304 Natural-Historical Collections. 
eyes of destructive animals ; whilst, on the contrary, those birds whose eggs are 
of a deep and vivid colour, and consequently very liable to strike the eye, either 
hide their nests in hollow trees, or elsewhere, or de not quit their eggs except at 
night, or commence their incubation immediately after laying. It must, moreover, 
be remarked, that in the species whose nests are exposed, and of which the fe- 
males alone sit on the eggs, without being relieved by the male, these females have 
generally a different colour from that of the male, and more in unison with 
neighbouring objects. 
All-providing nature, says M. Gloger, has thus sought for the preservation of 
the species, whose nests are altogether exposed, by giving to their eggs a colour 
incapable of betraying their presence to a distance, whilst she has been able, 
without inconvenience, to give the most brilliant colours in those circumstances 
where they are hidden from the sight. It would have been more exact, in my 
opinion, says a French writer, if M. Gloger had said, that a certain number of 
birds are able to deposit their eggs in accessible places, because their colours con- 
found them with surrounding things, whilst others have been obliged to conceal 
their eggs, because the marked colours they possess would attract their enemies. 
But however it may be explained, the fact exists; and M. Gloger has accumu- 
lated illustrations with much detail. 
Eggs are to be distributed into two series, according as their colour is simple 
or mixed. The simple colours, such as white, blue, green, yellow, are the most 
vivid, and consequently the most dangerous for eggs. : 
Pure white, the most treacherous of colours, is found in the eggs of birds 
which build in-holes, as the woodpeckers, (Picus), the wrynecks, (Yuna) the 
rollers, (Coracias), the bee-eaters, (Merops), the king-fishers, (Alcedo), the 
snow-finches, (F'ringilla nivalis), the dippers, (Cinclus), the rock and water 
swallows, (Hirundo), and the swifts, (Cypselus). It is of these birds alone that 
the eggs are of a deep white colour. 
The eggs, again, are white in some species which, as the common swallow, 
some titmouses, (Parus), the wren, ( Troglodytes), &c. construct their nests with 
openings so small, that their enemies are unable to see into them. 
Moreover, we find the eggs white in birds which do not quit their nests except 
at night, or at most for a very short time during the day, as the owls, (Sérix), the 
falcons, (Falco). : 
Finally, this colour is found in those which only lay one or two eggs, and 
which immediately begin to sit, as the pigeons, (Columba), the gannets, (Sula), 
the petrels, (Procellaria). 
- As to the clear green or clear blue colour, we find that it is proper to the 
eggs of many species which build in holes, as the starlings, (Stwrnus), the stone- 
chat, (Saxicola), the flycatchers, (Muscicapa), &c. 
In the second place, this colour is common to the eggs of birds whose nests are 
constructed of green moss, or situated in the midst of grass, but always well hid- 
den ; for instance, the hedge-accentors, (Accentor modularis), the blue-throated 
warbler, (Sylvia suecica), &c. 
Lastly, green eggs are found in many powerful birds, able to defend themselves 
against the attacks of robbers, as the herons, (Ardea). 
A faint green colour, approaching to a yellowish tint, is observed in the eggs 
of many gallinacea, which lay in the grass, without preparing a regular nest, 
which soon disappears under the quantity of eggs; thus, the hoopoe, (Upupa), 
the common partridge, (Perdix cinerea), the pheasant, (Phasianus.) 
The same colour is also remarked in many of the palmipedes which cover their 
eggs when they quit them, and which watch them carefully; as the swans, the 
geese, the ducks, (Anas), the. divers, (Colymbus), &c. The eggs of certain 
large birds which build openly in the air, but which are well calculated to defend 
their nests, are of a dusky white, as is observable in the vultures, (Vuléur), the 
eagles, (Falco), the storks, (Ciconia). 
Amongst the eggs of a mixed colour, we must distinguish those which have a 
white ground from those whose ground is of a different tint. The eggs with a 
