst 
those birds which, making little or no nest, deposit their eggs, for the most part, upon the bare 
ground, or the shingle of the sea-beach, and leave them uncovered on the least alarm.” 
This species usually lays two eggs ; these are of a regular oval form, measuring 1-4 inch in length 
by 1-05 in breadth, and are of a yellowish white, the whole surface marked with obscure spots of 
purplish grey. 
