APPENDIX. 421 



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 be- 

 ing mentioned, only when the best means of identification. 

 On observing a bird for the purposes of this Key, note the gen- 

 eral coloration (as in the Downy Woodpecker, 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 

 coloration of the tail beneath. Eggs plainly colored belong to 

 I ; eggs which are marked (not stained) to II. In the 

 former, the uniform color (as white) leads to the sections let- 

 tered 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 continuous!}'. 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 parenthesis 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. 

 Occasional^, as is 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 

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



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

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

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

 to be to those of the Key. The former are in Arabic, the other 

 in Roman, numerals. On reaching the Key-section referred to, 

 find (if it is divided) the right division marked with a capital 



