212 THE ZOOLOGIST. 
Whinchat. Amongst Australian birds, are those of the natu- 
ralised Indian or Ceylon Mynah, the Coach-whip bird, and the 
Wedge-bill, and the species of Zosterops, a small family allied to 
the Honey-eaters. Such examples, it is to be noted, are ex- 
tremely scarce. It is difficult to surmise the causes which can 
have combined to produce this unique coloration. If the 
‘‘motive”” be protection, it must fall under the general principle 
that intruders are shy of the brightly coloured objects. Some 
support for this view may be derived from Mr. Bates’ well- 
known observations on deterrent colours amongst insects. It is 
difficult, moreover, to discover a blue in the surroundings of the 
birds, which could produce so pronounced a mental conception 
of this colour. It may be the blue of the butterflies on which 
they feed. It may be the blue of the aérial vault above. It 
would seem, if this second suggestion be the right one, that very 
few indeed of the birds have their attention attracted strongly 
by the azure of the skies, while they occupy their aérial homes. 
The eggs of the Ostrich vie in colour with the pale yellow 
sand of the African desert, in which they are buried for the sake 
of incubation by the sun’s heat*; but those of the Emu, laid in 
the Australian bush, are, as every one knows, dark green. Here 
we have an indication that the Australian bush is not made up 
of yellow sandy deserts. The Emu, in fact, scoops out a hole 
in the ground amongst low scrub, and contemplates eucalypts 
and salt-bush, and other dull vegetation. Its eggs are exposed, 
and protected by their colour. The Cassowary, laying and 
living amongst the bright green of the tropical grasses and the 
vivid green of a more diversified tropical foliage, produces 
lighter and brighter green eggs. 
With the birds of prey the mental perception of habitual 
surroundings seems to have been intense (as might have been 
expected from their known keenness of vision), and the influence 
upon the colouring of the eggs remarkable. The nests of the 
Eagles, Falcons, and Hawks are large, and exposed on the tops 
of trees or on the ledges of lofty cliffs. The eggs are generally 
more or less blotched with rusty red, presenting a marked 
resemblance to old blood spots, such as the family are so well 
acquainted with. The Nankeen Kestrel breeds in spouts of 

* This is a misapprehension. The process of hatching is performed by the 
male and female sitting alternately. See ‘ Nature,’ 22nd March, 1883,—Ep, 
