8 BRITISH BIRDS, THEIR EGGS AND NESTS. 



it is unnecessary, if not inexpedient, to direct the young collector's 

 attention; in any other way, at least, than as to a matter of 

 curious observation and contrast. As a means of identification it 

 fails completely, and is only adverted to here for the purpose of 

 obviating a portion of the perplexity which may often occur in 

 practice to the youthful egg-fancier from the difference in size 

 between different specimens of what are in reality eggs of the 

 same species of birds, but seem to him, from their discrepancy 

 of dimensions not possibly so. 



Again, the colour and markings of many different species of 

 eggs are found to admit of great variation. The most familiar 

 and striking instance is in the case of the Guillemot: but one 

 more within the reac h of every nest-hunter is presented by the 

 eggs of the Blackbird. Sometimes the spots on them are very 

 minute and multitudinous ; almost confluent from their number 

 and minuteness ; sometimes large and well defined and permitting 

 the ground-shade of the shell to be very apparent ; sometimes 

 reddish in colour, closely approaching the shade of those on the 

 Ring-ousel's egg, and sometimes brown in hue, with no reddish 

 tinge at all ; and sometimes they disappear altogether, or very 

 nearly, and leave the egg with a strong resemblance to the little- 

 spotted Thrush's egg. * To such an extent is this the case, that 

 a year or two since I was misled into assuming that four eggs 

 which I found in a nest with all the characters of a Blackbirds 

 nest, must most certainly from their colour and markings, be as- 

 signed to a Thrush original and not to a Blackbird. Other familiar 

 instances of the same kind may be noticed as met with in 

 the eggs of the House-sparrow, the Tree-pipit, the Sky-lark, 

 the Yellow-hammer, one or more of the Hawks, &c. 



In the fabric and materials of nests, again, as constructed by 

 birds of the same species, much dissimilarity, under peculiar 

 circumstances, will be found to prevail. But really not more 

 than might have been looked for beforehand, if it were not that, 

 in our usual way of thinking about birds and other animals, 

 we lay so muc] stress upon Instinct, and do not so much as 

 admit to our notice the possibility that, many of their actions 

 may be prompted by a measure of intelligence, and not simply 

 an unconsidering, unreasoning influence, which we term their 

 Instinctive endowment. No" doubt Instinct teaches them both 

 to build and how to build their nests, and what materials are the 

 most suitable, and the sites that are most eligible. But it is 

 scarcely Instinct which sets the Eagle and the Crow, when their 

 abode is in a place that does not furnish the sticks they commonly 

 or instinctively use for building their nests, to adopt instead of 



* Yarrell, i. 204. Hewitson, i. 63, 



