[John Cantelo]

Many European & UK birders will be familiar with the concept of 'reverse migration' (although I'm unsure how widely this theory is known elsewhere). This suggests that many Asian rarities turn up in the UK & western Europe as a result of young birds migrating in the opposite direction to that expected (i.e. 180 degrees wrong). However, an article in "British Birds" (James Gilroy & Alexander Lees September 2003) suggested that this theory was flawed. To reduce a complex article to the bare essentials the authors suggest that the apparent concentration of records of rare Asian birds in western Europe more reflects the concentration of birdwatchers there rather than that of rare birds themselves. They suggest that although most young birds depart in the correct direction, in the minority where this navigational trait is faulty, they disperse randomly. Any concentrations in the west being a result of the concentration of birders in western Europe.

Now that paper was a good few years ago so I'm wondering whether the 'reverse migration' idea has now been largely dropped or whether counter arguments have been raised. Also, it seems to me that if 'reverse migration' holds true then it should apply elsewhere in the world. This being an international forum it strikes me as a good place to ask whether it does so,

[Tideliner]

I suspect in part its a case of random dispersal with birds moving north dieing in the sub Arctic , east in the Pacific and only a western route gives any chance of survival, and by chance that route has the highest numbers of people equipped to ID the species are to be found.

[John Cantelo]

Originally Posted by Tideliner

I suspect in part its a case of random dispersal with birds moving north dieing in the sub Arctic , east in the Pacific and only a western route gives any chance of survival, and by chance that route has the highest numbers of people equipped to ID the species are to be found.

This was pretty much the conclusion of the article too,

[MJB]

Originally Posted by John Cantelo

Many European & UK birders will be familiar with the concept of 'reverse migration' (although I'm unsure how widely this theory is known elsewhere).

John,
The various kinds of migration are eloquently discussed in Peter Berthold's excellent book: Berthold, P. 1999. Bird Migration: a general survey. 2nd edn. OUP. Oxford. UK.

What you are discussing is actually called misorientation, reverse migration proper being when home-oriented migration is reversed for a period, usually by inclement weather, but in popular imagination, the way you describe the movements is deeply-rooted!

Kasper Thorup is currently active in bird migration research; he's lead author for the paper:
Understanding the Migratory Orientation Program of Birds: Extending Laboratory Studies to Study Free-Flying Migrants, downloadable here:
http://icb.oxfordjournals.org/conten....full.pdf+html

Perhaps King Richard of Klim knows of recent studies?
MJB

[John Cantelo]

Originally Posted by MJB

John,
The various kinds of migration are eloquently discussed in Peter Berthold's excellent book: Berthold, P. 1999. Bird Migration: a general survey. 2nd edn. OUP. Oxford. UK.

What you are discussing is actually called misorientation, reverse migration proper being when home-oriented migration is reversed for a period, usually by inclement weather, but in popular imagination, the way you describe the movements is deeply-rooted!

Kasper Thorup is currently active in bird migration research; he's lead author for the paper:
Understanding the Migratory Orientation Program of Birds: Extending Laboratory Studies to Study Free-Flying Migrants, downloadable here:
http://icb.oxfordjournals.org/conten....full.pdf+html

Perhaps King Richard of Klim knows of recent studies?
MJB

However inadequate my use of the technical language to describe this idea, it seems that 'reverse migration' has fallen from favour these days. Or at least it seems to have done given the lack of interest in this thread!

[MJB]

Originally Posted by John Cantelo

However inadequate my use of the technical language to describe this idea, it seems that 'reverse migration' has fallen from favour these days. Or at least it seems to have done given the lack of interest in this thread!

John,
The Karup et al paper offers the suggestion that one component of bird migration is the 'stop here' impulse (presumably endogenous), but misoriented birds (having 'reversed' [or set off at any course other than the migration course] their course), may not to have this impulse to stop. The informal understanding is that such birds rarely seem to settle down at the appropriate equivalent distance to the population's wintering location...

What an opportunity for a lucky ringer!

By the way, I must echo your appreciation (in another thread) of Cassowary Lodge and Sue Gregory. On both our visits there, she was enormously enthusiastic and helpful, but we must be the worst dippers - on the two days in different year we were there, the Cassowary did not show (it had the day before and did the day after)! We plan a no-notice visit some time this year...
MJB

[TwoDipsfromAmsterdam]

John

Interesting thread and thanks for starting it. If I recall correctly, Ian Newton stressed in his book, Migration Ecology of Birds, that there were two directions of migration - north-south and east-west. Is there a possibility that individuals that should normally migrate north-south in (northern hemisphere) autumn might somehow adopt an east-west orientation.Not so much reverse migration as sideways migration!

I can't check the book as it's currently packed awaiting our move to the Netherlands next month - a late winter/early spring example of south-west to north-east migration.

David

[Ppedro]

As you say John, would be fascinating to know if ' reverse migration ' holds true elsewhere in the world. Certainly seems a feasable idea to me but obviously not the only way rarities arrive in the UK and Ireland. With advances in sattelite tracking of birds coming on at a fair rate perhaps we will know a lot more for sure in the not to distant future.
Digressing a little, something which has always amazed me regarding visible migration, certainly in the south-west which i am most familiar with, is how maybe hundreds of thousands of birds set of primarily south-west in the first few hours of daylight especially in late autumn. Where have all these birds rested up overnight to flock together so quickly in the morning ?

[DunnoKev]

Originally Posted by MJB

John,
The Karup et al paper offers the suggestion that one component of bird migration is the 'stop here' impulse (presumably endogenous), but misoriented birds (having 'reversed' [or set off at any course other than the migration course] their course), may not to have this impulse to stop. The informal understanding is that such birds rarely seem to settle down at the appropriate equivalent distance to the population's wintering location...

What an opportunity for a lucky ringer!

Ah John, do you remember I wrote on the 'stop here' impulse on another thread regarding the Channel as a barrier to some breeding species? You 'hoo-poed' the idea of it at the time, but perhaps now someone other than me has mentioned this technical aspect you might be just prepared to give a little looksee again??

Originally Posted by John Cantelo

However inadequate my use of the technical language to describe this idea, it seems that 'reverse migration' has fallen from favour these days. Or at least it seems to have done given the lack of interest in this thread!

Oh there's interest, don't wanna be 'hoo-poed' so quickly again Seriously, you could always try posting migration questions in the Migration Forum..

DunnoKev
---------
A very, very, very, very, very, very lucky ringer

[Tideliner]

Kev , I think the stop theory is very likely. I was undertaking a reed warbler study some years ago around a Norfolk gravel pit. By Mid June we had caught and ringed all the resident reed warblers ( about 25 ) when in the second week of July we caught 17 new adult reed warblers 4 were females with brood patches ( showing they had recently bred ) and one female had been ringed in Belgium three days before. The spring had been cold with persistent North winds and I suspect many birds had not attempted to cross the English Channel and bred in N France and Belgium , before heading north to breed again in Norfolk. A friend has retrapped a number of redpolls with brood patches in early May in southern Sweden on the coast. One had been ringed in Italy as a breeding bird in early march. This could be a way in which some birds can enjoy a second spring\\breeding season.

Back to reverse migrants , when we get a big influx of say yellow browed warblers you can follow the reports as they cross the country east to west and then into Ireland. There have even been reports on ships out in the Atlantic. So it looks as though the majority of those warblers still die , but out in the sea on their way to the USA. So it looks as though most of the time its a dead end for the birds , but as blackcaps prove from Central Europe on occasion it works for the birds.

[davercox]

Originally Posted by DavidinParis

If I recall correctly, Ian Newton stressed in his book, Migration Ecology of Birds, that there were two directions of migration - north-south and east-west. Is there a possibility that individuals that should normally migrate north-south in (northern hemisphere) autumn might somehow adopt an east-west orientation.Not so much reverse migration as sideways migration!

I haven't got that book, but in his Collins New Naturalist "Bird Migration" (2010) Newton says (p.304) :
"Another puzzle is that species migrating in an east-west direction seem more likely to reverse their migration than those migrating north-south or northeast-southwest (Thorup,2004)" [the reference is to Thorup,K. Reverse migation as a cause of vagrancy. Bird Study 51: 228-238]
and
"As yet ... mirror-image and reverse-direction migration remain as unproven hypotheses of bird vagrancy. They nevertheless attract strongly-held views on both sides."

[Jane Turner]

In my own head I've always been a little sceptical of using "reverse migration" as opposed to misorientation to account for Siberian vagrants.... but been quite happy to us it to explain neararctic waders and especially autumn records of S.European species in the UK (BW Wheatear, GS Cuckoo etc)