THE NIGHTJAR, OR FERN OWL. 579 
male, and is a really pleasant, purring sound, not unlike 
that of a cat; it somewhat resembles the syllables 
“ errrr” and “eurrrr,” and lasts without interruption 
for at least five or ten minutes at a time; it is produced 
by both expiring and inspiring, exactly as the cat does. 
Careful observation has led to the discovery that “ eurrrr ” 
is produced by the in-drawing of the breath, and “ errrr ” 
by the reverse process. On rare occasions the female 
also may be heard to make a very light purring noise. 
This kind of song is common to many species; I have 
noticed it with almost all the African ones I have met 
with. The Spanish bird, however, emits this sound just 
as little as do the American species, one of which we 
have already been made acquainted with under the name 
of its call, “ Whip-poor-Will.’’ 
I cannot but regard the whirring tones of the Goat¬ 
sucker as a most delightful nocturnal serenade; whenever 
I hear them—even now—they carry my memory back to 
days gone by, when—passing the night in some African 
forest or desert village, all around lay buried in profound 
rest, uninterrupted, save by the occasional howl of the 
hyaena or the jackal; perhaps also the cry of the 
leopard or dull roar of the lion giving evidence of their 
watchfulness—I would hear the droning of the Goat¬ 
suckers, who, gliding amongst the huts, and perching on 
the neighbouring bushes, unmindful of either myself or 
beast of prey, would purr away without ceasing, their 
song of satisfaction: when one left off another began ; 
and so it went on. One night in particular I well 
remember, when I had lost my way, and was forced to 
bivouac in the open forest, surrounded by howling 
hyaenas,—prevented by the high wind from even lighting 
a fire, and having to calm my terrified camel,—I saw 
4 H 
