The difference in plumage coloration of the feral pigeon between Tokyo and Osaka

Abstract

The rock dove Columba livia var. domestica, which is a common feral pigeon species, has a high degree of intraspecific variation in plumage coloration. Although there are many studies on this topic, the last research in Japan was made approximately 40 years ago. In this study, we compared the ratio of color plumage polymorphism of the rock dove between Tokyo and Osaka. We counted the number of pigeons with each plumage variation (“blue bar”, “check”, “black” and “others”; Electronic Appendix 1) at six sites in Tokyo and three sites in Osaka. We found that the proportion of blue bar type, which are known as the wild type, was lower in Tokyo than in Osaka. In addition, we surveyed the photographs of feral pigeons from past newspaper articles. The results showed that the proportion of blue bar type has decreased between the 1930s and 2000s in Tokyo, but the reason is unknown.