28 CATALOGUING AND LABELING. 



tinguished by their color, but the young mule frequently resembles 

 the female, while in some instances the female lias been known to as- 

 sume the plumage of the male. Dissection, therefore, is the only safe 

 way to determine sex. Upon reaching stage 36, in the operation of 

 making a birdskin, cut through the left side of the body from the 

 vent to the neck, taking care not to disturb the internal organs. Force 

 the edges of the opening apart, and, pressing the intestines gently to 



Fio. 1. A completed birdskin. (Reduced). 



one side, look for the sexual organs, which will be found on the walls 

 of the small of the back very near to the backbone. The male organs 

 (testes), two in number, are usually dull-white, elongate bodies lying 

 side by side. The female organs (ovaries) are composed of numerous 

 round bodies lying in a mass or cluster. In the breeding season the 

 sexual organs of birds become much enlarged, and at tins season the 

 testes of a male Chipping Sparrow are about the sixe of a pea, while 

 the ovaries of the female have been likened to a bunch of grapes, the 

 largest being the sixe of the yolk of the egg of this species. After the 

 breeding season the sexual organs decrease in sixe. and in adults in the 

 winter and young birds are sometimes difficult to find. The testes of 

 a male Chipping Sparrow at that season are about as large as a small 

 pinhead, while a hand-lens is required to plainly distinguish the ova- 

 ries of the female. The arrow of Mars ( $ ) is used to indicate the male 

 sex ; the mirror of Venus ( $ ) the female sex. 



Cataloguing and Labeling. Before skinning your birds you should 

 catalogue them. The catalogue should have columns giving (1) the 

 date, (2) your serial collection number, (3) name of the bird. (4) sex, 

 (5) place of capture, (6) name of collector, and (7) remarks. In the last 

 column enter any notes on the color of the eyes, or parts which will 

 change color when drying, contents of the stomach, and other notes. 

 In addition to this "day-book" or "blotter" some ornithologists open 

 a ledger account with their collection, and devote a folio to each spe- 

 cies where are posted the entries made in the collection register. 



Labels should be of strong bond paper, two inches and a half long 

 and half an inch wide. They are attached to the crossed legs of the 

 bird by linen thread strung through their left end. The face of the 

 label bears the name and sex of the_bird, place and date of capture, 



