The Petrel Station Seabird Trip Report (1st Nov 2020), Tutukaka, NZ : South Polar Skua, Mottled Petrel & Wilson's SP

[ourspot]

Had another great day out at The Petrel Station yesterday (1st November) on the latest pelagic seabird trip offshore from Tutukaka (in Northland, New Zealand). Conditions were a smallish swell and steady 10-15 knot winds through most of the trip which dropped right out later in the afternoon.

The highlights of the trip were:
– 1 South Polar Skua which delivered stunning flybys around the boat for about 10 minutes
– 1 Mottled Petrel that briefly visited
– 1 Wilson's Storm Petrel and 30+ New Zealand Storm Petrels

During the trip we saw 22 different seabird species, and over 11,000 seabirds in total. A nice finale to the trifecta of Tutukaka spring migration pelagic seabird trips that have gone out in the last 3 weekends :) See the full trip list below.

If you’re interested in coming out on a pelagic seabird trip to The Petrel Station then check out the upcoming trip dates on our website and get in touch – it’s always a great day out. Find out more at: www.thepetrelstation.nz

Cheers
Scott Brooks
The Petrel Station pelagic seabird tour
Tutukaka, New Zealand

P : 021 322 324
E : seabirds@thepetrelstation.nz
Facebook : www.facebook.com/thepetrelstation
YouTube: www.youtube.com/@thepetrelstation
Instagram : www.instagram.com/thepetrelstation

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Here’s the full trip results:
1 x SOUTH POLAR SKUA
1 x MOTTLED PETREL
60 x Cook's Petrel
2,500+ x Fairy Prion
5 x Grey-faced Petrel
30 x Black Petrel
65 x Flesh-footed Shearwater
5,000+ x Buller's Shearwater
12 x Sooty Shearwater
2 x Short-tailed Shearwater
80 x Fluttering Shearwater
40 x Little Shearwater
1 x Wilson's Storm-Petrel
32 x New Zealand Storm-Petrel
12 x White-faced Storm-Petrel
1,400+ x Common Diving-Petrel
800 x Australasian Gannet
14 x White-fronted Tern
1,200 x Red-billed Gull
12 x Black Backed Gull
53 x Pied Shag
1 x Little Pied Shag

[rowey]

Does sound a great day indeed. Would have been 11 lifers for me on that list.

What are your plans going forward? I could possibly make a long weekend out of Christchurch for a trip in the new year. Any potential dates at this stage??

Regards

Kieran

[Tim Barnard]

welcome your thoughts ...

[sav]

Hi all,

Thanks for the photos Tim. I haven't seen very many South Polar Skuas, and don't claim to be an expert on large skuas. I also acknowledge that seeing the bird in the flesh gives one a different perspective - but I'm interested to know why this isn't an immature Brown Skua?
The bill on this bird is really big - and I would have thought too big for SPSK?? It also looks like a big, chunky, bird - not that SPSK is dainty, but it has a different "lighter" jizz to my mind.

Any other thoughts - particularly from those present?

cheers

[tony crocker]

Hi Sav et al

The smooth 'even' plumage is correct for South Polar, as is the collar, but you are right- SP is a much lighter, finer bird than brown types and the photos don't indicate size. They also hybridise!

[Steve Wood]

I agree with Tony’s comments -
The pale /yellowish nape patch I believe to be consistent with S P Skua and is highlighted well (second image ) and is, I believe an intermediate morph bird.
For a Sub Ant Skua I would have expected more individually flecked pale/yellow appearance on nape and generally darker headed
The fairly consistent paler head,neck and underparts also fits better with SP Skua.
Juv Sub Ants Skua that I have seen were generally all dark lacking any contrast in plumage and all were all dark headed lacking any paleness or nape colouring.

Bill size and overall size hard to comment.

[ourspot]

Hi all

I've been having very interesting and educational discussions about the South Polar Skua we saw on the day wth a Skua expert called Vincent Mourik (he's based in Australia). Here's a summary of what he says about the bird:

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"So as to the South Polar Skua seen on 1st Nov:

Its simply too light for a Brown Skua. some pictures show it lighter, some darker, but overall it has grey brown colour, and its sort of a mid-brown, not dark brown. Again, its cold grey brown, not warm.

Brown's only get that light when they're very worn. But this is a fresh looking bird, it just moulted. There's no extreme wear. The scapulars and flight feathers look very fresh to me. The marking on the scapulars are rather typical for South Polar, but atypical for Brown. I think it's an intermediate morph, towards the darker end, I'm not sure if intermediate morphs get even darker than this, i.e. a truly gradual transition into dark morphs. Perhaps the intermediate morph can be slightly darker than this, I might have seen cases like that. And when I say that Brown's can get this light when worn, mind you it's a different tone you get. It's more yellowish. And never as homogeneous, there's always darker and lighter feathers.

Going by moult timing it's an older imm or adult bird.

The heavy bill: yes the bird has a heavy bill. South Polars can have stout bills, appearing very similar to Browns. I wouldn't not use this as a strong discriminating character. Bill shape - unreliable character in my opinion.

Overall Structure looks fine for South Polar to me, pretty short tarsi which is good for south polar as well."

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And here's a few more images of the bird as well

Cheers Scott
Tutukaka Pelagic Seabird Trips Organiser

[Steve Wood]

Even more obviously SP with these better quality
Images.

[Tim Barnard]

Great conversation ... one more feature is the amount of white in the flash on the upper wing. A broader flash is more consistent with the range of variation in SPS.

[sav]

Hi all,

It is a great conversation, and I guess you learn something every day !

I was very interested to hear the news that bill shape and size are unimportant.

Every reference that I have to hand indicates that bill size IS important. According to HANZAB, there is no overlap in bill length between the 2 species, and even then the smallest-billed Brown Skuas are from the Atlantic...

Like I said before, the guys who were actually there have a better handle on this than I have, particularly when it comes to plumage shades, and to the bulk/shape/jizz of the bird in the flesh.

cheers