Hi All (especially people with a good knowledge of gulls)
When Bruce mentioned streaks on the nape the first thing that popped into my
head was that these were retained feathers from a previous plumage (i.e. the
bird has moulted into definitive plumage with its last moult). I have seen
late-stage immature Pacifics with traces of dirty brown on various parts of
the head and breast area, sometimes only a few feathers. However, this is
not absolutely the case, it may be an abberant plumage condition (I recall
an otherwise adult plumage Sooty Tern at Lord Howe with many small blackish
streaks all over the white parts of it's plumage, it didn't appear to be due
to soil/dirt or other material on the feathers but rather part of the
plumage).
I would not jump yet to the conclusion of hybrid, seems premature. Does
anyone know if there are any established records of hybridisation between
these two species?
Bruce: You say the bill was massive - with good views it is usually easy to
separate Pacific from Kelp Gull purely on the relative shape/size of the
bill. Any further comment?
With respect to the white primary tips - does anyone know if freshly moulted
primaries may have white tips in Pacific Gulls which are quickly worn off?
(Although it does seem late for the bird to be moulting - not that I know
much of moult timing and sequence in this species - god I wish I was rich
and had all HANZAB volumes at home!).
The other troubling aspect is the tail being all white. It has been
suggested that old Pacifics can lack the subterminal band, but where has
this suggestion come from? So many remarks from earlier literature (speaking
generally) are based on 'gut feeling' and sometimes they are on the mark,
while others are way off, and some of them are carried through the
generations and become standard knowledge (yet may be flawed!). Has someone
simply speculated that the Pacifics lacking the tail band were old
individuals or was their age known accurately? Could it be that occasional
individuals lack this feature and it is not related to age (as the streaks
on the nape may indicate the bird is not aged)? So many questions!!!!!!
I welcome comments from people more "in the know" with moulting in gulls
(which I am aware is a complex topic having a friend that has worked
specifically on moulting strategies and plumages in some North American
gulls).
Cheers, Dean
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