The herring / lesser black back gull group has a ring distribution around the northern hemisphere. Differences between adjacent forms in the ring are fairly small but by the time the circuit is complete the end members- herring & l.b.b gull are clearly different species.ie in Europe they coexist without interbreeding. For more see the excellent book "The ancestors tale " by Richard Dawkins, or wikipedia, also evolutionfairytale or Talkorigins, Collins photographic bird guide 1990
The herring / lesser black back gull group has a ring distribution around the northern hemisphere. Differences between adjacent forms in the ring are fairly small but by the time the circuit is complete the end members- herring & l.b.b gull are clearly different species.ie in Europe they coexist without interbreeding. For more see the excellent book "The ancestors tale " by Richard Dawkins, or wikipedia, also evolutionfairytale or Talkorigins, Collins photographic bird guide 1990
zytigon 5 months ago