Moult in graellsii & intermedius

(last update: 08 december 2003)

Herring Gull argentatus
Herring Gull argenteus
Herring Gull smithsonianus
Great Black-backed Gull marinus
Lesser B-b Gull graellsii / intermedius
Lesser B-b Gull fuscus
Yellow-legged Gull michahellis
Yellow-legged Gull atlantis
Caspian Gull cachinnans
Armenian Gull armenicus
Baraba Gull barabensis
Heuglini's Gull heuglini
Vega Gull vegae
Mongolian Gull mongolicus
Slaty-backed Gull schistisagus
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Black-headed Gull ridibundus 
Grey-headed Gull cirrocephalus 
Brown-headed Gull brunnicephalus 
 Bonaparte's Gull philadelphia 
Little Gull minutus
Mediterranean Gull melanocephalus
Relict Gull relictus
Audouin's Gull audouinii
Slender-billed Gull genei
Common / Mew Gull canus
Ring-billed Gull delawarensis
Franklin's Gull pipixcan
Laughing Gull atricilla
Kittiwake Rissa tridactyla
Ivory Gull Pagophila eburnea
Ross's Gull Rodosthetia rosea
Sabine's Gull sabini
Great Black-headed Gull ichtyaetus
Sooty Gull hemprichii
White-eyed Gull leucophthalmus
Glaucous Gull hyperboreus
Iceland Gull glaucoides
Thayer's Gull thayeri
Kumlien's Gull kumlieni
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Mystery Gulls
 Skua's Catharacta / Stercorarius
Terns Sterna
Other Birds & Mammals
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 A photograph of a graellsii with suspended P1-P3. This was taken on the 18 June 2001. Peter Stewart has eight birds on his database showing this pattern between the 16 June and 8 July. Seven of the birds are adult and the eighth bird is a third summer. Peter says: "Unfortunately I do not know the time interval between shedding each primary. We do not have enough re-trap material of the same individuals in the same season to work this out. However, it takes some 30 days to replace each of the inner primaries. The first birds with suspended P1 are found in April, so we would expect to catch birds with suspended P1-P3 in June to early July.
My figures show that there is a minimum spread of 94 days for the onset of primary moult. P1 is usually dropped in May (the laying of eggs) for some birds, but not until mid August for others (after breeding). Because of this spread, birds with suspended P1, P1-P2, and P2-P3 will be found at any time between April to early July, and this has proved so from my studies.
I suspect the odd bird will suspend up to P4 as I have birds that have renewed P1-P4 and had recently dropped P5. Many other birds will appear to start moulting normally after suspending P2."

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