GRASSHOPPER WARBLER 88 



the old birds return year after year to the same breeding-place, but 

 that the young also come back to the spot where they were hatched ; 

 also, it appears to show that in this frail and far-travelling species 

 the annual increase is only sufficient to make good the losses from 

 all natural causes. 



Immediately after their arrival in April the males begin their 

 curious vocal performance, at first with a feeble and broken strain ; 

 but in a little while the voice gains in strength and shrillness, and 

 the utterance becomes more sustained, lasting sometimes without a 

 break for thirty or forty seconds, and even longer. This is renewed 

 again and again at short intervals throughout the day, and continued 

 far into the night. Indeed, the song may be heard all night long 

 in fine summer weather. The sound is recognised by few of 

 those who hear it as coming from a bird. It is usually attributed 

 to an insect, and if the hearer grows curious, and tries to find the 

 exact spot from which it issues, he finds this a somewhat difficult task. 

 The sound seems now on this side, now on that, now far away, and 

 anon close at hand ; it is here, there, and everywhere. A good plan 

 is to put the open hands behind the ear, then to turn slowly round 

 until the exact spot is discovered. When the bush from which it 

 proceeds has been found, the listener should advance cautiously to 

 within a few yards of it, and sit down and wait until the hidden 

 bird, recovering from his alarm, comes up to the summit and re- 

 sumes his singing. It is then most interesting to observe him. The 

 bird sits motionless, turning its head from side to side, and so long 

 as the strain continues the yellow mouth is wide open, like the 

 gaping mouth of a fledgeling waiting to receive food, the slender 

 body trembling with the sound, as if an electric current were passing 

 through it. The sound produced has been compared by different 

 writers to the song of a grasshopper, only more sustained ; to the 

 cicada ; to the whirring of a wool-spinner's reel, and to that of a 

 well-oiled fisherman's reel made to run at a very rapid rate ; and, 

 finally, to the sharp, vibrating sound of the rattlesnake, and to an 

 electric bell ; but it is not so sharp as these last two. 



The grasshopper warbler builds on the ground, and so well con- 

 cealed is the nest that it is only possible to find it by watching the 

 birds when carrying nesting materials into the bush. The nest is 

 formed of dry grass and moss, and lined with fine fibres. Five to 

 seven eggs are laid, white or pale pink, spotted with reddish brown 

 over the entire egg; and sometimes fine hairlike lines are mixed 

 with the spots. 



