Canada Goose, Cashen Estuary, 30th October (bottom) and 2nd November (top two photos) 2012 (D. Farrar).
Although Canada Geese are commonly kept in wildfowl collections throughout Britain, and they are a relatively common semi-domesticated or feral bird in parts of Ireland, it is still - wild or feral - a rare bird in Co. Kerry. Wild Canada Geese from North America have undoubtedly been recorded in Ireland, though only two have been accepted by the IRBC for Co. Kerry, both at Lough Gill, 2 birds in November and December 1995 and 1 there in January 2005. The species was recently 'split' into generally large, pale 'Canada Goose', and smaller, darker 'Cackling Goose', with several races and intergrades of both (see image below).
The only known source of feral birds in Co. Kerry was the former 'Freshwater Experience' Sanctuary (now the 'Seal Sanctuary') at Trabeg, near Dingle, which kept exotic wildfowl in the early 2000s. 4 individuals which escaped from the Sanctuary in the early 2000s became 18 by 2011 and this flock now roams between Trabeg and Reenard on the Ivearagh Peninsula. Despite their captive origins they are now both elusive and wary in the wild.
The bird above at the Cashen Estuary was found with Whooper Swans in late October, and was wary and 'wild'-looking. It looks a little smaller and perhaps shorter-necked than the classic large, pale-breasted race of most of the feral birds in the British Isles, and perhaps the race 'Interior' is the best guess for the moment, though its true genetics and origins are still unknown.
Have a look at this illustration from the Irish Rare Birds Committee website by Michael O'Keefe (you can click on the illustration for a closer view). It shows roughly the geographical origins of the different races of Cackling and Canada Geese.
There is also an excellent summary of the current difficulties associated with the species on the IRBC page HERE. The final words from that summary are, "Unfortunately, even with the best notes and photos in the world, it is likely some if not many birds will remain unassigned for some time to come."