A summer migrant and not as common as the Common Swift, but we have a lively population of Pallid Swifts here in Portugal, especially along the coast where it breeds both among the cliffs and inside towns. The same size as a Common Swift and the with the obvious sickle wings of all Swifts, the diagnostic features separating it from the Commons are an overall slightly lighter colour, dark brown instead of black, a larger and whiter throat patch and hint of a white forehead, and also a "scaly" appearance to the belly, the latter only really observable with a photo.
Be careful if you're looking skywards at these beauties near the cliff-edge though ...
Joomla Gallery makes it better. Balbooa.com