16 FEATHERS. 



tube remains bedded in the skin, bat is generally detached with- 

 out difficulty, and at a certain period falls to give place to a new- 

 feather. This renewing of the feathers, which is called moulting, 

 occurs, in general, every year after the season of laying, and 

 sometimes it takes place twice in the year, in the spring and the 

 autumn ; it happens earlier in the old than in the young, and is 

 a period of indisposition during which the bird usually loses its 

 voice. 



17. The form of these tegumentary appendages varies much ; 

 some are destitute of beards and resemble the spines of the por- 

 cupine ; others have stiff beards which are armed with smaller 

 beards which hook into each other, so as to form a great tissue or 

 coat, which the air does not penetrate ; others again have the 

 beards and the smaller beards (barbs and barbules)long, flexible, 

 and not hooked into each other, which renders them extremely 

 soft and light ; and there are some which resemble simple down. 

 Their colours are infinitely varied and often surpass the most 

 beautiful flowers or the most brilliant gems in beauty and splen- 

 dour. Generally, the plumage of the female is not so rich as that 

 of the male, and it is rare for the young bird to be clothed in the 

 same colours that it will wear all its life ; they often change two 

 or three years afterwards, and sometimes the adult wears a 

 plumage in the spring, altogether different from that of winter.] 



18. The large stiff feathers that grow on the anterior extremi- 

 ties of birds, which are called wing feathers, or pinion feathers, 

 expand these organs very considerably without increasing then: 

 weight, and convert them into powerful oars destined to cleave the 

 air, and strike against it with so much force and frequency, that 

 the shock thus produced impels the body of the animal in a con- 

 trary direction. The ability of the bird to sustain itself in the 

 air, and move with rapidity, is in proportion to the expanse of the 

 wings. The feathers which contribute most to the extent of 

 the wings, and that are most useful in flight, are those which are 

 attached to the hand, and, consequently, most distant from the 

 body ; they are always ten in number, and are called primary 

 renriyes; the feathers of the fore-arm are called secondary remiges; 

 the scaputaiy, which are the least in strength, are attached to the 

 humerus; the bus'ard feathers are those that grow from the thumb, 

 an i the coverts, those feathers which cover the base of the remiges. 



17. Whelhcr does the male or female bird possess the most brilliant colours? 

 Are the colours of all birds the same throughout the year ? 



18. What are the primary remiges? What is their number? What are 

 the secondary remiges? What are the scapulary feathers? What are 

 bastard feathers or quills? 



