Archer has been travelling over the Sahara for the past couple of days, but as stated in the overview post, it isn’t all featureless sand. These two images of her route show the variety in the landscape below her.
It is worth repeating Paul’s reply to Sally’s query (‘Comments’ under last post) about the formation of the hills in the Es-Semara region of the Sahara.
“These outcrops are known locally as “guelbs” (which is simply the Arabic word for a small hill). They are the result of differential erosion relative to the surrounding rock. Today, the primary erosion agent is wind-blown sand but, in past eras when the western Sahara was much wetter than is is now, rainwater carved these features and left them above the general elevation. Further south, along the margin of the pre-cambrian shield, many of these geulbs are rich in iron ore and other minerals and open-cast mining of them is a major industry.”
As she did on 10 September, Archer roosted on the floor of old river valleys. There is water in them occasionally – she has used small trees or bushes for her roosts.
On both 11 and 12 September, Archer moved position in the early hours. Her later roost is on the left in the above image.
Trivia ‘coincidence of the day’ – last night, Archer’s roost was under 50 km from Rutland Osprey Project‘s 30(05)‘s river bed of choice on 3 September. Archer’s recent track has been quite close to that experienced female’s usual route for her desert crossings.
Whichever route Archer takes today – continuing south through the desert, or heading towards the coast – she could be in Senegal by the weekend.