Baker (3) and Christensen (14). Whistler (42) quotes Hume as observing 
a group of fully 2,000 birds so closely packed together as to occupy a 
space but 30 yards long by 10 yard wide. In our experience these are 
exceptional for we found parties of a few to several hundred birds to 
be the general rule on wintering grounds in the Iberian peninsula and in 
the Middle East. The illusion of larger flocks often is created by 
noting a constant stream of birds coming to and leaving the watering 
places without realizing that these aggregations subsequently tend to 
break up into much smaller groups. 
This is particularly true on the breeding grounds in Turkey and 
Iran where, early in the morning, one could observe pairs or’ small parties 
of birds collecting into larger flocks on their way to Hie gue breaking 
up again upon leaving these waterholes. On the open Anatolian plains 
pairs or flocks of up to a few dozen birds were the rule from April 
through October. 
Psychology and Behavior 
Imperial sandgrouse are gregarious, rather even-tempered and are not 
pugnacious. Pair or flock responses are the normal even in captivity. 
In Turkey, chukars, black francolins, and Turkish gray partridge (Perdix p. 
canescens) were penned together with imperial sandgrouse without difficulty 
except for the occasional bowling over of the slower-moving sandgrouse by 
other birds when frightened. Common Indian sandgrouse and imperials 
penned together in India reacted almost as though they were the same species. 
Both groups were surprisingly placid in captivity until frightened by the 
biologist in the course of providing food and water. On such occasions 
the entire group would spring straight upwards into the air, calling 
repeatedly and flying about. Momentum lost, they then fluttered to the 
soft sand floor where they immediately regained their composure. Freshly 
penned sandgrouse, when confined in a screened pen lined with cheesecloth, 
were observed to doze, dust, preen their feathers, eat, and drink with 
little signs of fear. 
Calls 
Most sandgrouse have distinctive, almost ventriloquistic call notes. 
These vary but little and are constantly uttered in flight. Though not 
loud they carry so well that it is normal to detect the approach of a 
flock of imperial sandgrouse by hearing a fairly loud, clucking, .musical 
"churr-churr-rur-rur" considerably in advance of locating them in the air. 
Birds on the ground will call occasionally to a passing flock; otherwise 
they are silent. 
Interbreeding 
Present records do not indicate any crossing of the imperial sand- 
grouse with other species of sandgrouse even though the ranges of 
several species overlap. 
57 
