In http://cas.bellarmine.edu/tietjen/images/theropod_ancestry_of_birds.htm#B1 , Catherine A. Forster et al. tell us:
"The digits of the left foot of Rahona were found in articulation and show that digit I is reversed relative to the other digits, a configuration known only in birds."
Does it mean that _Rahonavis_ was capable of perching like extant birds, and much easily than _Archaeopteryx_?
Friendly - Luc J. "Aspidel" BAILLY.