Apus pallidus – Apus melba
Summer months at Pikrodafni – urban – stream, one can observe easily 3 Apus (Swifts) species, often in close, spectacular views while the swifts fly just over the water, near the estuary of the stream.
According to the great Couzens book “Identifying birds by behaviour” the Common swifts leave earlier to Africa (Aug) than Pallid Swifts which can stay until Nov. !!