Iberomesornis had many of the same physical features as modern birds. However, this creature probably did not leave any descendants.
Scientists believe that birds probably evolved from earlier dinosaurs. The feathers, common among birds today, were probably initially used to keep the warm-blooded Dromaeosauridae warm. As birds evolved, they began to use them to aid in flight. Feathers are heavily evolved scales - scales that have in a sense frayed and developed from there to cover the body in intricate filament structures. Iberomesornis lived around 130-120 Million Years Ago, during the fascinating Early Cretaceous Period.
They appeared in Walking with Dinosaurs, Giant of the Skies where they were depicted as having bright blue feathers. They harassed the migrating Ornithocheirus male, though were described as looking 'no bigger than insects', next to the huge adult Ornithocheirus. However, they attacked in numbers relentlessly nipping at the delicate wing membranes of the Pterosaur. At less than 15-20 grams in weight and with a wingspan of less than 20 centimetres, (as big as a large Sparrow) this little avian was certainly tiny compared to the 12 metre wingspan Ornithocheirus. Even so, they drove him off - apparently as they were defending egg laden nests (not that the huge Pterosaur could or would have bothered them) and saw anything around them, even a drinking giant Pterosaur which had no interest in egg nests within dense forests, as potential threats. They would have been pesky little insectivores, with suppliments to their diet of other protein rich foods they could obtain.