Common gull / Sturmmöwe (Larus canus)

Near Badi Auslikon at the Pfäffikersee. I thought I had only seen black-headed gulls, but on reviewing my photos, I noticed the yellow bill. Other typical characteristics: it's bigger than the black-headed gull next to it, it doesn't have the Charlie Brown half-ring around the eye, it has less gray and only a few shorter black tail feathers. 2021-02-05 11.34.30 Pfäffikersee
Classification: Genus Larus; Subfamily Larinae; Family Gulls (Laridae)
This bird appears across the great seas in the following continents: Europe, North America, Africa.
Not so common in Switzerland (most common would be the black-headed gull as far as I can see
Appearance and identification: Nabu: NABU ueber das Aussehen der Sturmmoewe: 'Sturmmöwen sind etwas größer als Lachmöwen, jedoch deutlich kleiner als Silbermöwen. Sie sind überwiegend weiß mit grauem Rücken und grauen Flügeln. Die Flügelenden sind schwarz mit weißer Spitze. Der Kopf ist rundlich, die dunklen Augen dünn rot umrandet. Der schlanke Schnabel und die Beine sind grünlichgelb, ein Schnabelfleck fehlt.' [Portraet]
Vocalization: Various mewing sounds. Similar in form to Herring Gull, but much higher pitched. [Link]
Physical details: length=40-42 cm, wingspan=100-115 cm, weight=300-480 g
not sexually dimporphic.
Identifying characteristics: general: head = white (Gray in winter and when young), beak = yellow (greenish yellow), legs = yellow (duller in winter), , , , Adult: wings = gray, , , Youth: wings = white (with brown streaks), , Winter: tail = black (and white striped), Prachtkleid: tail = white
Habitats: River and lake

First documented observation : 2021-03-07 in Rapperswil.