18 INTRODUCTION. 



If inexperienced, do not make exchanges with another inex- 

 perienced person, who may unintentionally cheat you, or with 

 one unknown to you, who may purposely cheat j'ou. Remember 

 that eggs often var}' greatly in value in different parts of the 

 country, and do not accept any price-list as a basis for ex- 

 change. Endeavor by energy to arrive at approximate comple- 

 tion, have some definite object in view, such as a cabinet 

 comprising all the eggs of Massachusetts, and do not unwisely 

 form a miscellaneous collection everywhere incomplete. 



§ S. To know the notes of all our birds is a great assistance 

 in finding their nests, and in finding, distinguishing, or study- 

 ing the birds themselves, who sing chiefly on or soon after 

 their arrival from the South, during their migrations, and the 

 mating-season in spring, or early summer. It is best to study 

 their music at sunrise, or in the early morning (particularly in 

 the case of species migrating), and also at evening. Even 

 families may (to a limited extent) be classified by their notes. 

 To study birds, in relation to their habits or notes, walk in their 

 haunts, continuall}' pausing to catch the slightest sound, which, 

 if not recognized, should be traced to its source, or to allow 

 the birds to gather about or approach you. If necessary, 

 follow them silently and persistently, but remember that 

 stealthiness sometimes alarms them more than an open 

 approach. If several species be together, do not be misled by 

 the confusion of their songs, and do not hastily attribute the 

 note of one kind to another bird immediately near. Both 

 squirrels and "chipmonks" frequently produce notes, which 

 might excusably distract the attention of an unpractised orni- 

 thologist. By looking up, especially on very clear days, you 

 may often see hawks, or other birds, flying over silently. 



