M. Gloger on the Different Colours of the Eggs of Birds. 99 



and the author, who in his memoir has taken a view of all the 

 birds of Germany, has convinced himself of it.* 



Eggs may be distributed into two seiies, according as their 

 colour is simple or mixed. The simple colours, such as white 

 blue, green, and yellow, are the brightest, and consequently the 

 most dangerous for the egss- 



1. Pure white, the most treacherous of all colours, occurs in 

 the birds which nestle in holes, as the woodpeckers, wrynecks, 

 rollers, bee-eaters, king's-fishers, snow-buntings, robins, water- 

 ouzels, swallows and swifts. It is only in these species that the 

 eggs are of a shining white. 



The eggs are also white in some species which, like the house 

 swallow, certain titmice, the wren, &c., construct nests, whose 

 aperture is so narrow that their enemies cannot see into them. 



White eggs also occur in species which leave them only at 

 night, or at least very little during the day ; of which kind are 

 owls and hawks. 



Lastly, this colour is met with in those which lay only one 

 or two eggs, and which sit upon them immediately after; as 

 pigeons, boobies, and petrels. 



2. The pale green or pale blue colour is found to be peculiar 

 to the eggs of many species which make their nest in holes, as 

 starlings, saxicolae, fly-catchers, &c. 



In the second place, this colour is common to the eggs of 

 birds whose nests are constructed with green moss, or at least 

 placed among grass, but always well concealed ; for example, the 

 hedge-sparrow and blue-throated warbler. 



Lastly, green eggs are met with in several large species capa- 

 ble of defending themselves against the attacks of enemies, such 

 as herons. 



3. A slight green colour is observed upon the eggs of seve- 

 ral gallinaceous birds which lay among grass, without making a 

 regular nest, and which is presently concealed by the great quan- 

 tity of eggs which they lay ; as in the partridge and pheasant. 



• The memoir, entitled " Uber die farbeii der Eier der Vogel von Herr C. 

 Crlogcr," is inserted in Erster Band, 6tes Stuck of the Verhandlungen der 

 Gesel. Naturf. Freunde zu Berlin, 1829. 



g2 



