INTRODUCTION. 157 



but is uttered so inwardly, that it is almost necessary 

 to stand beneath the tree upon which the bird is 

 perched, before its notes can be heard/'* 



In their habits, so far as we are acquainted with 

 them, they are active and almost restless. The 

 forms of the Old World constantly flit from shrub 

 to shrub, and from flower to flower, in search of 

 food, which, by nearly all our writers, has been de- 

 scribed to be the sweet juices found in the bottom 

 of the corolla or in the nectaries, or the sweet sap 

 which several trees naturally give out; at seasons 

 only, when these materials were wanting, repairing 

 to the search of minute insects ; in searching thus, 

 they never employ the hovering flight of the Hum- 

 ming-birds, but clamber and suspend themselves by 

 the trunks or branches in the manner most conve- 

 nient to gain access to the, in many instances, 

 lengthened corolla, and in their general activity 

 now show a close resemblance to the Titmice, or 

 scansorial warblers of America. The form of the 

 bill and lengthened tongue are both adapted for be- 

 ing plunged into the tubes of flowers ; but another 

 structure in the bill induces us to believe that they 

 (Nectarinia) are more insectivorous at all times than 

 what has been generally considered. We mean the 

 minutely and regularly dentated margins of the 

 mandibles, so delicate as not to be perceptible with- 

 out the aid of a magnifier. Now, we never find 

 this structure where some prey is not to be seized 

 and held. Among some of the Humming-birds it 

 * Gould, Birds of Australia. 



