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AGP en route to New Zealand (1 Viewer)

Just stunning endurance and navigation.
Several days airborne, no food or rest, targeting a spec of land less than a thousand yards wide and less than 10 feet above sea level.
 
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Just stunning endurance and navigation.
Several days airborne, no food or rest, targeting a spec of land less than a thousand yards wide and less than 10 feet above sea level.

Yes indeed, i was thinking about that. It makes me wonder if their evolutionary "strategy" is just to head south into the Pacific, in the knowledge that they will find an atoll within say, 3 - 6 days, where they can refuel for a week or so..? But then again, perhaps not - we know that birds' homing instincts can be amazingly accurate.
 
Yes indeed, i was thinking about that. It makes me wonder if their evolutionary "strategy" is just to head south into the Pacific, in the knowledge that they will find an atoll within say, 3 - 6 days, where they can refuel for a week or so..? But then again, perhaps not - we know that birds' homing instincts can be amazingly accurate.

Just heading out did not work for Amelia Earhart, so it would probably be similarly lacking for plovers.
I do believe these birds have additional navaids that we do not yet understand.
It may be smell, geo-magnetism or something else, but there are other such trans Pacific migrants that perform stunning navigational feats. Some Godwits go from Alaska to Johnson Island, a tiny place southwest of Hawaii, en route to New Zealand. They fly for more than a week non stop and find a speck in the ocean.
 
You guys are thinking from a grounded POV. Last Friday I was bimbling around Southern England with my brother in a Piper Cherokee at a mere 2,500 feet and we could see from Chichester to Exeter from near Salisbury.

Now tell me about the view from 15,000 feet or more and the eyesight of a bird rather than an aging birder.... migrating birds can scan a huge swathe of ocean and have only to vary their course by a degree or so to head for an island a hundred miles out of their way from the distance they can detect it.

Not to mention that even ancient Polynesian sailors recognised that a line of clouds could mean an island generating them: I'm sure birds learn such tricks as well.

I'm not saying its not remarkable. Just that there is less mystery about it than hairless apes with their ground-bound environment think.

John
 
You guys are thinking from a grounded POV. Last Friday I was bimbling around Southern England with my brother in a Piper Cherokee at a mere 2,500 feet and we could see from Chichester to Exeter from near Salisbury.

Now tell me about the view from 15,000 feet or more and the eyesight of a bird rather than an aging birder.... migrating birds can scan a huge swathe of ocean and have only to vary their course by a degree or so to head for an island a hundred miles out of their way from the distance they can detect it.

Not to mention that even ancient Polynesian sailors recognised that a line of clouds could mean an island generating them: I'm sure birds learn such tricks as well.

I'm not saying its not remarkable. Just that there is less mystery about it than hairless apes with their ground-bound environment think.

John

And I think you are looking at this from the POV of somebody for whom the English Channel is a large body of water! ;) Have you seen just how big and empty the Pacific is?!

This is fascinating stuff! Why did the bird change course mid ocean north of Hawaii? Why didn't it stop off in Hawaii despite flying straight over it? Had it previously stopped in Kiribati, and therefore know it as a safe place to stop, or was it a decision made on the wing after spotting land? Do first year birds have a different strategy than experienced adults?
 
Ouch... 3:) I don't think I was, but there's room for debate.

Yes its big, but its not infinite and there is room for using normal sensory information to correct navigation errors.

As for the very sensible questions:

Dunno why it changed direction. To take advantage of better winds in a system it could see fairly clearly? To move away from a passing frigatebird? Can't do more than speculate when lacking basic information such as the synoptic charts for the area during the relevant period.

Why didn't it pitch into Hawaii? Because it didn't need to? There's a clear implication there that it knew where it was going, that it was navigating rather than flying blindly in a direction and hoping for a result.

Finally: Yes, or no. Varies between species: may vary between individuals, or why do we get vagrants that sometimes include adults, though most are juveniles? Are all adult vagrants actually previously displaced juveniles persisting in their new environment?

It's fascinating, no argument from me about that. :t:

John
 
Ouch... 3:) I don't think I was, but there's room for debate.

Yes its big, but its not infinite and there is room for using normal sensory information to correct navigation errors.

As for the very sensible questions:

Dunno why it changed direction. To take advantage of better winds in a system it could see fairly clearly? To move away from a passing frigatebird? Can't do more than speculate when lacking basic information such as the synoptic charts for the area during the relevant period.

Why didn't it pitch into Hawaii? Because it didn't need to? There's a clear implication there that it knew where it was going, that it was navigating rather than flying blindly in a direction and hoping for a result.

Finally: Yes, or no. Varies between species: may vary between individuals, or why do we get vagrants that sometimes include adults, though most are juveniles? Are all adult vagrants actually previously displaced juveniles persisting in their new environment?

It's fascinating, no argument from me about that. :t:

John

Not keen on the passing frigatebird theory ;) - think such a dramatic course alteration would be a bit of an over-reaction even allowing for the low probability of a migrating PGP being troubled by another bird mid-ocean.

I suspect prevailing wind directions might be a much more plausible explanation - the fact is the bird's initial direction of travel (due south) meant it had to alter course at some point. Best guess has to be that it was taking advantage of favourable winds instead of taking the shortest great circle route.

I think we can safely agree that it didn't stop at Hawaii because it didn't have to. What is perhaps more interesting is that it stopped at what appears to be the first available land between Hawaii and NZ. The atoll in question is tiny (less than 10 square kms) with a maximum altitude of 5 metres. It would require an extraordinary feat of navigation to fly 1,700kms over featureless ocean to such a tiny atoll. Was it deliberately heading for a known location, or was it tiring and just pitched down as soon as it saw the first speck of land (perhaps spotting the navigation tower lights from great distance)?

Then there's the apparent round false start along the Aleutian chain before setting off. What's that about?!

All good stuff!
 
Then there's the apparent round false start along the Aleutian chain before setting off. What's that about?!

All good stuff!

Agreed again.... the false start sounds to me like a misjudgement of the deduction to be made from apparent weather conditions and a sensible "abort" decision on realising the mistake. Unlikely to be a realisation that it had left the gas on..... ;)

Cheers

John
 
You guys are thinking from a grounded POV. Last Friday I was bimbling around Southern England with my brother in a Piper Cherokee at a mere 2,500 feet and we could see from Chichester to Exeter from near Salisbury.

Now tell me about the view from 15,000 feet or more and the eyesight of a bird rather than an aging birder.... migrating birds can scan a huge swathe of ocean and have only to vary their course by a degree or so to head for an island a hundred miles out of their way from the distance they can detect it.

Not to mention that even ancient Polynesian sailors recognised that a line of clouds could mean an island generating them: I'm sure birds learn such tricks as well.

I'm not saying its not remarkable. Just that there is less mystery about it than hairless apes with their ground-bound environment think.

John

The ancient Polynesian sailors, and also still some of their present-day descendants, can from the top of the short mast on an outrigger recognise and interpret wave-interference patterns caused by the oceanic swell sweeping past islands.

It has been advanced that pelagic birds and in particular landbirds with long overwater migration routes can also distinguish these interference patterns at, say, FL210, from long down-swell distances and navigate accordingly. Given that godwit and curlew species have demonstrated that many individuals have successfully completed Alaska to Hawaii or New Zealand outward and return migrations many times, it begs the question that it can't be explained....

Likely a suite of endogenous navigational techniques is involved...
MJB
 
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