ranged from 1.05 to 3.14 km (average 2.35 km). Two types of display 
were observed: firstly in small circles, always at the same location, and 
alternating with long periods when the males stood still, with the neck 
feathers erected. The second type was a running display over hun- 
dreds of meters. The spatial distribution of the males, the two types of 
displays and the fact that aggressive behaviour between males was 
common at the beginning of the breeding season becoming rarer as the 
study period wore on (E. Mukhina pers.comm.) suggests that males 
establish territories soon after arriving on the breeding grounds. The 
latter display may be performed by non-territorial males or by males 
attempting to establish a territory. 
Observations of females were rare (70% of all observations were of 
males). One incubating female, two single females and two females 
with three chicks were observed (map 1). Two nests, 7.49km apart, 
were found (map 1). The distance between one of the nests and the 
nearest displaying males was 0.74km. In Kazakhstan (Tau Kum 
region) the distance between a nest and the nearest displaying male 
was 1.48km. Nests are thought to be located in the same area every 
year (B. Gubin pers.comm.) and are usually found from late March or 
early April onwards in Uzbekistan. Females finish laying at the end of 
May although females with chicks are present for another two to three 
months. At the end of the egg laying period males also cease display- 
ing and start to form small parties before migrating. In Turkmenistan 
it is thought that breeding birds depart by May, whilst the young birds 
remain. Small groups (three to eight individuals, mostly males) also 
occurred on the breeding ground. These groups were usually seen 
only once. During the breeding season some birds may be constantly 
on the move. It is not yet known if such groups are composed of juve- 
niles, non-breeding adults, or both. The same pattern was also 
observed in Kazakhstan. 
The mating system of the Houbara Bustard is still unknown. Some 
authors Cramp & Simmons (1983) have suggested that the species is 
probably monogamous, but others consider the Houbara mating sys- 
tem to be polygynous or promiscuous (Collins 1984, Ponomareva 
1983, Launay & Paillat 1990). It is possible that the mating system 
could be partly density-dependent, as suggested by our observations 
in Kazakhstan and Turkmenistan. In areas of low density breeding 
occurs in different places each year with each male displaying alone 
(Atumaradov pers. comm.). At high densities, groups of males (the 
same number from year to year) display on traditional display 
15 
