The Christmas Sandpiper was apparently restricted to the Kiritimati atoll in Kiribati when it was discovered, described and depicted during the third voyage under the command of Captain James Cook, which visited the atoll from 1777 to 1778; it might very well have once been much wider distributed in the archipelago.
The species disappeared due to the introduction of rats to its home, it might already have been on the brink of extinction when it was first met by Europeans and probably disappeared shortly after.
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Depiction from: ‘Lionel Walter Rothschild: Extinct birds: an attempt to unite in one volume a short account of those birds which have become extinct in historical times: that is, within the last six or seven hundred years: to which are added a few which still exist, but are on the verge of extinction. London: Hutchinson & Co., Paternoster Row, E. C. 1907’
The Northern Pintail (Anas acuta L.) is a holarctic species, which inhabits the whole north of Europe, Asia and North America, as a migrating bird this species can appear almost everywhere, including the remotest islands in the middle of the Pacific Ocean.
The imagination, that, in this way, some of these birds may colonise new and suitable-appearing regions is compelling – and in no way unreasonable.
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The form, discussed here, nearly unknown, and probably invalid by the way, is known only on the basis of three specimens (a male and two females), which were collected on the island of Manra (formerly Sydney Island) in the Phoenix group of Kiribati.
This may have been resident birds, or rather nothing but wintering Northern Pintails in subadult plumage, the author of this form, H. B. Tristram, contemplated about them (On an apparently new Species of Duck (Dafila) from the Central Pacific).:
“The only note I have respecting it is, that there were no Ducks on the island on Mr. Arundel’s arrival, but that afterwards they appeared, and were tolerably numerous for a time. I gather from this remark that it is probably a migrant from one island to another, and a glance at the position of Sidney Island on the map will show that a Duck may enjoy a considerable range of migration in those regions, without necessarily coming under the eye of a collector.”
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However, see also David W. Steadman (Extinction and Biogeography of Tropical Pacific Birds).:
“… Other resident ducks, currently unknown, probably have been lost since human arrival. Perhaps the northern pintail Anas acuta, with more migrant records in Oceania than any other temperate species of duck … developed resident populations on some remote islands. …”
So, as mentioned before, this form is perhaps invalid respectively identical with the nominate race – but it shall be mentioned here for the sake of completeness, and not least as a kind of anticipation for all prospectively to be discovered, extinct duck forms, which certainly have existed on many islands of the Pacific Ocean.
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References:
[1] H. B. Tristram: On an apparently new Species of Duck (Dafila) from the Central Pacific. Proceedings of the Zoological Society of London 79-80. 1886 [2] David W. Steadman: Extinction and Biogeography of Tropical Pacific Birds. University of Chicago Press 2006
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Depiction from: ‘H. B. Tristram: On an apparently new Species of Duck (Dafila) from the Central Pacific. Proceedings of the Zoological Society of London 79-80. 1886’
The Fanning Reed Warbler was originally described in 1883 as a full species but was later recognized as a subspecies of the Kiribati Reed Warbler, which is endemic to the giant Kiritimati atoll in the Line Islands group of Kiribati.
The Fanning Reed Warbler appears to inhabit two atolls north of Kiritimati, namely Tabuaeran and Teranina, it was originally described from Tabuaeran which was called Fanning Island at that time.
The reed warbler is now extinct on Tabuaeran but still inhabits Teraina, where it may even be quite common.
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The taxon is just discussed here because the birds from Tabuaeran and Teraina differ from each other insomuch that the upperparts of birds in fresh plumage from Tabuaeran apparently showed broad white fringes, giving them the appearance of being dusted with flour, while birds from Teraina are not known to show such white fringes and thus more closely resemble the nominate from Kiritimati.
In my opinion the birds from Teraina may in fact prove to be subspecifically distinct from those from Tabuaeran, making the ssp. pistor being extinct and leaving the Teraina birds unnamed. But this has apparently not yet been tested.
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References:
[1] David Pearson; Peter Kennerly: Reed and Bush Warblers. Christopher Helm 2009
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Depiction from: ‘H. B. Tristram: On the Position of the Acrocephaline Genus Tatare, with the Descriptions of two new species of the Genus Acrocephalus. The Ibis 5(1): 38-46. 1883’
