156 EGGS OF BIRDS. 



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 f 

 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 



