Starving Cormorants move in land

[Puffin]

'Overstocked' freshwater lakes and trout farms probably played their part in putting out a wlecome mat as well.

 

 

I think you've probably hit the nail on the head there Leon. Easy availability of food will draw in the species that are able to exploit it. Look at the number of "inland" seagulls for a good example of this. Landfill sites all have their own colonies and we live in an affluent, well-fed society where people can afford to waste food and throw scraps for the gulls thinking they are doing a kindness. An abundance of food leads to a population increase as availability of food is probably the main controlling factor in natural populations. You can cull till you're blue in the face, but while the food supply is being provided by mankind, the birds will continue to migrate in or breed to fill the gaps at the table that are left by the cull.