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Message: <blockquote data-quote="CAU" data-source="post: 1249962" data-attributes="member: 55324">The so-called "butter knife" shape of the wings of Pallid Swift is a rather good pointer, but of course it's not always visible in photos, and Common Swifts may also show it in some photographs.Here are more pictures, look at the shape of the wing in the first one:<a href="http://www.chnf.dk/diverse/gsejler/graasejl_l2.html" target="_blank">http://www.chnf.dk/diverse/gsejler/graasejl_l2.html</a>The second figure after the one labeled as 5 (why didn't the author label them all?) shows the two most scaled samples of 1cy Common Swift found in the Copenhagen Zoological Museum. The caption says that the back and the lesser upperwing coverts are always less scaled than the rest of the bird, whereas Pallids show heavy scaling also on these parts. Moreover, the scales on Common Swifts are thinner and sharper edged. It's also mentioned that that the other of the two samples shows a very large throat patch.</blockquote>