Species reshuffling and climate change

[MichaelF]

Bitterns were thought to have been partly hunted out (along with drainage)

Drainage is by far the more significant factor here!

herons will be a doddle! (can't see how they're less conspicuous than egrets - same colonial nesting, same racket and smell, and they're bigger to boot)

Much wider breeding range, including areas with very low human population density (e.g. western Scotland) where they could thrive with minimal disturbance, and recolonise rapidly whenever hunting pressure dropped in England.

they [Collared Doves] are in Portugal and mostly in my garden, but where did they come from originally?

India, before the great expansion westward started. If you want to get away from them, try up here - they're decidedly scarce here. But you'll have to put up with Wood Pigeons instead

[mafting]

Originally Posted by MichaelF

Drainage is by far the more significant factor here!

Agreed, although hunting was apparently widespread. Worth remembering that many marshes were 'worked' until recently - fowlers, eel-catchers, etc.

Originally Posted by MichaelF

Much wider breeding range, including areas with very low human population density (e.g. western Scotland) where they could thrive with minimal disturbance, and recolonise rapidly whenever hunting pressure dropped in England.

But population was much higher in W Scotland back then....if they managed to wipe out wolves, beavers and most of the native forest, then heronries would have been obvious and easy I'd have thought.

Originally Posted by MichaelF

India, before the great expansion westward started. If you want to get away from them, try up here - they're decidedly scarce here. But you'll have to put up with Wood Pigeons instead

Indeed, don't quite get Colin's point here - they could have walked to his gaff if they wanted to! They originated in Asia, spread into the Balkans by around the 20s, and then colonised the rest of Europe at a rapid rate. In the US, they escaped/released in Bahamas in the 70s, then spread to Florida by the 80s, and then marched westwards and are now at the Pacific. Unless his birds are African Collared Doves?