Where do the seagulls in Mianyang come from?

The red-billed gull from Siberia is a frequent visitor here every winter and has become an old friend of Mianyang people. Recently, however, a bird that has never been found in Mianyang came to Mianyang for the first time. The name of this rare bird is only one word apart from that of the red-billed gull. It is the "red-billed giant gull".