Comment on "Narrow primary feather rachises in Confuciusornis and Archaeopteryx suggest poor flight ability".

Nudds and Dyke (Reports, 14 May 2010, p. 887) reported that the primary features of the early birds Archaeopteryx and Confuciusornis were too weak to power flight. This conclusion is not supported because the authors overestimated the mass of the subjects and understated the strength of the primary shafts in at least one example. The total biology of the birds indicates that they could achieve flapping flight.