Hi all,
I apologise if this is not the right place to ask this question, or for dumbing the level of this subforum down, but the distribution of Hooded and Carrion Crow intrigues me. When I was younger, and thought of Hooded Crow as primarily a northern form, found across Scandinavia, the distribution on these islands made sense, being found only in northern areas of Scotland and here in Ireland. While the entire island of Ireland lies to the south of the Scottish Hooded Crow distribution, I could easily see a scenario whereby Hooded Crow colonised what are now Britain and Ireland, aided by land bridges, after the last glaciation. Later, Carrion Crow would then have spread north, and displaced Hooded in much of Britain, but Ireland may have been already cut off as an island and thus insufficient numbers of Carrion Crows have ever made it here to displace Hooded.
Perhaps this is what did happen, to a degree, but Hooded Crow, of course, is far from just some 'northern taxon', being found down through Italy, the Balkans, Greece, Turkey and parts of the Middle East. For the scenario I postulated to have happened, birds must have moved north and west from a refugium quicker than Carrion Crow moved north from a more western refugium, and then the events proceeded as outlined earlier. It can't just be that Hooded Crow is inherently better adapted to cooler summers than Carrion is, that doesn't seem to be what is limiting the latter here in Ireland now. Looking at range maps, the presence of Hooded Crow in Ireland and parts of Scotland seems very much anomalous, but I'm sure there are sound reasons for this?
I apologise if this is not the right place to ask this question, or for dumbing the level of this subforum down, but the distribution of Hooded and Carrion Crow intrigues me. When I was younger, and thought of Hooded Crow as primarily a northern form, found across Scandinavia, the distribution on these islands made sense, being found only in northern areas of Scotland and here in Ireland. While the entire island of Ireland lies to the south of the Scottish Hooded Crow distribution, I could easily see a scenario whereby Hooded Crow colonised what are now Britain and Ireland, aided by land bridges, after the last glaciation. Later, Carrion Crow would then have spread north, and displaced Hooded in much of Britain, but Ireland may have been already cut off as an island and thus insufficient numbers of Carrion Crows have ever made it here to displace Hooded.
Perhaps this is what did happen, to a degree, but Hooded Crow, of course, is far from just some 'northern taxon', being found down through Italy, the Balkans, Greece, Turkey and parts of the Middle East. For the scenario I postulated to have happened, birds must have moved north and west from a refugium quicker than Carrion Crow moved north from a more western refugium, and then the events proceeded as outlined earlier. It can't just be that Hooded Crow is inherently better adapted to cooler summers than Carrion is, that doesn't seem to be what is limiting the latter here in Ireland now. Looking at range maps, the presence of Hooded Crow in Ireland and parts of Scotland seems very much anomalous, but I'm sure there are sound reasons for this?
