I've been wondering how long do most UK rarities survive upon finding themselves in these islands? Obviously there will be major differences between taxa/species - you would expect say a Vega Gull to survive quite happily for years, whereas a Tanager spp. might not last more than a few days or weeks. I'd imagine predation and climate to be very significant risks for smaller species and that most would succumb quite quickly, but what about the more mobile and/or adaptable? I'm intrigued by how long something like eg. the famous Hebridean white-throated needletail might have survived had it not collided with the wind turbine, and where it might have gone...
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Life expectancy of most rarities? (1 Viewer)
- Thread starter Patudo
- Start date
Farnboro John
Well-known member
The answer could be quite complicated.
There is no reason to suppose that attrition of rare vagrants is higher than, for instance, regular migrants that only pass through and are on their first migration, so potentially unfamiliar with risks away from their natal area.
On the other hand, rarities may have come from further away and made flights at the limit of their abilities, becoming weakened: but after a few days feeding up the status quo may well have been restored.
Most vagrants are themselves migrants that are off course for any of several reasons, weather being the most quoted but not necessarily the most significant. This means that once they have restored their reserves, they may well be on their way again: so a disappearing vagrant does not equal a dead one...
It's a more interesting and perhaps more significant subject for discussion and study than some might think.
John
I feel bad I don't have more time to contribute to the OP since, as John said, there's no straightforward answer. Black & White Warbler and Pale-legged Leaf Warbler have hit windows and died after 3,500 to 5,000 mile journeys (probably not all at once in the latter case!); Grey-cheeked Thrushes have been washed off rocks and taken by cats within hours of arrival on our shores. On the other hand a Northern Waterthrush once survived six months through a British winter and a Black-browed Albatross once returned for twenty years.
The short answer is: there isn't one.
dantheman
Bah humbug
Exhausted migrants (vagrants) the ones we hear about, and yes some of those don't last long!
The majority we don't see or larger waders, waterfowl etc presumably could last for years, yep ...
On the basis that many rarities are 1st winter birds (slightly more prone to getting lost?) and many birds (smaller passerines especially) don't survive a second year imagine the figures are similar once they've fed up and continued 'normally' as John says ...
Something like a Tanager in the OP would presumably re-orientate and head south (again) - whether it would successfully cross to sub-saharan Africa (and return) perhaps we'd never really know but no reason why not ...
Andy Adcock
Worst person on Birdforum
New World Cuckoos always die, much is going to depend on food source available.
Paul Chapman
Well-known member
There are a couple of ringing recoveries of vagrant passerines I believe. Of course, the modern popular theory of random vagrancy and adoption of new wintering areas/strategies would suggest decent survival rates of Eastern passerines.
All the best
All the best
Seem to recall one of the very early Dusky Warblers being picked up dead in Ireland 18 months after being ringed in Wales? Or something like that. Might have only been 9 months, but significant to the OP.
Had a few moments to Google search and refresh my memory and came up with this:
According to David Cottridge and Keith Vinicombe in "Rare birds of Britain and Ireland - A Photographic Record" (1996), that Dusky Warbler, that you refer to, was ringed on the Calf of Man on the 3rd of May 1970, and then found dying near Limerick the following December. Although apparently people at the time assumed that the bird must have spent the intervening summer in Western Europe somewhere, the authors of the book theorise that the bird could have been a 'reverse migrant' (i.e. one which does its migration 180 degrees in the wrong direction (compared to most of its population) which had gone back to Siberia for the summer (having wintered in the Britsh Isles for the winter of '69/'70), and then come back again to winter in Ireland before perishing in Limerick in December 1970.
kb57
Well-known member
Can't remember if it was on Bird Forum or Twitter, so apologies for not posting a link, but I read recently about a colour ringed knot seen in the Azores, originally ringed in Wales I think, which managed to make it back to its former wintering location the following year.
This at least demonstrated a re-orienting capacity for birds which have gone fairly drastically astray.
This at least demonstrated a re-orienting capacity for birds which have gone fairly drastically astray.
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