36 NATUEE AND SPORT IN SOUTH AFRICA 



colouring, and the hoarse " glock, glock!'' which they 

 uttered as they came up and swept round the pool. 

 The Namaqua and variegated sand-grouse average 

 about 9 J in. to 10 in. in length ; the double-banded 

 is about an inch longer ; while the yellow-throated 

 is again a bigger and heavier bird of about a foot in 

 length. The Namaqua and variegated sand-grouse 

 mingled together freely as they came up, and circled 

 incessantly round about the water at an immense 

 rate of speed. Suddenly a combined band would 

 swerve towards that end of the pool farthest from 

 our wagons, and with one swoop of incredible 

 swiftness descend upon the margin of the water. 

 The loud rustle of their wings, as this manoeuvre 

 was enacted, was most remarkable. If not dis- 

 turbed, the leading birds drank quickly and flew off, 

 when others took their places ; the watering process 

 being gone through with perfect order and without 

 over-crowding. If, however, my companion or I 

 moved Avith our guns in that direction, the whole 

 flight would rise with a loud whirr of hundreds of 

 pairs of wings, and circle high in the air again about 

 the pool, until a safer opportunity presented itself 

 for drinking. The great yellow-throated sand-grouse 

 held together in flocks of from a dozen to thirty or 

 forty. They stooped together at the water and drank 

 frequently. From eight o'clock till close on ten this 

 wonderful flight continued ; as birds drank and de- 

 parted, others were constantly arriving to take their 



