Harriers working in pairs

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Adam C
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Harriers working in pairs

Postby Adam C » Tue Jun 15, 2021 6:08 pm

Something I've never seen before but really neat to watch. Out at Pegasus Wetlands today 2 Harriers were working in tandem. They would group up behind the ponds then approach at different heights. One would come in quite high while the other crop dusted in from another angle. The Shoveler would watch the high bird and then the low bird would suddenly scream in from the left. First try, it very nearly worked with a huge commotion and a brief talon hold on at least one duck. They regrouped about 20 minutes later tried again doing exactly the same thing almost succeeding again. The other possibility is that one bird had learned to use the other as a decoy but I'm positive these 2 were working together watching them circle and start their initial approach together. I'm sure other raptors do this but the first time I've seen Kahu do it. Always been lone undertakers in my book. Very cool to watch!
Last edited by Adam C on Tue Jun 15, 2021 9:24 pm, edited 1 time in total.
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

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Jim Kirker
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Re: Harriers working in Teams

Postby Jim Kirker » Tue Jun 15, 2021 7:00 pm

Hi Adam,

This may be of interest re the harriers. H Guthrie-Smith in "Mutton Birds And Other Birds" writes about a trip to one of the mutton bird islands in Foveaux strait late in October 1911. He compares the hunting habits of skuas on the island and harriers he'd seen previously.

"One of the pleasures of an acquaintance with birds is certainly the complete originality in the habits and character of every species.

The Sea Hawk devours immature Parara, Titi Wainui, and full grown Kuaka, and maybe the supply is felt to be so great that alone there is no more occasion for strife over meat than amongst dogs for strife over water. The ocean tracts, furthermore, may be considered too vast to parcel into lots. There is room for all - enough and to spare. I suspect, moreover, that Skuas sometimes combine to chase, and may have - nay, must have - enough of virtue to share in some degree the common bag, and for these reasons the bird may have learned toleration of his fellows.

Harriers congregated in twos and threes, I have often watched hunting Pukeko during winter months; and the advantages of the game were so obvious that I suppose only the knowledge of each Harrier that all other Harriers are utterly rogues, selfish and untrustworthy, has kept the chance of an hour from developing, as in the case of the more moral Sea Hawk, into custom."

Not sure I can buy his virtuous versus villainous take on the behaviours, but looks like the harriers he saw were up to something similar to yours.

Jim
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Adam C
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Re: Harriers working in pairs

Postby Adam C » Tue Jun 15, 2021 7:21 pm

Yes I remember Guthrie-Smith was particularly unimpressed with harriers. In fact, he hated them in 'Birds of Water, Wood and Waste'. I quite liked his accounts until I read his chapter on the Harrier! Quite odd!

I prefer Edgar Stead's account of the bird (which I should probably read again) Its a pity Edgar Stead only wrote one volume (to my knowledge)

Cheers Jim. I'll do some more digging :)
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

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Adam C
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Re: Harriers working in pairs

Postby Adam C » Tue Jun 15, 2021 7:29 pm

Jim I was lucky enough to purchase this little bundle from 'Arnold Books' in New Regent Street, Christchurch before it sadly closed down years ago. A second-hand natural history book store was my second home as a student. Used to love that place!!
G. Smith.jpg
G. Smith.jpg (554.44 KiB) Viewed 1552 times
Last edited by Adam C on Tue Jun 15, 2021 11:07 pm, edited 1 time in total.
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

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andrewcrossland
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Re: Harriers working in pairs

Postby andrewcrossland » Tue Jun 15, 2021 10:51 pm

Hi Adam,

Edgar Stead wrote 4 accounts of Canterbury birds.

The first was his paper on waders in Trans & Proc:

Stead, E.F. 1923. Notes on the migratory plovers of New Zealand, with records of some additional species. Trans. & Proc. NZ Inst. 54: 490-495.

The second was his chapter in the first Natural History of Canty book:

Stead, E.F. 1927. The native and introduced birds of Canterbury. In: Speight, R., Wall A. and R.M. Laing (eds.). Natural History of Canterbury. Christchurch: Simpson & Williams.

The third was your one: Stead, E.F. 1932. Life Histories of New Zealand Birds. London: Search Publishing

The fourth was a second book on life histories which he wrote and got to at least a mock up, but when the London Publishers showed him the reproductions of his photos for this book he was so disappointed with their poor quality that he decided not to publish. Anyway, that's what his son Roland told me many years ago when I spent an afternoon visiting him in Waipara and asking him a million questions about his dad, who was a bit of a legend and a personal hero of mine....
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Adam C
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Re: Harriers working in pairs

Postby Adam C » Tue Jun 15, 2021 11:00 pm

Great to know Andrew!

Yes that book is golden. I'd love to track down the rest.

Must have been a great experience chatting to his son. Any idea if the unpublished Life Histories is on record anywhere? Although Im sure you would have tracked it down if it was :/
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

Samuel Ullman
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Adam C
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Re: Harriers working in pairs

Postby Adam C » Tue Jun 15, 2021 11:33 pm

Well, just reading E.Steads account on Harriers there is a paragraph where he describes a team of 3 taking down a hare although he interrupted them to find the hare dead but later muses 'But ever since wished that I had waited to see if the three birds, having worked together for the kill, would have harmoniously shared the feast, or fought over it. Almost certainly the latter I think'

I was thinking the same thing :)

I guess what struck me was that one bird was 'acting a role' in a pre-planned strategy as opposed to a group of birds attacking a single target. Again it could have been that one bird had worked out how to fly low and un-detected behind another higher flying bird but I'm sure the attacks were coordinated.
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

Samuel Ullman
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Re: Harriers working in pairs

Postby GrahameNZ » Wed Jun 16, 2021 8:44 am

The Harriers on the Bromley Oxidation Ponds are masters at tag teaming.
Back in the "olde days" when I used to be allowed to go birding there I spent many a winter afternoon watching them.
It would be a whole family group collaborating.
First one bird would make a gentle pass, just starting to round the scaup into a tighter group.
Then a while later the next bird pushing them closer to a pond corner.
This would go on for an hour at times till they were bunched up in the corner.
Then the big male would come screaming in and score a duck.
It wasn't a foolproof method but did have a high success rate.
The birds of course scattered in all directions, so if a fail there was a patient wait till another group started to form and the dance would start again.
The duck was never shared by the group all at once.
The boss bird took it away and had his share then would fly off and the next in the pecking order would move in etc.
You also see the behavior occasionally at Travis, but it's not a regular technique and have only seen 2 birds at a time doing it.
Last edited by GrahameNZ on Wed Jun 16, 2021 5:15 pm, edited 1 time in total.
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Adam C
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Re: Harriers working in pairs

Postby Adam C » Wed Jun 16, 2021 11:28 am

Thanks Graheme. Funny how there's always something new to learn every time you go out and a relatively routine day can turn into something quite satisfying if you sit and watch for a while. Always another chunk of the billion-piece puzzle to put in place.
“Nobody grows old merely by living a number of years. We grow old by deserting our ideals. Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.”

Samuel Ullman
andrewcrossland
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Re: Harriers working in pairs

Postby andrewcrossland » Wed Jun 16, 2021 10:05 pm

At Bromley and along Canterbury shelterbelts and hedgerows I often see Harriers "shadow hunting". They fly low over the line of vegetation with the sun behind them casting their shadow several metres in front and below the bird. By doing this their shadow crosses over a smaller bird feeding or roosting in the top of the vegetation and they jump up in fright. The Harrier pounces and catches them.

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