Heads up: Some or all of the identifications affected by this split may have been replaced with identifications of Gelochelidon. This happens when we can't automatically assign an identification to one of the output taxa. Review identifications of Gelochelidon nilotica 144536

Taxonomic Split 132983 (Committed on 31-10-2023)

Gelochelidon macrotarsa is split from Gull-billed Tern Gelochelidon nilotica (Clements 2007:104–105)
Australia now has a breeding endemic tern species with the split of the Australian Tern, which differs from the widespread Gull-billed Tern in numerous often subtle ways. Non-breeders of the two overlap at least from eastern Indonesia to northwestern Australia, though they are often identifiable given adequate views or photos.

eBird/Clements Checklist v2023 (Citation)
Added by donalddavesne on 29 October, 2023 20:11 | Committed by donalddavesne on 31 October, 2023
split into


@thebeachcomber I switch here to not flood the other subject.
I have tweaked the atlas a little to exclude coastal East Queensland from nilotica, as records are very rare there, and the interior since according to ebird nilotica is never found far from the sea.

With these changes, the overlap of both species is for: Indonesia, New Zealand, West Australia (the State), coastal Northern Territories and NW Queensland.
The east coast of Queensland, NSW, Victoria, South Australia and the outback (e.g. Alice Springs) should be macrotarsa only.
With this approach you should end up with approx. 1000 IDs switched to macrotarsa, and 224 in the overlap zone that will become Gelochelidon sp. That's for Australia, and adjacent regions, the rest of the world stays nilotica.
So that means between 100 and 200 obs will become Gelochelidon sp. and will need to be reassessed. Sound acceptable to me...

@birdwhisperer @rjq Would you validate with this split?

Posted by donalddavesne 4 months ago

This one is tricky as there are records of G. nilotica affinis from all around Australia, including in iNat, and it's probably under-reported. The Birdlife map for nilotica has the range extending down the East coast to northern NSW, so I think it is worth extending the atlas for nilotica, though maybe not as far -so I've added the coast as far as Townsville (it's described as regular in Cairns). Hopefully any records in iNat from further south will have been identified as affinis

Posted by rjq 4 months ago

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