Unknown gull from Mason Bay, Stewart Island

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danh
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Unknown gull from Mason Bay, Stewart Island

Postby danh » Wed Jan 13, 2016 3:14 pm

Hi Everyone,

I've been camping on Stewart Island for a little while so this is a bit late, but on Jan. 8 I was at Mason Bay and saw this gull. I don't know what it is. The pattern of red on the bill along with the lack of a white terminal band on the tail means it doesn't quite fit with a Pacific Gull, my first guess. It's definitely not a black-backed gull. Does anyone have an idea of what it is?

Sorry for the small size of the images, it's due to the forum's upload limitations. I can send anyone who's interested larger (and more) images.

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Screen Shot 2016-01-13 at 3.12.25 PM.png (153.24 KiB) Viewed 2374 times


Dan Hoops
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Neil Fitzgerald
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Re: Unknown gull from Mason Bay, Stewart Island

Postby Neil Fitzgerald » Thu Jan 14, 2016 11:40 am

danh wrote:Sorry for the small size of the images, it's due to the forum's upload limitations. I can send anyone who's interested larger (and more) images.


Hi Dan
You can upload images nearly four times bigger than those. Also, try saving them as jpegs, rather than pngs and you'll usually get better image quality with smaller file size.
SomesBirder
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Re: Unknown gull from Mason Bay, Stewart Island

Postby SomesBirder » Thu Jan 14, 2016 11:57 am

Well, if it's not a black-back, then all I can think of is lesser black-back (Larus fuscus).
what in god's name is a folly tomo
Ian Southey
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Re: Unknown gull from Mason Bay, Stewart Island

Postby Ian Southey » Thu Jan 14, 2016 12:10 pm

Dan

Perhaps not a Pacific Gull, the bill is remarkably deep but not massively expanded toward the tip, the red mark on the bill does not extend onto both mandibles and the tail band is not sub-terminal ie the very tip of the tail is not white.

Not quite sure what to make of it though - a freak Black-back?

Ian
Clinton9
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Re: Unknown gull from Mason Bay, Stewart Island

Postby Clinton9 » Thu Jan 14, 2016 1:04 pm

Two-year-old (2nd summer) Kelp gull, started to moult its primaries on mid December, and just reached its 2nd birthday.
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Michael
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Re: Unknown gull from Mason Bay, Stewart Island

Postby Michael » Thu Jan 14, 2016 1:19 pm

Yep, I've been through websites covering gulls of the world, and have not found a matching exotic gull that may have strayed into our shores. So it's not something rare.
However, several young Dominican/Kelp/Southern Black-Backed Gulls do match the bird, so I'd agree with Clinton.
Latest Lifer: Malaysian Pied-Fantail in Vietnam's Mekong Delta

Happy birding to all who dare to take the challenge
Paul G

Re: Unknown gull from Mason Bay, Stewart Island

Postby Paul G » Thu Jan 14, 2016 2:46 pm

Clinton9 wrote:Two-year-old (2nd summer) Kelp gull

Yep, Clinton9's on the money again. You're a bit of a Laridophile, eh mate?

Since my wife pointed-out the first Pacific Gull, I'm now regrettably locked-on to checking through every damned
bunch of Black-Backed type gulls I see. Most of us (previously including myself) simply disregard these 'Trash Birds'
with one casual glance, then move on to some 'proper birding'.

But don't do it ! The first Pacific Gull for NZ was in January. Tarry awhile and check em out.
Maybe the next one will wait around long enough to be twitchable?
There's some great illustrations of Black-Backs and Pacifics in all plumages and ages in HANZAB, available as a
link from NZ Birds Online. Read up on them. Gulls are an identification field all of their own,
but you can get a practical overview from HANZAB that will arm you well for what will be encountered
in the field.

You've got to be ready. Keep the features up-front in your mind at all times and look hard at them all.
This one's a Black-back with a heavy-ish bill. But there's sure to be a Pacific Gull or two somewhere
in New Zealand right now. Will YOU be the one to find it ?

Good luck
Paul
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RussCannings
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Re: Unknown gull from Mason Bay, Stewart Island

Postby RussCannings » Thu Jan 14, 2016 4:46 pm

Hi all,

I agree that this is a Kelp (Black-backed) Gull with a largish bill (Possibly a male), but as far as age goes--I would call this a "Third-cycle" or in other words--a bird of roughly 3 years of age. Large Larus gulls like this species take roughly 4 years (4 plumage cycles) to reach the typical full-adult look, and this bird is quite advanced in most respects:

1. fully yellow bill, orange gonydeal spot, with little trace of dark markings
2. Crisp white head, underparts and rump, dark slate back feathers
3. jet-black primaries (The white tips appear by the 4th cycle)
4. Yellow-green legs

Indeed it has retained wing coverts and tertials from its second cycle but the rest of the bird indicate a bird in its third year (This is a rough estimation as different individuals molt at different times, and depending on where the bird was born it may have fledged at any month of the year).

Paul is absolutely right in that we should be ever-vigilant for possible vagrant gulls to our shores. Pacific Gull is one of the most likely candidates, with its massive bill, orange tip on both mandibles, and fully black primaries even beyond its third-plumage cycle. Many will know that Franklin's Gull has now occurred multiple times but for anyone interested in studying up more, I would recommend familiarizing yourself with the following species that I consider good vagrant candidates for NZ:

-Slaty-backed Gull
-Black-tailed Gull
-Sabine's Gull
-Common Black-headed Gull
-Laughing Gull

And if you're reeeeeally keen, how about trying to string an Australian Silver Gull out of the Red-bills ;)

Happy gulling,

Russ C
Cambridge, NZ
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RussCannings
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Re: Unknown gull from Mason Bay, Stewart Island

Postby RussCannings » Thu Jan 14, 2016 4:51 pm

Looking at the bird again, the primaries may actually be second-cycle feathers as well--so one might use fancy terms like '3rd-cycle retarded' or '2nd-cycle advanced'--more simply--it's a bird in transition.

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