The Oologist. 



VOL. XV. NO. 5. 



ALBION, N. Y., MAY, 1898. 



Whole No. 144 



The Coloration of Eg-g-s. 



CHARLES L. PHILLIPS, TAUNTON, MASS. 



Oology if properly followed as a study 

 is a very laudable and instructive 

 science. Too many collectors, how- 

 ever, do not have a proper regard for 

 birds, nor do they really make a true 

 study of oology. They simply have a 

 liking for the freedom and spirit of ad- 

 venture felt while e.xploring the woods 

 and fields for the nests and eggs of 

 birds, and a certain elation in amassing 

 a large collection, and perhaps procur- 

 ing specimens which some fellow col- 

 lector has been unable to obtain. In 

 other words, rivalry often exists among 

 the young oologists of a neighborhood, 

 and in trying to outdo each other they 

 seem to lose sight of the primary object 

 of their chosen science. It is not only 

 advisable to become familiar with the 

 birds themselves, their habits, songs, 

 niditication, and in fact the general 

 features taught in the ordinary book 

 treating of the ornithology of a given 

 section of country, but it is best to 

 learn these things and at the same time 

 to pi'obe deeper into the science which 

 we are considering. To assist the 

 readers of The 0<)Logist in the way 

 soggested is the object of this article. 



As we glance over a large collection 

 of eggs we are usually impressed with 

 the variety and beauties of the colora- 

 tions. Hardly a shade of color known 

 to the experienced artist is absent, and 

 the charming combinations of tints are 

 tastefully blended and often much en- 

 hanced by a glossy surface, while again 

 some specimens have their markings 

 made more pleasing to the eye Ijy the 

 ilullness of the shell which seems to 

 give the colors a velvety appearance. 



This is especially noticeable among the 

 browns and neutral tints. There ai'e 

 some eggs which owing to the absence 

 of markings and I he rough chalky ex- 

 terior cannot be called pretty, but they 

 are intei'esticg, neveitheless, and they 

 must not be omitted from the collec- 

 tion. These plain eggs offer contrast 

 to the colors and they are just as valu- 

 able to the lover of oology as the most 

 richly marked specimen in the cabinet. 

 The primary colors or pigments used 

 by nature in decorating the eggs of 

 birds have by spectrum-analysis been 

 divided into seven distinct substances 

 to the admixture of which in certain 

 pi'oportions all known tints are due. 

 These coloring substances, which bear 

 rather long scientific appellations, are 

 seemingly blood and bile secretions 

 made upon the surface of the egg as it 

 passes through the oviduct. Primarily 

 the spots are doubtless nearly circular 

 in form, but the motion of the egg 

 causes mostof them to become fmeared, 

 prolonged, or otherwise distoi ted from 

 the original form. The pale, obscure 

 tints are evidently first deposited and 

 so become deeply seated, rubbed off in 

 part, and perhaps slightly covered with 

 the lime like substance of the shell. 

 The bright marks are those deposited 

 just before the exclusion of the egg. If 

 they be rouijd the egg was moving 

 slowly or possibly not at all, or if they 

 be prolonged into streaks the egg was 

 evidently progressing quite rapidly, 

 and these marks sometimes show that 

 the egg was slowly revolving during its 

 passage." The ground tint which uni- 

 formly covers the whole egg of certain 

 species is probably laid on before the 

 egg begins its motion. It is well-known 

 that some families, the hawks' for in- 

 stance, lay, as a rule, one or more eggs 



