据5月14日的《科学》杂志报道说，（据一项对鸟类羽毛化石所做的新的研究显示，远古鸟类如Archaeopteryx（始祖鸟）和Confuciusornis（孔子鸟）不是振翅飞翔的动物，它们最多只能算是滑行飞翔的动物。 为了支持这些动力推动的飞行，它们的羽毛必须有足够的强度来支持一个鸟的体重而不会发生翼翅的弯折。 在现代鸟中，这种强度来自鸟羽的中央杆，它能使羽毛沿着其长轴而变得僵硬，而且它是中空的以减轻重量。 生活在约1亿4000万年前晚侏罗纪的Archaeopteryx是否能够振翅飞行一直存在着争议。 有关的争议对Confuciusornis（它们生存于大约１亿年前的早白垩纪）没有给予太多的关注，尽管有很多这种鸟的化石可供研究。 Robert Nudds 和Gareth Dyke对这两种鸟的化石证据进行了研究并发现，Archaeopteryx 和Confuciusornis的羽毛中央杆比现代鸟类的要薄。 他们对在飞行时作用于羽毛的各种力量进行了分析后确定，即使这些中央杆是实心的，它们的强度也只是勉强能够进行滑翔。 因此，动力性飞行可能是在鸟类以后的进化史中才出现的。

参阅文献：Science 14 May 2010:Vol. 328. no. 5980, pp. 887 - 889DOI: 10.1126/science.1188895
 
Reports
Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability

The fossil birds Archaeopteryx and Confuciusornis had feathered wings resembling those of living birds, but their flight capabilities remain uncertain. Analysis of the rachises of their primary feathers shows that the rachises were much thinner and weaker than those of modern birds, and thus the birds were not capable of flight. Only if the primary feather rachises were solid in cross-section (the strongest structural configuration), and not hollow as in living birds, would flight have been possible. Hence, if Archaeopteryx and Confuciusornis were flapping flyers, they must have had a feather structure that was fundamentally different from that of living birds. Alternatively, if they were only gliders, then the flapping wing stroke must have appeared after the divergence of Confuciusornis, likely within the enantiornithine or ornithurine radiations.