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ABA list of introduced birds (and where they count) (1 Viewer)

opisska

Jan Ebr
Poland
I still don't understand the rejecting of ship-assisted birds. If the bird lives on the ship on its own, without being put in a cage, where is the problem? Ships are a fact of reality of today's world. With that logic, people should be investigating whether the bird was aided by the presence of roads, railways or high voltage wires in its navigation towards the point of observation. A merchant ship is basically a road over the water, it's just hard to make it fixed.
 

raymie

Well-known member
United States
Some biologists believe that the population of Red-vented Bulbuls in Houston may have been ship-assisted.
 

Julian Thomas

Well-known member
Same in the UK (as Mysticete probably knows already): issues surrounding whether introduced species are self-sustaining (and hence Category C in British terms) and on ship assistance are continual areas of debate. Very few (myself included, I admit) have taken Lady Amherst's Pheasant off their lists, despite it having been on Cat C but died out since. As for Nearctic vagrants, single records of Brown Thrasher and Eastern Towhee in the 1960s remain on the BOU list despite many feeling they could not have made it across without ship assistance, while two Nearctic sparrows I have seen (Song and White-crowned) were on a nature reserve within Liverpool docks, though both have occurred multiple times before and since. A few House Finch records have not made the grade though. As an extreme, BOU did understandably draw the line at the Snowy Sheathbill which came back from the Falklands on board a Navy vessel and was known to have been repeatedly fed by ship's personnel on the trip back.
 

Mysticete

Well-known member
United States
Some biologists believe that the population of Red-vented Bulbuls in Houston may have been ship-assisted.
There is a solid record of Humboldt Penguin from Washington State (or at least I think it is this Penguin), that was considered Ship-assisted, with the idea that some fisherman kept the penguin on board, than released it or it escaped? Such a weird record.
 

RafaelMatias

Unknown member
Portugal
There is a solid record of Humboldt Penguin from Washington State (or at least I think it is this Penguin), that was considered Ship-assisted, with the idea that some fisherman kept the penguin on board, than released it or it escaped? Such a weird record.
Yep, it's crazy, I think it's been published in the Auk or the Condor. I'll dig it up.
EDIT. Wilson's Journal after all: Van Buren, A. N., & Dee Boersma, P. (2007). Humboldt Penguins (Spheniscus humboldti) in the Northern Hemisphere. The Wilson Journal of Ornithology, 119(2), 284–288. here
 

Mysticete

Well-known member
United States
I think it only applies to extirpated non-native populations. The reasoning is that if that introduced population died off, then clearly it wasn't established and should never have been countable.
 

opisska

Jan Ebr
Poland
That's quite absurd imo. You could say the same about vagrants who come to the country and die there ... The lengths people go to not count a bird are sometimes fascinating :)
 

Farnboro John

Well-known member
I think it only applies to extirpated non-native populations. The reasoning is that if that introduced population died off, then clearly it wasn't established and should never have been countable.
Indeed. Though the counter-argument (from BOURC itself I believe) is that the birds remain countable because they were accepted as being self-supporting quite reasonably but then man interfered with (for instance) the amount of available habitat - or even culled the species to extinction - neither contradicting the original committee diagnosis of self-supportingness. It wouldn't of course have anything to do with a committee's institutional inability to deal with possibly having been wrong in the first place (I'm definitely not going there as it does supply the manic lister with an excuse to keep such birds on the list).

John
 

Nutcracker

Stop Brexit!
Indeed. Though the counter-argument (from BOURC itself I believe) is that the birds remain countable because they were accepted as being self-supporting quite reasonably but then man interfered with (for instance) the amount of available habitat - or even culled the species to extinction - neither contradicting the original committee diagnosis of self-supportingness. It wouldn't of course have anything to do with a committee's institutional inability to deal with possibly having been wrong in the first place (I'm definitely not going there as it does supply the manic lister with an excuse to keep such birds on the list).

John
To be fair to the c'ttee, there have been significant changes in the habitat or conditions where the introductions have gone extinct - deliberate eradication for Ruddy Duck, and increased small deer herbivory (also by non-native species!) reducing cover for Lady A's Peasants (and looking like heading the same way for Golden, too). Don't think it's fair to suggest the c'ttee got it wrong the first time.
 

Nightjar61

David Daniels
United States
With its 2014 changes to the Recording Rules, the ABA reversed its previous policy and now allows non-native extirpated exotics to be counted as long as the species was seen when it was on the official checklist.

Dave
 

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