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Objections to ship assisted birds to the British list? (1 Viewer)
- Thread starter KenM
- Start date
Paul Chapman
Well-known member
The guidelines are attached. The species needs to be considered capable of vagrancy on its own account and no evidence of artificial shelter, feeding, etc.
All the best
Paul
KenM
Well-known member
Thanks Paul, will deliberate later. :t:
Andy Adcock
Worst person on Birdforum
Yep, so all you smug sods with Golden-winged Warbler on your list can take that off for a start.....
Seaforth Song Sparrow has to have a question over it as well?
Here's a hypothetical, if e.g the Song Sparrow was on a grain carrying ship and fed on naturally spilled grain, is that artificial sustenance?
KenM
Well-known member
As I understand it...a “helping hand” ie ship assistance is a no no!
However birds that have been introduced and form “self sustaining” populations are kosha.
Having trouble reconciling this with the former, as has been demonstrated over past millennia, all manner of organisms (plants with host species) and various mammals, fish and invertebrates have been introduced and have become established. A distinct lack of purity in UK flora and fauna then?
One could introduce a veritable plethora of organisms to these shores and they would profligate!
Point being...what is so pivotal about “self sustaining”, surely a ship assisted mig deserves more merit than species deliberately introduced for ornamental collections, sport, falconry or for whatever other reason?
Just saying......
However birds that have been introduced and form “self sustaining” populations are kosha.
Having trouble reconciling this with the former, as has been demonstrated over past millennia, all manner of organisms (plants with host species) and various mammals, fish and invertebrates have been introduced and have become established. A distinct lack of purity in UK flora and fauna then?
One could introduce a veritable plethora of organisms to these shores and they would profligate!
Point being...what is so pivotal about “self sustaining”, surely a ship assisted mig deserves more merit than species deliberately introduced for ornamental collections, sport, falconry or for whatever other reason?
Just saying......
Paul Longland
Well-known member
I suspect that the majority of small passerines from the other side of the pond have probably at least put down for a rest on a ship for at least part of their journey. It is a well known phenomena, many birds will seek shelter on boats, especially during inclement weather. How far they hitch a ride for is probably the crux of the matter. for me the test would be if they have been nurtured or left to their own devices to find food etc.
PYRTLE
Old Berkshire Boy
A migrant on a boat being deliberately fed is a no, whereas if that same bird was feeding on genuinely spilled grain would be accepted.
It's the same scenario at a well watched site in North Norfolk that has grain silos. The spilled cereal would attract Buntings, finches etc, and hosted a male Pine Bunting amongst the Yellowhammers and Corn Bunting. This was around 15 years ago. Sadly times and tidier farming no longer means these flocks exist.
Some might suggest feeding a wild bird on a ship is no different to feeding in your back garden.
It's the same scenario at a well watched site in North Norfolk that has grain silos. The spilled cereal would attract Buntings, finches etc, and hosted a male Pine Bunting amongst the Yellowhammers and Corn Bunting. This was around 15 years ago. Sadly times and tidier farming no longer means these flocks exist.
Some might suggest feeding a wild bird on a ship is no different to feeding in your back garden.
Paul Chapman
Well-known member
It appears that this thread is operating entirely independently to the rules I posted or deliberately some are just making up their own positions.........
"Ship assistance is not necessarily a bar to inclusion on the British List, provided the bird was not confined, sheltered or provisioned during its journey."
"The Committee recently amended the wording of its policy on ship assistance to reflect better the Committee's views, as follows:
That the species might be expected to arrive in Britain naturally and without ship assistance (ie the species is migratory and its migratory route matches that of other species believed to occur naturally)."
So for instance White-throated Sparrow at Fagbury or Song Sparrow & White-crowned Sparrow at Seaforth or indeed Crested Lark at Landguard are fine unless there is evidence that those individuals were caged, sheltered or fed on the journey and the species is capable of getting here unaided. It is the latter aspect that led to review of the Thrasher, Towhee, Lark Sparrow, etc with the conclusion that they could make it unaided.
If news broke today of a Magnolia on a boat half way across the Atlantic as long as it was not caged, sheltered or fed on the journey it would be acceptable on arrival at Southampton docks. The Catbird that did that and then toured the Med was fed on biscuits so it was not accepted.
All the best
So the lesson for budding twitchers aboard a UK-bound vessel with vagrants aboard, be surreptitious as to how you feed those birds - direct feeding ("provisioned") is to be frowned upon, but all hunky-dory with the accidental dropping of part of your lunch :t:
lewis20126
Well-known member
Has this actually been reviewed by BBRC/BOURC? I know it's been discussed on here many many times, but they do anything by way of formal review?
cheers, alan
Farnboro John
Well-known member
"The Committee recently amended the wording of its policy on ship assistance to reflect better the Committee's views, as follows:
That the species might be expected to arrive in Britain naturally and without ship assistance (ie the species is migratory and its migratory route matches that of other species believed to occur naturally)."
Exactly how does Ancient Murrelet fit into this scenario? Or Long-billed Murrelet? Actually you can use the first as support for the second, but applying that policy to the first is nonsensical, and makes a nonsense of the policy. Neither of these birds have a migratory route by which they might be expected to arrive in Britain naturally. The committee's views are unsustainable.
The trouble with the policy, at bottom, is that it demands the proof of a negative. There is no positive evidence for unassisted vagrancy of any Nearctic passerine: even multiple arrivals are only circumstantial evidence. And while there is evidence for a few species of ship-assistance outwith the terms of the policy, that is not evidence that individuals not observed to be fed en route (including those only seen on discovery in the British Isles) weren't - or were......
The species range of presumed genuine Nearctic vagrants currently includes butterflies, dragonflies, kinglets, rails and eagles, as well as no-brainers like wildfowl, gulls and shorebirds. Given this it is pretty much impossible to believe anything can't make it at some point, and the committees are hoist with their own petard: they have accepted so much that now they have no right to deny anything that is not an obvious escape.
John
That the species might be expected to arrive in Britain naturally and without ship assistance (ie the species is migratory and its migratory route matches that of other species believed to occur naturally)."
Exactly how does Ancient Murrelet fit into this scenario? Or Long-billed Murrelet? Actually you can use the first as support for the second, but applying that policy to the first is nonsensical, and makes a nonsense of the policy. Neither of these birds have a migratory route by which they might be expected to arrive in Britain naturally. The committee's views are unsustainable.
The trouble with the policy, at bottom, is that it demands the proof of a negative. There is no positive evidence for unassisted vagrancy of any Nearctic passerine: even multiple arrivals are only circumstantial evidence. And while there is evidence for a few species of ship-assistance outwith the terms of the policy, that is not evidence that individuals not observed to be fed en route (including those only seen on discovery in the British Isles) weren't - or were......
The species range of presumed genuine Nearctic vagrants currently includes butterflies, dragonflies, kinglets, rails and eagles, as well as no-brainers like wildfowl, gulls and shorebirds. Given this it is pretty much impossible to believe anything can't make it at some point, and the committees are hoist with their own petard: they have accepted so much that now they have no right to deny anything that is not an obvious escape.
John
KenM
Well-known member
Yes apologies Paul, I completely forgot to read the attached file, as I was prompted by your quote above, and steamed in (no pun intended).
One might be forgiven for interpreting the said “quote” above as not being supportive of e.g Red-breasted Nuthatch, which was clearly ship-assisted, irrespective of whether it was fed en-route (unlikely) or not, a bird of this taxa with what might appear having “physical flight limitations” to succeed a transatlantic crossing...even with hurricane/ship assistance most unlikely?
Cheers
lewis20126
Well-known member
Well not quite. The occurrence of North Pacific 'seabirds' in Western Europe was established even prior to the 1990 Ancient Murrelet, eg by Aleutian Tern in 1979 and (I think) a Crested or Parakeet Auklet at some other location. And of course it's all been proved to be a well established vagrancy pattern (Tufted Puffin, two Long-billed Murrelets inc Romania, GW/SB Gulls various) so I cannot see how this contradicts the point that 'the species is migratory and its migratory route matches that of other species believed to occur naturally', if you extend migratory to 'dispersive' in the case of Alcids.
cheers, alan
Farnboro John
Well-known member
Being aware of the range of Pacific Alcids that have occurred in Europe I thought you might suggest this. Because of the nature of the migrations of each of these seabirds, what you have just said is that provided a species is migratory, it doesn't matter what direction the migration takes. It is the propensity for migration that generates the capacity for vagrancy: migrational directionality (as well as actual distance of start and finish point from the British Isles) is essentially irrelevant. Which still supports the hypothesis that anything that moves can turn up: while the actual variety of what has turned up shows that it is impossible to rule anything out on flight capacity, because the weather variables can compensate for the limitations of the creature.
Naturally this is all applicable to dispersion as well, and the range of species dispersing is wider than that of species migrating.
Which is all good news for the twitcher suffering from diminishing returns: the species options for future vagrancy from the Nearctic at least are considerable.
John
lewis20126
Well-known member
Have a look at records of Long-billed Murrelets across North America - at first glance, it is really quite amazing but then you realise what it tells you about the ability of this species to travel great distances. I'm not sure we know much about the 'normal movements' of most North Pacific seabirds anyway - how far do Glaucous-winged Gulls migrate in winter? Probably nothing like the distance of any likely route to NW Europe.
cheers, alan
Paul Chapman
Well-known member
Yes - announced formal review in 2006 and announced retained in Category A in 2012. 41st Ibis report attached.
All the best
Paul
lewis20126
Well-known member
Thanks - I'd not picked up on that - or forgotten. Interestingly ambiguous comments:
Transatlantic vagrants
BOURC reviewed the records of four species
accepted onto Category A before the adoption of the
current guidelines for assessment of potentially shipassisted
birds. These species were Northern Mockingbird
Mimus polyglottos, Brown Thrasher Toxostoma rufum,
Eastern Towhee Pipilo erythrophthalmus and
Lark Sparrow Chondestes grammacus. All were
retained in Category A. BOURC’s guidelines for treatment
of potentially ship-assisted birds were reviewed
and remain unchanged. It was noted that Europewide
consensus on the treatment of ship-assisted
transatlantic vagrants would be highly desirable.
It doesn't say whether these four species were tested against the guidelines.
cheers, alan
