Birdsongs

Nestling growth and song repertoire

size in great reed warblers

The singing behavior of males in song bird species is known to be the basis for mate preference in female birds. Females tend to prefer mating with males that have a larger song repertoire. Female mate preference in animals is mostly associated with benefits, such as good genes, the security of resources and parental care. Therefore, the preference for a male with large song repertoire by the females has to be associated with some form of benefit to the female and her offsprings. According to Nowicki, the song is an indicator of male quality (nutritional-stress hypothesis). He suggested that the brain structure that underlie song learning develops early in life at a time when the young are most likely to experience stress and depending on how much of the stress they experience and their response to it could affect how their brain develops. This in turn affects the extent to which the male birds can learn songs. Thus, the hypothesis suggests that the birds with larger brains are able to learn better and more compared to those with a smaller brain. Therefore, the male birds that better exhibit song preferences dominate over those that do not as they appear phenotypically as well as genotypically superior. I also think that it would be effective and beneficial if the variation in the development of the brain correlated with other aspects such as the ability of the male to provide parental care, resource security, etc.