An example of evidence supported by the theory of evolution is the traits of some animals and the type of food they eat. For example, birds with triangular-shaped bill usually eat seeds; birds with long bill eat fish, also birds with slim and long bill eat nectar.
Evolutionists believe that these differences between them were a natural adaptation to survival, which is inconsistent, taking account that birds have the capacity to immigrate, looking for food in different environments. Also, to determine if the bill of the different species of birds has been adapted to the environment or if they always have the same characteristic since the beginning and were created to balance the ecosystem, only