No Mutants Allowed

probably people letting food out where the birds can get it easily.

Usually seagulls go to the open sea in the winter, and draw to the coasts in summer, but - for reasons that are just giant elephants in the room of society, and a hoax, and not even happening - the seagulls find less food in the ocean, and are becoming significantly more urban

These past 2-3 years I see the first wintering seagulls inside the city, and people have reported seagulls deep into both mountains and forests, first during summers, but now also during winters:
They're moving to wherever they can find steady sustenance.

They are addicted to our wasted food. Their populations have grown because of our garbage.

Seagulls are birds I have never had to deal with due to being nowhere close to the ocean. Got lots of Mourning Doves though.