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Stewart Island Shag occurrence at Oamaru

Posted: Wed Jan 09, 2019 5:15 am
by Nick Smith
Hi, after over a year since visiting NZ I was going through my 'less good' photos with a view to deleting some when I think I've discovered a bird I didn't know I'd seen. I took some shots of the enormous roost of shag/cormorants on the old wooden pier at Oamaru. It was clear that the birds had loosely sorted themselves out into their different species. At the far end of the pier were what I took to be a mix of adult and juvenile Pied shag, but now when I look, two or three have a clear red throat patch (see photo). The only species I can find like that is the Stewart Island shag. Could someone please confirm this or otherwise - are the bulk of the birds the same? If it is a SI shag, are these usually seen in this area?
Thanks in advance (Full size photo available if required)
Nick (UK)
Shag roost1.jpg
two of the red throated birds
Shag roost1.jpg (281.82 KiB) Viewed 2416 times
Shag roost2.jpg
The 'segregated' roost
Shag roost2.jpg (328.44 KiB) Viewed 2416 times

Re: Stewart Island Shag occurrence at Oamaru

Posted: Wed Jan 09, 2019 8:32 am
by Adam C
Think all the shags in the first shot are Stewart Island shag Paul.

Re: Stewart Island Shag occurrence at Oamaru

Posted: Wed Jan 09, 2019 8:40 am
by Adam C
I cant comment on how common they are down there as I haven't birded the area but pretty sure Pied Shags are reasonably rare on that part of the coast with STIs filling the gap but this is certainly a very large shag party! Is the wharf pretty much an island? Shags obviously love it!

Re: Stewart Island Shag occurrence at Oamaru

Posted: Wed Jan 09, 2019 9:11 am
by David Riddell
The Otago and Foveaux Strait populations of Stewart Island shags are now regarded as separate species - see this discussion - viewtopic.php?t=5370, known as Otago and Foveaux shags respectively.
So those Oamaru birds are Otago shags - reportedly this colony is at least half the total population - viewtopic.php?f=3&t=7155&p=34970#p34947

Re: Stewart Island Shag occurrence at Oamaru

Posted: Wed Jan 09, 2019 4:17 pm
by sav
And they have been there for years.

Re: Stewart Island Shag occurrence at Oamaru

Posted: Thu Jan 10, 2019 7:34 am
by andrewcrossland
Hi Nick, just to summarise all those comments into one quick snap shot - every bird on the end of the pier in your photo is a Stewart Island Shag - the newly split "Otago Shag" taxa. The birds in the foreground are all Spotted Shags. Pied Cormorants are rare in the area and generally night roost in trees, not on jetties in flocks. The Otago Shag has increased substantially in the local area in recent years and the site you photographed is in fact a breeding colony now. Recently also the centre of distribution for Otago Shag has moved northwards into Canterbury with them occurring at the Waitaki rivermouth, Timaru Harbour, Ashburton Rivermouth and occasionally up to Banks Peninsula. There's been one report of a bird near Kaikoura but a UBR is still awaitied (Sav?!)
cheers

Re: Stewart Island Shag occurrence at Oamaru

Posted: Fri Jan 11, 2019 5:35 am
by Nick Smith
Thanks Andrew, Sav, David and Adam, very useful info. I know it sounds lame after all the info but I did think at the time they might be different - but they got lost in all the other species I'd seen for the first time. It was only looking back on the photos recently I spotted the red on one or two birds.
Thanks again everyone, my next question is about Little black shag (or not!) See new thread.