 Manuel too made changes to his second Willow Wren, the "Blue Wren", giving the outer wing washout to improve the stall behaviour.A final development was the Dunstable Kestrel, with the same wing as the "Blue Wren", a fuselage 4 in (102 mm) shorter and 35 lb (16 kg) heavier empty.It built by The Dunstable Sailplane Company which Manuel now had joined.