daily counts were made. There are several possible explanations for this: 
• the migration was later in 1991 
• any narrow-front migration route for this species does not 
follow the escarpment 
• the species has a more dispersed migration throughout the area. 
There is circumstantial evidence for the first of these explanations. The 
general impression of researchers based in both Taif and Riyadh, and of 
Bedouin falcon-trappers at Al Lith, was that the migration of raptors in 
1991 was both smaller and later than in previous years. There are, 
however, no documentary data available to support this and any variation 
could simply be a natural fluctuation. 
The Steppe Eagles which migrate through Arabia originate from breeding 
grounds covering an area extending from the Black Sea to the Kirgiz 
steppes. The route these birds use to reach the peninsula is unknown, but 
there are various possibilities (Welch and Welch, 1991) including broad- 
front migration from the Caucasus, and concentrated migration round 
the Arabian Gulf - at the northern end through Kuwait, and at the 
southern end via the Strait of Hormuz. There is evidence that each of 
these routes is used by some birds, but the relative proportions at each 
has yet to be determined. Thus the birds enter Arabia from several widely 
separated points, and with few geographical features to channel them it 
is possible that they continue on a broad front until they are funnelled at 
the southern tip of the peninsula across the Bab-el-Mandeb straits. If this 
is the case, one would expect the Steppe Eagles to pass on a generally 
broad front through Saudi Arabia, gradually becoming more concentrated 
as they move south and west. This could also account for the frequent 
scattered sightings of small numbers of eagles throughout much of 
northern Arabia. In contrast to the relatively srnall number of eagles 
counted at Al Hada during this study, casual observations made in the 
Abu Arish area in October 1987 noted over 800 Steppe Eagles in four 
hours (P Symens in litt), which tends to support the idea that the 
movement becomes more concentrated as it moves southwards. 
Of the other raptor species recorded. Honey Buzzard Pernis apivorus, 
Black Kite Milvus migrans, Egyptian Vulture Neophron percnopterus and 
Booted Eagle Hieraaetus pennatus all tend to be early migrants and thus 
no significant numbers were expected. Conversely, Long-legged Buzzard 
Bu teo rufinus and Imperial Eagle Aquila heliaca are late migrants with their 
main migratory period being in late October and November. The very 
small numbers of these two species at the end of the count are thus likely 
to be the start of the movement. Among the remaining species, 
Sparrowhawk Accipiter nisus, harriers Circus and falcons Falco are more 
'active' migrants, and thus are not concentrated at narrow sea crossings 
as are the broad-winged species. 
7 
