Ostrom's Menace-from-the-Clouds Bird

Rahonavis ostromi

    The island of Madagascar was once part of the continent Gondwana, but has now drifted off into isolation along with India.  Because it has been isolated for so long, it supports many primitive Jurassic animals into the Late Cretaceous.  Probably the most interesting is the crow-sized bird, Rahonavis ostromi.
    The primitive bird Archaeopteryx had a raised claw on each inner toe, these claws functioned as  pitons for use in climbing trees.  In R. ostromi , these raised toes have curved into sharp talons.  The talons' function is similar to the raised toes of Archaeopteryx, they are pitons, but are now used to climb up live animals.  R. ostromi is a parasite-eater, it cleans the hides of larger animals of ticks wich it eats itself.  It uses its enlarged inner talons to clamber up the backs of large animals and to dig out dermal parasites from crevasses.
    Although its role as a tick-eater is symbiotic, R. ostromi is also, at times, a parasite itself, for it does not eat the ticks for their flesh, but for the blood inside them.  Therefor, whenever the large host-animal has an open wound, R. ostromi will ignore the ticks and feed directly from the wound.
    At some point in the past, a breakthrough was made when birds like this discovered that their talons could inflict wounds themselves.  It was at this point that they ceased being symbiotes and became predators.  Descending onto the ground, these animals lost their powers of flight as their legs strengthened.  Their raised inner toes grew larger reletive to their bodies and their eyes shifted forward into stereoscopic vision.  By the  Cretaceous, period while their primitive relatives still live in Madagascar, these flightless birds, the deinonychosaurs, have become the dominant small predators of Asia and North America.

•  Jeff Poling's articles
• Dinosaurs and Evolution 3
• Feathered non-avian theropods discussion
• Sickle-clawed bird discovered
• T. Mike Keesey's Rahonavis page
• Megalania's articles
• A description of "Rahona" (Rahonavis) , a primitive bird ancestral to theropods.
• A discussion of Rahona , Shuvuui and the dinosaur-bird connection.
• The ABCNEWS article, A Bird With a Dinosaur Toe?
• The Theropod Ancestry of Birds: New Evidence from the Late Cretaceous of Madagascar   by Catherine A. Forster, * Scott D. Sampson, Luis M. Chiappe, David W. Krause
• Luis Rey's Chirostenotes painting (includes Rahonavis in the backround)
• Øyvind M. Padron's Rahonavis