Since her short day of travel on 10 September, Archer has made much better progress.
Archer flew 243 km on 11 September, 215 km on 12 September.
The terrain she has been flying over isn’t flat and featureless desert. It is characterised by many ridges and valleys, as this atmospheric photograph shows.
Many of the hills are 300-400m ASL – just like the fells in and around Kielder Forest.
The winds are light and variable. Archer could fly SW to reach the coast of Mauritania, or head over the desert to the south to reach the Senegal River some way inland, as many ospreys do.