Woodpigeons Autumn 2014 (1 Viewer)

[PaulD]

If you are happy that the only plausible explanation for the large numbers of Wood Pigeons migrating over Britain in the autumn is an influx of continental birds then fine, but I will have to disagree.

We have a breeding population of 5.3 million pairs so the autumn population is probably over 15 million and could easily be over 20 million; that's more than enough to account for the numbers seen on migration.

I agree that Wood Pigeons often move at a great height, but it's not safe to assume that these are continental birds. The possibility that British birds will also move at great height cannot be dismissed; what evidence makes you sure that these aren't birds from further north in Britain?

It's clear that the authors of the latest Bird Atlas 2007-11 don't share your conviction as they note that “the degree of integration between populations within Britain & Ireland or between Britain & Ireland and continental Europe is uncertain”.

I would be much more comfortable with the idea of significant numbers of continental Wood Pigeons reaching Britain if this movement was being detected on the east coast, but it isn't. We know that Wood Pigeons can be forced down by bad weather and the Swedish study I quoted showed that they could be drifted by wind conditions.

That being the case it's reasonable to expect falls to occur on the east coast, but the evidence is very limited:-
Fair Isle – less than 50 per year
Spurn Report 2012 “autumn passage was again light” and 2013 “autumn passage was almost non-existent”.
Another observer said that checking the 'Scottish Bird Reports' from 1968 to 2000 produced “a mere handful of records of small numbers of the species at likely migratory spots, and in some years none at all”.

You suggest that the lack of east coast records is because they overfly it at great height, but a scenario where they always avoid being grounded by bad weather is highly unlikely. Falls happen regularly with thrushes for example and it would be inevitable that occasionally Wood Pigeons would set off in good weather conditions and then encounter a rain bearing front as they approached Britain and be forced down.

With regard to flight times and the suggestion that birds leaving Scandinavia at dawn will arrive here in the dark:-

Norway to Shetland 330 kms = 5.5 hours flying time
Norway to NE Scotland 450 kms = 7.5 hours flying time
Esbjerg to Spurn Point = 560 kms = 9 hrs 20 mins
Daylight on 1st Nov in Denmark = 9 hours 29 mins.

Please also bear in mind that I did not ignore the single Norwegian and Danish ringing recoveries – I mentioned them in posts #14 and 16. However single records are of limited value, so I contacted the Norwegian ringing office who have supplied the following link:-

http://must.ringmerking.no/viskartm...d=NO&pxFunnSted=ALL&pxArtNr=06700&pxTidsrom=3

The single British record was (in their words) “an old, slightly odd record of a 2nd year bird shot in August 1965”.

It's noticeable that there are no ringing recoveries in Iberia and that clearly reduces the need for flights over Southern England. Based on the evidence of ringing recoveries it's clear that the quickest route for most Norwegian Wood Pigeons to reach their wintering grounds will not involve flying over Britain.

 

[Farnboro John]

If you are happy that the only plausible explanation for the large numbers of Wood Pigeons migrating over Britain in the autumn is an influx of continental birds then fine, but I will have to disagree.

We have a breeding population of 5.3 million pairs so the autumn population is probably over 15 million and could easily be over 20 million; that's more than enough to account for the numbers seen on migration.

I agree that Wood Pigeons often move at a great height, but it's not safe to assume that these are continental birds. The possibility that British birds will also move at great height cannot be dismissed; what evidence makes you sure that these aren't birds from further north in Britain?

It's clear that the authors of the latest Bird Atlas 2007-11 don't share your conviction as they note that “the degree of integration between populations within Britain & Ireland or between Britain & Ireland and continental Europe is uncertain”.

I would be much more comfortable with the idea of significant numbers of continental Wood Pigeons reaching Britain if this movement was being detected on the east coast, but it isn't. We know that Wood Pigeons can be forced down by bad weather and the Swedish study I quoted showed that they could be drifted by wind conditions.

That being the case it's reasonable to expect falls to occur on the east coast, but the evidence is very limited:-
Fair Isle – less than 50 per year
Spurn Report 2012 “autumn passage was again light” and 2013 “autumn passage was almost non-existent”.
Another observer said that checking the 'Scottish Bird Reports' from 1968 to 2000 produced “a mere handful of records of small numbers of the species at likely migratory spots, and in some years none at all”.

You suggest that the lack of east coast records is because they overfly it at great height, but a scenario where they always avoid being grounded by bad weather is highly unlikely. Falls happen regularly with thrushes for example and it would be inevitable that occasionally Wood Pigeons would set off in good weather conditions and then encounter a rain bearing front as they approached Britain and be forced down.

With regard to flight times and the suggestion that birds leaving Scandinavia at dawn will arrive here in the dark:-

Norway to Shetland 330 kms = 5.5 hours flying time
Norway to NE Scotland 450 kms = 7.5 hours flying time
Esbjerg to Spurn Point = 560 kms = 9 hrs 20 mins
Daylight on 1st Nov in Denmark = 9 hours 29 mins.

Please also bear in mind that I did not ignore the single Norwegian and Danish ringing recoveries – I mentioned them in posts #14 and 16. However single records are of limited value, so I contacted the Norwegian ringing office who have supplied the following link:-

http://must.ringmerking.no/viskartm...d=NO&pxFunnSted=ALL&pxArtNr=06700&pxTidsrom=3

The single British record was (in their words) “an old, slightly odd record of a 2nd year bird shot in August 1965”.

It's noticeable that there are no ringing recoveries in Iberia and that clearly reduces the need for flights over Southern England. Based on the evidence of ringing recoveries it's clear that the quickest route for most Norwegian Wood Pigeons to reach their wintering grounds will not involve flying over Britain.

Thank you for a very comprehensive response. However, your response still fails to fit the facts, the principal one being that 34,000 ringing recoveries of British Woodpigeons provide hard evidence that they do not move at all, the average (mean presumably) being just 5km (Your post #9). In the face of this quantity of evidence you have no choice but to look elsewhere for explanation. You cannot credibly continue to try to have it both ways. British Woodpigeons, by ringing evidence, do not move, full stop, end of story.

Your present statement that there are no ringing recoveries from Iberia is contradicted by your post #14 in which you quote BWP: "Numerous ringing recoveries from Scandinavian populations show they winter mainly southwest France and (especially) Iberia" so what is it that you actually believe?

BTW in hard evidence (which is what ringing recoveries are, I think that is common ground between us) there are no "old, slightly odd records" just ones that haven't been explained. Funnily enough this one fits the explanation I am offering, which also fits the observation over ten years of the animals. Even the fact that it was a second year bird, on its second autumn migration, indicates it was most likely going exactly where it meant to: but for reasons unknown had to drop down and was shot by our enthusiastic hunting clique. The other observation, that well across the UK movement is invariably early to mid morning, indicates quite obviously that the birds don't dump down at the coast.

No falls - although if you want a coastal site that holds large numbers of Woodpigeons in late autumn and early winter, the Isle of Sheppey is a good place to look. That was on the coast, last time I was there, just devoid of an observatory. Not surprising they don't feel the need to drop immediately really, they are not far behind Eider in terms of speed, power and one rather suspects, endurance: they certainly look like it when moving! Going up to 10,000 feet or perhaps higher, they may well overfly bad weather a lot of the time. Only real storms will reach up enough to give them pause. Of course if the are flying above the cloud, observers aren't going to see them..... Thrushes etc fly much lower (hence you can hear them overnight) and are much more likely to be stopped dead by quite insignificant cloud and rain. Having reached the barren coast they head inland and drop down where they can see feeding opportunities (as suggested by inland Scottish observers in one or other of the Woodpigeon migration threads).

I note also that your scan of migration reports does reveal a belief in passage from outside UK, albeit minor. I suggest to you that the reason is that Woodpigeons are tremendous fliers and not easily baulked or diverted. Having watched one outfly a Peregrine in open sky, I know this very well.

Cheers

John

 

[Nutcracker]

That being the case it's reasonable to expect falls to occur on the east coast, but the evidence is very limited:-
Fair Isle – less than 50 per year
Spurn Report 2012 “autumn passage was again light” and 2013 “autumn passage was almost non-existent”.
Another observer said that checking the 'Scottish Bird Reports' from 1968 to 2000 produced “a mere handful of records of small numbers of the species at likely migratory spots, and in some years none at all”.

Scotland and northern England aren't relevant; they are well off route for any bird travelling from Scandinavia to either western France or Iberia (see below). Had they been going to Ireland (as the wintering thrushes are mainly doing), then Scotland would be relevant, but they aren't. The places to check for incoming birds would be the coasts of East Anglia and Kent.

 

[bitterntwisted]

What does that line look like when the curvature of the earth is taken into account and it's redrawn as a great circle from, say, centre of Finland to Galicia?

 

[Nutcracker]

What does that line look like when the curvature of the earth is taken into account and it's redrawn as a great circle from, say, centre of Finland to Galicia?

That's printscreened from google earth, so it is a great circle line

 

[dantheman]

What does that line look like when the curvature of the earth is taken into account and it's redrawn as a great circle from, say, centre of Finland to Galicia?

I had a quick look on a globe this morning and given the short distance involved I couldn't really see a discernible difference that would push it further west imo.


An interesting thread, arguments put forward from both camps could well be correct .

I can't see two sea crossings being a great strategy as a matter of course. If continental Woodpigeons don't overwinter here I would be a bit surprised though. Common Crane (ok totally different) also very rarely hit our shores yet may share a similar flight path?

Agree that the picture in Kent/East Anglia may be more relevant. Wonder what the picture is on the south coast eg Portland Bird Obs/Scillies - they get Woodpigeon flocks, but are they observed flying out to sea? (And are they 'just' British?)

Seem to recall flocks of Woodpigeon migrating south in lowland south-central France at relatively low level, and can't say this was in particularly bad conditions. Of course these could just have been local birds 'setting off' - they weren't mega thousands.

 

[Nutcracker]

I can't see two sea crossings being a great strategy as a matter of course.

It obviously has risks, but also some benefits, like reduced risk of meeting predators, and maybe also a lower risk of running into large thunderheads (which develop more easily over land).

 

[PaulD]

I am happy to accept that the British ringing records don't “gel” with field observations; perhaps this is as John suggested an illustration of the limitations of bird ringing. However I share with the authors of the Bird Atlas a belief that what exactly is happening with British and continental populations is uncertain.

There is no contradiction between my comment about the lack of ringing recoveries from Iberia and post #14 where I quote from BWP. The former referred just to Norway, but the latter was referring to the whole of Scandinavia. There are no Norwegian ringing recoveries from Iberia, but there are recoveries from elsewhere in Scandinavia.

In fact I have received details from the Danish ringing office and their pattern of recoveries (see the attached) is very similar to the Norwegian one. Birds were recovered from Germany, Holland, Belgium, France, Spain and Ireland. However there is just one Irish recovery and two Spanish ones (both of the latter were towards the western end of the Spanish Pyrenees and had barely penetrated into Spain).

The single Norwegian and Danish recoveries seem to me insufficient evidence to demonstrate a pattern of continental birds migrating through Britain. John describes the Norwegian bird as being on its second autumn migration when it was shot, but that is speculation not fact. It was shot on the 7th August and Wood Pigeons are late migrants which don't start moving until early October, so it was two months before their migration season begins and the Norwegian ringing office have described it as a summer (not autumn) recovery. Other scenarios are quite possible e.g. it arrived the previous autumn, wintered here, mated with a British bird and didn't return to Norway.

The ringing recoveries from Norway and Denmark describe wintering grounds which stretch from Denmark in a southwesterly direction to the extreme north of Spain. That being the case the incentive for them to overfly Britain is limited. The largest British counts come from Gwent, Dorset and Yorkshire, but for large numbers of Norwegian and Danish Wood Pigeons to head for their wintering grounds via Gwent and Yorkshire would be surprising. And of course there is no evidence that they do.

That's why the evidence from Spurn is relevant and Fair Isle is also relevant because a link has been provided to large numbers of Wood Pigeons grounded in Scotland by bad weather, which was in turn linked to unusual spring numbers on Fair Isle. Wood Pigeons are powerful flyers, but as the above incident and the one I described from Trektellen show, they can be grounded by bad weather, so it is reasonable to expect occasional arrivals/falls of continental Wood Pigeons along the east coast, but they don't really occur. Spurn doesn't get them and I've got Norfolk Bird Reports for 2001, 2003, 2005 and 2006 and there is nothing significant.

I have a copy of the Isles of Scilly Bird Report for 2005 and that is interesting. It notes that numbers in 2005 were unexceptional, but comments that “In some years, though, passage is abundantly clear as vast freshly arrived flocks circle high above the islands like a cloud, eventually dropping into wooded areas such as Tresco Great Pool”. That doesn't gel with ringing information from the UK or indeed Denmark or Norway and more information would be welcome.

That pretty much brings me back to the opening point that what exactly is happening with British and continental populations is uncertain.

 

[Farnboro John]

I am happy to accept that the British ringing records don't “gel” with field observations; perhaps this is as John suggested an illustration of the limitations of bird ringing. However I share with the authors of the Bird Atlas a belief that what exactly is happening with British and continental populations is uncertain.

There is no contradiction between my comment about the lack of ringing recoveries from Iberia and post #14 where I quote from BWP. The former referred just to Norway, but the latter was referring to the whole of Scandinavia. There are no Norwegian ringing recoveries from Iberia, but there are recoveries from elsewhere in Scandinavia.

In fact I have received details from the Danish ringing office and their pattern of recoveries (see the attached) is very similar to the Norwegian one. Birds were recovered from Germany, Holland, Belgium, France, Spain and Ireland. However there is just one Irish recovery and two Spanish ones (both of the latter were towards the western end of the Spanish Pyrenees and had barely penetrated into Spain).

The single Norwegian and Danish recoveries seem to me insufficient evidence to demonstrate a pattern of continental birds migrating through Britain. John describes the Norwegian bird as being on its second autumn migration when it was shot, but that is speculation not fact. It was shot on the 7th August and Wood Pigeons are late migrants which don't start moving until early October, so it was two months before their migration season begins and the Norwegian ringing office have described it as a summer (not autumn) recovery. Other scenarios are quite possible e.g. it arrived the previous autumn, wintered here, mated with a British bird and didn't return to Norway.

The ringing recoveries from Norway and Denmark describe wintering grounds which stretch from Denmark in a southwesterly direction to the extreme north of Spain. That being the case the incentive for them to overfly Britain is limited. The largest British counts come from Gwent, Dorset and Yorkshire, but for large numbers of Norwegian and Danish Wood Pigeons to head for their wintering grounds via Gwent and Yorkshire would be surprising. And of course there is no evidence that they do.

That's why the evidence from Spurn is relevant and Fair Isle is also relevant because a link has been provided to large numbers of Wood Pigeons grounded in Scotland by bad weather, which was in turn linked to unusual spring numbers on Fair Isle. Wood Pigeons are powerful flyers, but as the above incident and the one I described from Trektellen show, they can be grounded by bad weather, so it is reasonable to expect occasional arrivals/falls of continental Wood Pigeons along the east coast, but they don't really occur. Spurn doesn't get them and I've got Norfolk Bird Reports for 2001, 2003, 2005 and 2006 and there is nothing significant.

I have a copy of the Isles of Scilly Bird Report for 2005 and that is interesting. It notes that numbers in 2005 were unexceptional, but comments that “In some years, though, passage is abundantly clear as vast freshly arrived flocks circle high above the islands like a cloud, eventually dropping into wooded areas such as Tresco Great Pool”. That doesn't gel with ringing information from the UK or indeed Denmark or Norway and more information would be welcome.

That pretty much brings me back to the opening point that what exactly is happening with British and continental populations is uncertain.

I will hold my hand up to having jumped too hard on the Norwegian ringing recovery. Thinking afterwards I too could think of the scenarios you describe. Sorry!

However, the deeper we go into the field observation evidence, the more obvious it is that, having established through a large quantity of ringing evidence that the British Woodpigeon population is mostly too fat to fly, there is also a large body of field observer evidence from all over the country but chiefly in the Southern half, that what by elimination must be Continental Woodpigeons - and further must by all reasonable supposition be Scandinavian, since Central European birds have no reason to cross water at all, its not in their way - cross Britain en route to their wintering grounds in Western Europe.

One question that might be answered by ringing records is: do Spanish hunters ever provide ringing evidence? Are there quarry species for which Spain has provided a lot of ringing evidence? If Spanish hunters (except for one or two) simply remove rings and bin them prior to cooking up pigeon paella, then no amount of ringing will ever demonstrate Woodpigeon movement in and out of Iberia.

I think it unreasonable in the extreme to say that what is happening is "uncertain". Using all the evidence available to us actually it is pretty obvious. Its only by trying to depend on ringing alone that one comes up against a blank wall.

John

 

[PaulD]

John

I envy your confidence in saying that what is happening is pretty obvious. If you look for positive evidence of continental Wood Pigeons then there is very little available.

Why are there so few coastal falls/arrivals? The only ones mentioned in this discussion are Fair Isle in spring and the Scillies in autumn. The latter is only 40kms from the mainland and if Wood Pigeons land there after only 40 kms of open water then it undermines the suggestion that they pass over our coasts at such a great height that they escape detection.

Thousands of Wood Pigeons are seen flying south across Scotland and Northern England in autumn. If they are continental birds where are they entering the country and why are they choosing a longer, more hazardous route involving two sea crossings when a shorter continental route is available? The answer isn't obvious to me.

A widespread reverse movement is noted in the early winter with birds flying north. Numbers are lower than the autumn though including counts of over 10,000 in a day at some sites. Are these continental or British birds? Again the answer isn't obvious to me.

It's surprising, but also fascinating, that there are so many unanswered questions about a very common bird which is a serious agricultural pest.

 

[Nutcracker]

If you look for positive evidence of continental Wood Pigeons then there is very little available.

Problem is, there's no evidence of UK Wood Pigeons migrating, either!

... the Scillies in autumn. The latter is only 40kms from the mainland and if Wood Pigeons land there after only 40 kms of open water then it undermines the suggestion that they pass over our coasts at such a great height that they escape detection.

Unless they'd well overshot Scilly, realised things looked bleak ahead, and turned back?

Thousands of Wood Pigeons are seen flying south across Scotland and Northern England in autumn.

Not here [Northumbs], there aren't! Plenty of flocks of resident birds, with no apparent change in numbers through the year, and no modern records of large passage flocks. Interestingly though, there are historical records of large numbers in off the sea, but not in recent times - Bolam [1912] "a compact flock passed over Berwick, at dawn on 30 November 1883, quite half a mile in length and at least 20 yards in width", and again at Berwick, between dawn and 09.00 on 14 November 1884, "an almost continuous succession of flocks, numbering hundreds each, coming up from the sea, and passing high overhead".

If they are continental birds where are they entering the country and why are they choosing a longer, more hazardous route involving two sea crossings when a shorter continental route is available? The answer isn't obvious to me.

Norway to western France, takes you over southern England, as demonstrated above. And sea crossings may be safer, Peregrine and Goshawk-free. The lack of predators at sea was cited as a possibly important factor in the paper about Bar-tailed Godwits going direct from Alaska to New Zealand without Asian stopovers in autumn.

A widespread reverse movement is noted in the early winter with birds flying north. Numbers are lower than the autumn though including counts of over 10,000 in a day at some sites. Are these continental or British birds? Again the answer isn't obvious to me.

Again, no records of this in Northumbs.

It's surprising, but also fascinating, that there are so many unanswered questions about a very common bird ....

Agree there!

 

[Farnboro John]

John

I envy your confidence in saying that what is happening is pretty obvious. If you look for positive evidence of continental Wood Pigeons then there is very little available.

Why are there so few coastal falls/arrivals? The only ones mentioned in this discussion are Fair Isle in spring and the Scillies in autumn. The latter is only 40kms from the mainland and if Wood Pigeons land there after only 40 kms of open water then it undermines the suggestion that they pass over our coasts at such a great height that they escape detection.

Thousands of Wood Pigeons are seen flying south across Scotland and Northern England in autumn. If they are continental birds where are they entering the country and why are they choosing a longer, more hazardous route involving two sea crossings when a shorter continental route is available? The answer isn't obvious to me.

A widespread reverse movement is noted in the early winter with birds flying north. Numbers are lower than the autumn though including counts of over 10,000 in a day at some sites. Are these continental or British birds? Again the answer isn't obvious to me.

It's surprising, but also fascinating, that there are so many unanswered questions about a very common bird which is a serious agricultural pest.

Frankly, Paul, I can't prevent you believing what you like, but I note that your arguments have worn so thin that you are now reduced to scraping up what field observations you can (a little surprising in view of your faith in the infallibility of rings) in order to try to maintain a front of confusion.

However, for the benefit of posterity, I will restate - again - what ringing has proved (note proved - not suggested - not proposed - proved) British Woodpigeons don't move.

Lets take the next step simply. British Woodpigeons don't move, so large/very large movements of Woodpigeons in Britain are from somewhere else. The list of somewhere elses is short. They don't come out of the sea,or off the Arctic icecap, because these places don't have any Woodpigeons (though I have no ringing evidence to support that statement: you will have to take it on trust. :king Where does that leave? Goodness me, the continent of Europe, including, for want of negative evidence, Scandinavia.

Ergo, and regardless of whether or not you can confirm it by ringing recoveries or other means, continental Woodpigeons cross Britain in large numbers in a concentrated broad-front movement early in November each autumn: they do not stop at the coast because they don't need to and they are not stopped by other than major gales and storms: they are not noticed as unusual in the hinterland as the numbers of Woodpigeons there are already very great (evidenced by you).

They are seen coming up from roosts because they are low (evidenced by all the migration counters): they are not seen coasting in or out because they are high (evidence quoted by me earlier).

If Woodpigeons trickle back through the course of the winter -presumably because they are aware of some additional seasonal food availability that I don't know about - then that certainly goes some way to explaining why spring passage is found to be lighter than the concentrations of autumn. It is however a separate question from the specific one about autumn migration, as quite a lot of species don't use precisely the same routes on each, for a variety of reasons.

Suddenly you are quoting thousands of Woodpigeons flying south across Scotland and Northern England, where your previous posts refused to believe in such things. However, you are still not acknowledging that the really big numbers cross the Southern part of the archipelago, and if you can't see yet that "vast flocks" arriving on Scilly are not there for a lads' weekend before returning to their regular haunts in the hinterland of Britain, I really don't know what we are discussing.

There really isn't any confusion in the minds of those of us that get out there and watch birds.

BTW I assure you if Woodpigeon was a serious agricultural pest our dear farmers would have done something about it by now, probably poisoned bait. The fact that they tolerate it for an insignificant amount of shooting is a sure-fire indicator that they are not worried. Next you'll be telling me that British arable farmers live on the breadline and drive thirty-year old Ford Escorts because they can't afford the latest Range Rover Sport.

John

 

[PaulD]

I suspect that this thread has become circular in nature so I'm content to leave it there. I can add one snippet of evidence - a chart from the Spanish ringing website which shows birds recovered in Spain traced back to their country of ringing.

 

[Steve Lister]

I suspect that this thread has become circular in nature so I'm content to leave it there. I can add one snippet of evidence - a chart from the Spanish ringing website which shows birds ringed in Spain traced back to their country of ringing.

Ringed in Spain...............country of ringing? Which is correct Paul?

Either way the birds don't have to fly along the connecting lines, but there again it would make sense if they did as it looks the shortest/easiest route.

Steve

 

[Nutcracker]

I suspect that this thread has become circular in nature

Hope not!

Any thoughts on Bolam's observations? It would be interesting if weather conditions at the time were available (likely not!) to see if there were conditions then that would displace a possible trans-southern-North Sea migration from a normal Norway - southern England - western France route to a more northwestern line.

 

[PaulD]

Ringed in Spain...............country of ringing? Which is correct Paul?

Either way the birds don't have to fly along the connecting lines, but there again it would make sense if they did as it looks the shortest/easiest route.

Steve

Thanks for pointing out the error Steve. It should read "recovered in Spain traced back to their country of ringing". I'll try and edit that.

Agreed that the birds don't have to fly along the connecting lines, but it confirms that the virtual lack of Norwegian and Danish ringing recoveries in Spain isn't because Spanish hunters routinely throw bird rings away.

 

[PaulD]

Any thoughts on Bolam's observations?

There are similar observations in Birds of Yorkshire by Nelson (1907), but I would be wary about placing too much reliance on them. In Birds of Cleveland (2008) Martin Blick wrote that since Nelson's time "About 420 flew inland over Seal Sands on 4 November 1975 but were not actually seen to cross the coastline and at least 1850 flew NW along the coast in four hours on 16 November 1994. Otherwise only single birds have been seen over the sea in recent years."

Make your own mind up whether those large flocks reported coming in off the sea in the 1800s have simply stopped happening or whether they were just flying along the coast and not coming in off the sea at all. Nelson's book includes a lot of really good stuff but it also includes descriptions of skuas chasing each other and snipping the elongated central tail feathers off, and I can't believe that really happened.

 

[Farnboro John]

Thanks for pointing out the error Steve. It should read "recovered in Spain traced back to their country of ringing". I'll try and edit that.

Agreed that the birds don't have to fly along the connecting lines, but it confirms that the virtual lack of Norwegian and Danish ringing recoveries in Spain isn't because Spanish hunters routinely throw bird rings away.

Indeed it does.

So the next question is how many Norwegian Woodpigeons are ringed each year? Because they must go somewhere, one trip to Norway in mid-winter was enough to show me that they can't feed there throughout the winter.

The map shows really quite a lot (good post. Well done).

It shows a total absence of Woodpigeon records from North and West of a a certain line. It also shows a really good consistency in the direction of flight of migrating Woodpigeons - in fact it gets more consistent the further North and West you go, then cuts off. It also shows a huge lacuna in recoveries from North-west Spain.

Now, since we know there are lots of Woodpigeons in Norway and Sweden in summer, and that they all leave, BUT don't show up in the rest of the Woodpigeon corridor, (where we have enough records to validate the data we do have), it is clear they are doing something else.

Given the consistent direction of Woodpigeon migration, it is reasonable to assume they fly in the same direction towards the Iberian peninsula. So, if we take the bearing given by the ringing recoveries and translate it a little to the North-west to indicate Woodpigeons leaving peninsular Scandinavia from the toe-end (and it may be broader-fronted than that) then lo and behold you have a flightpath over Southern Britain to North-west Spain, thus explaining all the data at the same time except why North-western Spaniards don't send rings back (unless of course Norwegians don't put many on.)

John

 

[bitterntwisted]

John's accounts chime completely with my experience of woodpigeon movements (thousands and thousands heading south west from 0700 to 0830 AM in early November 2007 and 2008 while atlas surveying in Beds and Bucks, many in flocks so high that they were invisible without bins) And his account seems the most parsminonious to me. Where is the Norwegian riniging data?

 

[russell toon]

Don't know where the Woodies are coming from or where they end up but very large
numbers move down through the west central side of England. In North Staffs alone we had about 210,000
from the 19 Oct to the 6 Nov this Autumn.
Russell