APPENDIX. 443 



C. D. THE USE OF THE KEYS. 



IT is impossible, so far as is known, positively to identify many 

 eggs, without some knowledge of the nest and parent-birds. In the 

 following "Key to the Eggs of Massachusetts" (C), the position, 

 and sometimes the structure, of the nest is the chief point dwelt 

 upon ; the colors of the parent-birds being mentioned only when the 

 best means of identification. On observing a bird for the purposes 

 of this Key, note the general coloration (as in the Downy Wood- 

 pecker, black and white), particularly above, the color of the breast, 

 whether streaked (spotted) or not, the color of the crown and 

 throat, or of the entire head, and the color of the tail, whether the 

 outer feathers are white or not (best observed as the bird flies). 

 Observe any prominent markings, and, in large Hawks, the colora- 

 tion of the tail beneath. Eggs plainly colored belong to I ; eggs 

 which are marked (not stained) to II. In the former, the uni- 

 form color (as white) leads to the sections lettered A, B, C. In the 

 latter, the ground-color leads to similar divisions. The subsections, 

 (a), etc., are arranged according to the position of the nest. Under 

 each subsection, the list-numbers run continuously. Glance down 

 the column of the next figures (the extreme length and breadth of 

 the eggs expressed in hundredths of an inch), until you find a size 

 apparently corresponding to that of the egg in hand. If there are 

 several eggs together in the Key of nearly the same size, read 

 across the page until the right description is reached. You will 

 often find some characteristic or means of distinction in the names 

 of the birds. The figures at the end refer to the main work. List- 

 numbers (to the extreme left) in parentheses indicate rarity of the 

 corresponding nest in Massachusetts, or at least rarity under the 

 circumstances mentioned. > means more than ; < means less 

 than. Before two numbers connected by a cross (X)> these signs 

 affect both. $ means male ; 9 means female. Occasionally, as 

 in the case with the Bald Eagles, birds breed before attaining their 

 full dress. 



The " Key to the Land-birds of New England " (D) has been 

 arranged as much by the coloration of birds as possible, but it can- 

 not be used without having the bird in question at hand. 



On the first page, follow the lines of the table, and also the divi- 

 sions (beginning at the right), until a reference is reached. These 

 references are to sections of the main work, unless stated to be 



