Of Skin and Teeth: Identifying Key Differences in Asians.

the olfactory bulb in birds was also found to correlate with ecological adaptations, including habitat association (e.g., water birds), type of nesting strategy, and diet. For example, birds of prey, including vultures and seabirds, hunt and recognize food by smell, and have relatively large olfactory bulbs, whereas song birds that rely more on cognitive abilities helpful in tool making, vocal learning, and feeding innovations have reduced olfactory bulb sizes. Overall, the role of ecological adaptation in shaping the OR gene families has been found to be consistent in both birds and mammals, indicating the importance of a sense of smell to an animal’s fitness, survival, and niche. Reference