I doubt there is a clear difference between the "Pyramid Prions" on these two islands. Fulmar Prions are only prion species with striking sexual dimorphism in bill size, the heavy swollen ones should be males.
I'd be pretty happy to see one identifiable bird too but off the breeding colony there should have been a number so my guess is the one you have identified is an extreme phenotype - a large male most likely. I'd also guess that there were others there that you saw and weren't able to identify.
It's all (and always?) early days in the identification of prions as we keep moving further along. The DNA work is helping a lot and the field work will lag behind that because it is harder to get to these birds. I started trying to identify prions when I read Peter Harper's 1980 paper on them (https://www.birdsnz.org.nz/wp-content/u ... s_27_3.pdf). It seems pretty basic now but it wasn't when it was written and you may still find bits that help.
Ian
Chatham Island Prions
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Ian Southey
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Steve Wood
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Re: Chatham Island Prions
I agree, based on the close proximity of the islands the Pyramid P. are likely to be the same is my guess also.
if you don’t mind forwarding the info that states male Pyramid Prions bill sizes are different that would be much appreciated.
According to NZ birds online regarding Fulmar Prions - “However at other colonies (Chatham and Auckland Islands), fulmar prions are mainly active ashore nocturnally.” This would explain why only one bird was captured on film so to speak, as their feeding grounds are off shore and don’t hang around during the day.
I know science is never finished and the more we know, the more we don’t know, but there is something for Me here that doesn’t quite stack up and I still have questions that I feel haven’t been satisfactory answered. Thanks for your Comments Ian.
Are you there Alan T “)
if you don’t mind forwarding the info that states male Pyramid Prions bill sizes are different that would be much appreciated.
According to NZ birds online regarding Fulmar Prions - “However at other colonies (Chatham and Auckland Islands), fulmar prions are mainly active ashore nocturnally.” This would explain why only one bird was captured on film so to speak, as their feeding grounds are off shore and don’t hang around during the day.
I know science is never finished and the more we know, the more we don’t know, but there is something for Me here that doesn’t quite stack up and I still have questions that I feel haven’t been satisfactory answered. Thanks for your Comments Ian.
Are you there Alan T “)
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David Riddell
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Re: Chatham Island Prions
The material on sexual dimorphism in fulmar prion bills is in the Peter Harper paper that Ian linked to (p. 276 and following, particularly Fig. 15). I've been following this discussion closely because I'm hoping to get out to the Pyramid at the end of the month (weather permitting) and I have to admit I'm finding it all fairly bewildering - so much variation with different subspecies, moult, life stages and now sexes. I'm hoping I'll be able to pick up at least one big chunky (presumed) male like in Steve's original picture, but obviously separating these species at sea is a huge challenge. One thing that intrigues me, I've seen several references to fulmar prions have a distinctive "looping" flight. I'm a bit vague about what this precisely means, and I wasn't even sure if it applied to Pyramid prions, given that they now appear to be separate from fulmar prions sensu stricto. But I see that Harper reports seeing this flight pattern off the Chathams in 1967 so (assuming it wasn't an off-course bird from the Bounties) perhaps the Pyramid birds also do this. Was this observed on your trip Steve?
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Steve Wood
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Re: Chatham Island Prions
Hi David, Thanks for that info. i will check it out when I get a moment.
No looping flight patten observed. The Prions seen and photographed were briefly around the boat,passing through and periodically investigating
the substantial slick which we created. The Pyramid Prion,by all accounts, doesn’t seem to behave like the Fulmar Prions on the Bounty’s and are not plastered over the rock faces. Hopefully you have a good camera at hand as you are probably going to need it to see what you are looking at!
Good luck, an awesome place to go birding:).
No looping flight patten observed. The Prions seen and photographed were briefly around the boat,passing through and periodically investigating
the substantial slick which we created. The Pyramid Prion,by all accounts, doesn’t seem to behave like the Fulmar Prions on the Bounty’s and are not plastered over the rock faces. Hopefully you have a good camera at hand as you are probably going to need it to see what you are looking at!
Good luck, an awesome place to go birding:).
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David Riddell
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Re: Chatham Island Prions
Have to admit my camera is far from the best in the world (e.g. compare my shots of a thin-billed prion off Kawhia - viewtopic.php?f=9&t=7888&p=37571#p37574 - with Oscar's of the same bird! - viewtopic.php?f=9&t=7888&p=37571#p37578 - the quality of the photographer may also have something to do with it...), and I'm not sure how much chumming will be done on this trip. I suspect we'll have to be lucky to get a definite Pyramid prion, but there should be plenty of other things to see. I'll definitely be closely inspecting every prion that goes past!
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Dave Boyle
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Re: Chatham Island Prions
The prions in the Chathams are an absolute nightmare.
The Fulmar Prions on The Pyramid look pretty distinctive, they're pretty plain & have obvious big chunky bills, I've not noticed any obvious sexual dimorphism in bill size, they've all got chunky bills. They only come in at night, or dusk at least - last time I camped on the island we were estimating we were seeing a good 2-3000 birds coming in. I've never seen the distinctive looping flight. From photos, I think you'd be hard pressed to find any obvious differences with the Fulmar Prions from the Bounties, & there's no reason why these birds couldn't be foraging in Chathams waters.
The Fulmar Prions on the 44s look different, as surprising as that might seem. When the paper came out proposing Fulmar Prions on The Pyramid be split I was asked for some photos & went through my photos from The Pyramid then from the 44s & I couldn't believe they were the same species, I was even thinking the 44s birds weren't Fulmar Prions. For years Hadoram Shirihai has been aware of a distinct Fulmar Prion in Chathams waters but it wasn't until he saw photos from the 44s that he realised where these birds were coming from. These birds have smaller bills, there's nothing that approaches the bills of The Pyramid birds, & some have bills so much smaller there's no way you would ever think they were Fulmar Prions in the field - I guess this could be down to sexual dimporphism? They also have more obvious dark caps & dark masks - they're definitely far more obviously different to Pyramid birds than Pyramid birds are to Bounties birds.
Then, carrying north, you come to the Sister's, which has very similar habitat to the 44s but there its only Fairy Prions - albeit Fairy Prions with bigger bills than lots of photos you see of Fairy Prions from New Zealand & also plainer faces & greyer flanks.
The recent paper only had skins from the 44s prions to work with, not blood samples, so I'm not sure we've got the full picture in the Chathams yet - I wonder if the 44s could be a hybrid species, similar to Salvin's Prion, but maybe the recent work can rule that out, I don't know. I also don't really understand why one island only has Fairies & other islands only have Fulmar Prions but that seems to be the case in The Snares too
The Fulmar Prions on The Pyramid look pretty distinctive, they're pretty plain & have obvious big chunky bills, I've not noticed any obvious sexual dimorphism in bill size, they've all got chunky bills. They only come in at night, or dusk at least - last time I camped on the island we were estimating we were seeing a good 2-3000 birds coming in. I've never seen the distinctive looping flight. From photos, I think you'd be hard pressed to find any obvious differences with the Fulmar Prions from the Bounties, & there's no reason why these birds couldn't be foraging in Chathams waters.
The Fulmar Prions on the 44s look different, as surprising as that might seem. When the paper came out proposing Fulmar Prions on The Pyramid be split I was asked for some photos & went through my photos from The Pyramid then from the 44s & I couldn't believe they were the same species, I was even thinking the 44s birds weren't Fulmar Prions. For years Hadoram Shirihai has been aware of a distinct Fulmar Prion in Chathams waters but it wasn't until he saw photos from the 44s that he realised where these birds were coming from. These birds have smaller bills, there's nothing that approaches the bills of The Pyramid birds, & some have bills so much smaller there's no way you would ever think they were Fulmar Prions in the field - I guess this could be down to sexual dimporphism? They also have more obvious dark caps & dark masks - they're definitely far more obviously different to Pyramid birds than Pyramid birds are to Bounties birds.
Then, carrying north, you come to the Sister's, which has very similar habitat to the 44s but there its only Fairy Prions - albeit Fairy Prions with bigger bills than lots of photos you see of Fairy Prions from New Zealand & also plainer faces & greyer flanks.
The recent paper only had skins from the 44s prions to work with, not blood samples, so I'm not sure we've got the full picture in the Chathams yet - I wonder if the 44s could be a hybrid species, similar to Salvin's Prion, but maybe the recent work can rule that out, I don't know. I also don't really understand why one island only has Fairies & other islands only have Fulmar Prions but that seems to be the case in The Snares too
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Steve Wood
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Re: Chatham Island Prions
That’s gold Dave !!!!!. Definitely going to try and get to the Sisters to see these “large billed Fairy P.” that you have described.
Thanks for taking the time to explain this complexity as you see it.
Thanks for taking the time to explain this complexity as you see it.
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Ian Southey
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Re: Chatham Island Prions
Dave
I can't dismiss the observations of someone familiar with the birds on the breeding colonies so I remain curious. As David Riddell noted, the idea of sexual dimorphism stems from Harper 1980 and the people that read it but there was not much material available then, whether it would stand up with larger samples is untested. From the pictures of Fulmar Prions from the Chathams that I have been able to see in a quick look I do not, however, think it is clear that these two populations are so different. There's not much to look at and the angles and shadows make it hard to get a good comparison of bill size and shape so it is not ideal material to work with. Certainly, from side on the two populations don't seem so different. I'll be happy to see more if they become available.
I am used to seeing considerable variation in face patterns and bill size and shape in Fairy Prions, Antarctic Prions and Thin-billed Prions and I think the Chatham Island Fulmar Prions are definitely not more variable than them. So saying, I suspect there will be more than one kind of Fairy Prion in the end so that may not mean much. To be sure about this I'd like to know the extent of variation in each population and how much overlap in characters there is. Perhaps, if you have the good fortune to go back to the islands, you could slip some calipers in your back pocket as, even in few spare hours you should easily be able to handle more birds than there are in museums. It would be good to shift from impressions to numbers.
Looking at the recent genetic paper, the gene (COI) that most clearly resolves these two genetic groups - Fairy and Fulmar Prions from the Chathams - actually has very few differences between the two, just one or two base pairs. Without the morphology and behaviour I doubt it would stand up as a species difference but there is simply not enough variability to resolve different groups from within the Chathams. The cytochrome b is either all over the place or needs to be labelled properly. Perhaps other genes will be found that can do this better but it may be that old fashioned natural history will work best - morphology, ecology, behaviour and calls.
Ian
I can't dismiss the observations of someone familiar with the birds on the breeding colonies so I remain curious. As David Riddell noted, the idea of sexual dimorphism stems from Harper 1980 and the people that read it but there was not much material available then, whether it would stand up with larger samples is untested. From the pictures of Fulmar Prions from the Chathams that I have been able to see in a quick look I do not, however, think it is clear that these two populations are so different. There's not much to look at and the angles and shadows make it hard to get a good comparison of bill size and shape so it is not ideal material to work with. Certainly, from side on the two populations don't seem so different. I'll be happy to see more if they become available.
I am used to seeing considerable variation in face patterns and bill size and shape in Fairy Prions, Antarctic Prions and Thin-billed Prions and I think the Chatham Island Fulmar Prions are definitely not more variable than them. So saying, I suspect there will be more than one kind of Fairy Prion in the end so that may not mean much. To be sure about this I'd like to know the extent of variation in each population and how much overlap in characters there is. Perhaps, if you have the good fortune to go back to the islands, you could slip some calipers in your back pocket as, even in few spare hours you should easily be able to handle more birds than there are in museums. It would be good to shift from impressions to numbers.
Looking at the recent genetic paper, the gene (COI) that most clearly resolves these two genetic groups - Fairy and Fulmar Prions from the Chathams - actually has very few differences between the two, just one or two base pairs. Without the morphology and behaviour I doubt it would stand up as a species difference but there is simply not enough variability to resolve different groups from within the Chathams. The cytochrome b is either all over the place or needs to be labelled properly. Perhaps other genes will be found that can do this better but it may be that old fashioned natural history will work best - morphology, ecology, behaviour and calls.
Ian
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Michael Szabo
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Re: Chatham Island Prions
Hi Ian,
When you say "I am used to seeing considerable variation in face patterns and bill size and shape in Fairy Prions, Antarctic Prions and Thin-billed Prions and I think the Chatham Island Fulmar Prions are definitely not more variable than them" - do you make that comment based on seeing beach wrecked birds up in Auckland or live birds at sea off the Chatham Islands?
Cheers,
Michael
When you say "I am used to seeing considerable variation in face patterns and bill size and shape in Fairy Prions, Antarctic Prions and Thin-billed Prions and I think the Chatham Island Fulmar Prions are definitely not more variable than them" - do you make that comment based on seeing beach wrecked birds up in Auckland or live birds at sea off the Chatham Islands?
Cheers,
Michael
'New Zealand Birders' Facebook group: https://www.facebook.com/groups/857726274293085
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Ian Southey
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Re: Chatham Island Prions
Michael
I have never identified a Fulmar Prion from the Chathams, even provisionally. I just looked up photos on the net.
I have, however, looked at prions at sea since the 1980s when people were only identifying Fairy-type from others based on tail bands. Digital photography and modern gear have helped a lot. For beach patrolled birds faces are often wet and dishevelled, some degree of decayed or just full of sand so not often there is not much to be seen. I rely on bills which are tried and true and, as part of a wider wreck in the 1980s, once found three birds identifiable as pyramidalis from the measurements in Harper 1980 but plumage details were not visible. With good pictures bills can also be useful for birds at sea.
Sometimes birds from particular places seem distinctive but when I go back I often find them less clear than I remembered so I don't have any useful answers. There is considerable variation in crowns, supercilia, and eye stripes and also the amount of blue on the body. Birds from breeding islands would be better to work with because then you'd know they were local and not just flying by.
Ian
I have never identified a Fulmar Prion from the Chathams, even provisionally. I just looked up photos on the net.
I have, however, looked at prions at sea since the 1980s when people were only identifying Fairy-type from others based on tail bands. Digital photography and modern gear have helped a lot. For beach patrolled birds faces are often wet and dishevelled, some degree of decayed or just full of sand so not often there is not much to be seen. I rely on bills which are tried and true and, as part of a wider wreck in the 1980s, once found three birds identifiable as pyramidalis from the measurements in Harper 1980 but plumage details were not visible. With good pictures bills can also be useful for birds at sea.
Sometimes birds from particular places seem distinctive but when I go back I often find them less clear than I remembered so I don't have any useful answers. There is considerable variation in crowns, supercilia, and eye stripes and also the amount of blue on the body. Birds from breeding islands would be better to work with because then you'd know they were local and not just flying by.
Ian