1 6 EVOLUTION OF BIRD-SONG 



wryneck, and the blue titmouse, utter a hiss not 

 unlike that of a snake — a circumstance well known 

 to egg- collectors. The brooding domestic duck 

 hisses at the hand which attempts to remove her 

 eggs ; and, under the same conditions, the common 

 domestic hen makes a violent puffing, less harsh 

 in tone, but otherwise greatly similar to the hissing 

 of the duck.-^ The great owl {Bubo maximus\ when 

 angry, utters a sharp, loud hiss, not unlike the 

 sound produced by the common brown owl of 

 England when irritated. I have only observed 

 one great owl, a bird two years old, in very com- 

 fortable quarters near Stroud. The young hoopoes, 

 when disturbed on the nest, " crowd forward and 

 utter a hissing noise " (Harting, Stmimer Migrants, p. 

 255). The gander, too, hisses as a means of menace 

 to any one threatening his goslings (Jesse, Gleanings, 

 p. 48). The mute swan hisses loudly at intruders 

 when his mate is on the nest. The nestling young 

 of the common pigeon and those of the turtle-dove 

 {C. tu7'tur) make a blowing or puffing sound as a 

 menace. The common rosy cockatoo employs a 

 short, sharp puff for the expression of anger ; and I 

 heard a precisely similar sound uttered by two fresh- 



^ A few years ago, in May, I saw at the Zoological Gardens in 

 Regent's Park, London, a ruddy shelduck chasing a gull around his 

 pond. The shelduck was hissing violently. 



