The Life of Birds those birds whose sustenance comes from flesh and their methods of hunting. In New Zealand, Attenborough observes keas, parrots that do not eat meat exclusively, raiding a shearwater's burrow for a chick. However, it is the dedicated birds of prey, such as owls, buzzards, eagles, falcons and vultures, to which much of the programme is devoted. In order to spot and pursue their victims, senses of sight and hearing are very acute. Vultures are the exception, in that they eat what others have left, and once a carcass is found, so many birds descend on it that the carrion seems
Genomic evolution of birds several modifications and deletions which occurred in the exons of the genes implicated in the formation of enamel and dentine. It is thought that the common ancestor of birds already lacked mineralized teeth, and that later genome changes pushed the situation to the current status. Also, birds have the best vision system known in vertebrates. They have a higher number of photoreceptors, and most birds are tetrachromats. The only exception are penguins, which have only three functional opsin genes (and hence are trichromats). This exception could be related to the aquatic lifestyle, since marine mammals have also lost either one