[4] Its vernacular name is sometimes also used for the dolphin gull, a somewhat similar-looking but unrelated species that is found in coastal southern Chile, Argentina and the Falkland Islands.

A national survey of breeding red-billed gulls carried out in 2014–2016 recorded 27,831 pairs nesting in New Zealand.

The authors of the study based on the survey and published in 2018 said that the accuracy of previous estimates was questionable, but that the species nevertheless appeared to have declined nationally since the mid-1960s.

Since European settlement its numbers have increased, especially around coastal towns and cities where it can scavenge from urban waste.

[citation needed] They nest from October to December in colonies on the coast, either on islands or rocky headlands, cliffs and beaches.