THE HOOPOE. 257 



the syllables " hoop-hoop," "hoop-hoop/* fre- 

 quently repeated, and in the quality of its tone 

 approximates to the call of the Cuckoo, but the 

 second note is a repetition of the first instead of 

 being, as in the case of the Cuckoo, a third 

 below it. Old authors affirmed that this pecu- 

 liar sound was produced by the bird distending 

 its cheeks with air, and tapping its bill upon the 

 ground, thereby causing the notes to escape as 

 it were spasmodically. This curious statement 

 has received some confirmation from the obser- 

 vations of Mr. Swinhoe. 1 He says : " To pro- 

 duce these notes, the bird draws the air into its 

 trachea, which puffs out on either side of the 

 neck, and the end of the bill is tapped perpendi- 

 cularly against a stone or the trunk of a tree, 

 when the breath being forced down the tubular 

 bill produces the correct sound." He adds, 

 however, that he has observed a Hoopoe 

 perched upon a hanging rope, and uttering its 

 well-known cry without any tapping of the bill. 



1 Cf. "Zoologist," 1858, and "Proc. Zool. Soc.," 1863, 

 p. 264. 



