A new paper published in Proceedings R Soc B (still as FirstCite) explores the lift generating mechanism in hummingbirds. The study is made by the team Warrick, Tobalske and Powers, i.e. the same group that published a paper on hummingbird wakes in Nature in 2005. This is their follow up, now looking closer to the wing with their PIV cameras. The leading edge vorticity is not as prominent in hummingbirds as found previously for hawkmoths and bats (in Lund), but is more varying and with a mean contribution to lift of 16%. I think that everybody expected a big fat LEV in hummingbirds, being classified as honorary insects by some, and so this study shows an unexpected result. It is always a challenge to explain the unexpected, but we are facing some interesting phenomena here and we should soon be able to compare these results with that of avian hovering, such as in pied flycatchers.
The paper can be found here: