EGGS OF BIRDS. 
156 
heaths. I execrate the practice as most cruel : their 
death evinces no skill in the gunner ; their wretched 
bodies, when obtained, are useless, being embittered by 
the bruises of the shot, and unskilful operations of the 
picker and dresser. No, let the parental duties cease, 
and when the bird retires to its maritime downs, if 
doomed to suffer, the individual dies alone, and no 
starving broods perish with it. I supplicate from the 
youthful sportsman his consideration for these most 
innocent creatures, the summer wheatear and the 
swallow. 
The eggs produced by the wheatear are uniform in 
color and similar in shape ; but the eggs of birds in 
general vary much, and are occasionally very puzzling 
to identify when detached from their nests, as the color- 
ings and markings differ greatly in the same species, 
and even nest. Those of one color, like this wheatear’s, 
retain it, with only shades of variation ; but when there 
are blotchings or spots, these are at times very dissimi- 
lar, occasioned in great measure probably by the age 
of the bird ; though this cannot account for the differ- 
ence of those in an individual nest. None vary more 
than the eggs of the common sparrow. Those of marine 
birds, especially the guillemot (colymbus troile), are 
often so unlike each other, that it requires considerable 
practice to arrange them. The plumage of birds has 
probably never varied, but remains at this hour what 
it originally was : but whether these markings on the 
eggs have any connexion with the shadings on the 
feathers, it is difficult to determine ; as we know that 
eggs entirely white will produce birds with a variety of 
plumage. The shell of the egg appears to be designed 
for the accomplishment of two purposes. One of the 
offices of this calcareous coating, which consists of car- 
bonate and phosphate of lime, is to unite with the white 
of the egg, and form, during incubation, the feathers 
and bone of the future young ones ; but as a large por- 
tion of this covering remains after the young are pro- 
duced, its other object is to guard from injury the parts 
within. As far as I have observed, in eggs of one hue, 
the coloring matter resides in the calcareous part ; but 
