Snow is uncommon on the breeding grounds, though on several 
occasions in March in north-central Turkey I observed small flocks of 
imperials while light snow from a late storm covered the ground. In 
the same area a few sandgrouse were normally to be found throughout 
the winter in the face of occasional snowfalls that might last from 2 
to 4 days. Dement'ev (15) also mentions Khomyakov (1901) as noting 
flocks of imperials during a snowstorm in late autumn near Ryazan. 
With the advent of the first small snowfall, usually in late October 
or November, most of the birds moved southwards. 
Of the winter range 
The wintering grounds of the imperial sandgrouse lie between the 
January isotherms of 40° and 65 °F. in Asia and 50° and 65°F. in North 
Africa and the Iberian Peninsula. The regions of largest winter con- 
centrations are between the 50° and 60°F. isotherms. Average maximum 
temperatures for January are mainly from 50° to 70°F. with a low of 
39°F, in south central Turkey and a high of 84°F. in Saudi Arabia. 
Average minimum temperatures for January lie mainly between 23° and 50°F. 
with a low average minimum of ~3°F, at Tashkent (Siberia) from which area 
considerable numbers of these birds are reported on warm winters (15). 
Most imperials arrive on their wintering areas in November, when 
average | maximum temperatures are from 50° to 85°F, and average minimums 
from 33° to 55°F. Birds usually leave the wintering grounds in late 
February or early March when average maximum temperatures are from 60° 
to 85 oF. and average minimums from 30° to 55°F. Temperature data for 
49 stations representative of winter range are presented in table 6. 
Precipitation within the winter range of the imperials is normally 
between 10 and 20 inches a year, though as low as 3.2 inches in Saudi 
Arabia and as high as 33 inches in northwestern India. Two patterns of 
winter precipitation are evident. In Spain, North Africa, the Middle 
East, and southwestern Siberia the major part of the precipitation for 
the year comes in winter. This situation is reversed in India and 
West Pakistan. The amount annually received from November through 
February varies from 0.79 inches at Bikaner, India, and 1.1 inches in 
Saudi Arabia to 16.4 inches at Mardin, Turkey. Snow is unknown over 
most of the wintering range, though it occasionally occurs for brief 
periods in southwestern Siberia, in southern Turkey and in Spain. 
Of the "resident" range 
Since few if any imperial sandgrouse have been banded and retaken, 
one cannot state with certainty that they are resident throughout’ the 
year in any part of their range. As previously noted, many authors 
have indicated these birds to be resident in a long narrow belt stretching 
from Spain and North Africa to southwestern Siberia (fig.18). The basis 
for this judgment has been the presence of these birds throughout the year. 
As mentioned elsewhere, this is by no means an infallible indicator of 
residency. Resident is here used to define the areas in which imperials 
are found both winter and summer. 
42 
