**BLACK-HEADED GULL

Chroicocephalus ridibundus

Status Vagrant. Scarce Palearctic migrant to New Guinea waters (Beehler & Pratt 2016) with just two records on Biak. 29‒30 March 1963: an immature in Biak harbour (King 1979); February 1991: eight at Biak wharf (Gibbs 1993).