Figure 4. Predicted flight styles of fossil birds based on (a) Principal component analysis (PCA) and (b) Discriminant function analysis (DFA).

1,‘continuous flapping’; 2, ‘flapping and soaring’; 3, ‘flapping and gliding’; 4, ‘passerine-type flight’; 5, Archaeopteryx; 6, Confuciusornithidae; 7, enantiornithines and 8, Ornithurines. These results are summarized in Table 2.