Gentoo
Guest
Just curious what it takes to constitute a subspecies. Some species have some differences regionally but are not considered subspecies. Herring Gulls in North America are an example I can think of. There are differences in wing tip patters and often in size between eastern and western NA populations. However unlike similar differences in Europe where there are two subspecies, the NA birds are not recognized as subspecies. Likewise with the NA and Asian populations of Glaucous-Winged Gull.
So what does it take for two populations to be considered subspecies?
So what does it take for two populations to be considered subspecies?