Recently I had a lot of tasks of my research so I couldn't go birding. Today's theme is Eastern reef heron. We can observe black and white phenotypes in southern island of Japan ; Okinawa-pref we can see some white-phenotype plumage. And we know that the intermediate phenotype exists. I think it is hybrid of black-type and white-type and maybe has low fitness so the number of intermediate individuals is small. It is said that white-type is advantageous in lagoon. Because lagoon is made by corals so inconspicuous. However it is not easy to image the situation. So today, I will write about "the color ecology".
Black-type foraged in lagoon. Really conspicuous. It could catch a small fish ; pic1. I don't know the view from underwater, but it is undoubtedly that the fitness of black-type in lagoon is not high. I think It is hard time for black-types that forage under the strong sunlight. This photos, I sad down on the beech so this heron didn't notice me. It noticed me until came really near me.
Another example, white-type foraged on the concrete beech. Also, it is surprisingly noticeable. Definitely, the fitness is low. Then why white-type are not distributed in northern parts of Japan mainland? I guess in mainland, the gene pool of small-population phenotype ; white-type is swallowed by large-population phenotype ; black-type. I think it is not the realistic scenario that all white-type individuals dead because of low fitness, only. Gene pool and low fitness affect synergistically. This individual, dived into water a lot time. There are some black patches on it's body, I also whether interested in the condition of individual affects to the plumage color.