32 



FORM AND HABIT: THE BILL. 



corolla. Ill the Tootli-ljilled Hummer (Androdon) both 

 mandibles are lincly seiTate at the end, the upper one 

 lieing also hooked, and the bird feeds on insects which it 

 captures on the surface of leaves and other places. 



Among the Woodhewers {Dendrucolaptldw) of South 

 America there is fully as much vaiiability, which reflects 



equally variable feeding 

 habits. Some species have 

 short, stout, straight bills, 

 others exceedingly long, 

 slender, curved ones. 

 Mergansers, Gannets, An- 

 hingas, and other birds 

 that catch fish by pursuing them under water, have 

 sharply serrate mandibles, which aid them in holding 

 their slippery prey. 



Some shore birds (Limicolre) use the bill as a probe, 



Fig. 18. — Serrate bill of Mcri^^anser, a fish- 

 eatiug bird. ^1/2 natural size.) 



Fig. 19. — Probelike bill of Woodcock, showing extent to wliieli upper luainli- 

 ble can be moved. ( 2/3 natural size.j 



when it may be six inches in length and straight, or 

 curved downward. It has recentlv been learned that 



Fig. 20, — nccm-vcil Inll of Avoeet. (2/3 natural size.) 



several of these probing Snipe, notably the AVoodcock, 

 have the power of moving the end of the upper mandi- 



