KIST J (1961) Bonaparte s Larus philadelphia, new to the Dutch list. LIMOSA 34 (3): 220-224.

Bonaparte's Gull Chroicocephalus philadelphia = Larus philadelphia On April 19th, 1960, a Bonaparte's Gull, Lams philadelphia. in adult summer plumage was observed near the harbour of Scheveningen. The b'rd was fishing among Black~headed Gulls and could at once be distinguished by its smaller size, wholly white underside of the wings and darker grey mantle which contrasted sharply with the white leading edge of the wings. On April 20th even two birds of this species were seen at the same place. To his surprise the observer, MR. VAN DEN OORD, discovered that the shape of the black on the head did not conform to LODGE'S plate in the Handbook. After~ wards it was established that LoDGE'S drawing is a misleading one, philadelphia having a mask like the Black~headed Gull and not a hood extending well down to the nape as in the Little Gull. Lams philadelphia is new to the Dutch list.

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