It is estimated that about 30,000 Ring-billed Gulls nest at Tommy Thompson Park in Toronto. I saw that number and likely many more gulls in about 30 minutes in the harbour at Lima, Peru.
These are Franklin’s Gulls.
Franklin’s Gulls nest in freshwater prairie and open-country marshes with patches of emergent and floating vegetation in the western United States and Canada. They migrate mostly through the continent’s center, utilizing agricultural fields, marshes, reservoirs, and many other habitats. Franklin’s Gulls winter mostly along Pacific coastline of Peru and Chile.
After the breeding season, they gather by the tens of thousands on South American coasts as these photographs indicate.
Franklin’s Gulls were not the only birds nearby.