Bermuda is one of the planet’s best vagrant traps, a completely isolated North Atlantic island about 1045 kilometers ESE of Cape Hatteras, North Carolina. The island’s relatively small size (53 square kilometers) and the absence of other nearby islands surely adds to its power as a vagrant trap. A good system of roads and limited fresh water make the best spots fairly straightforward to check, and a year-round cadre of keen birders are consistently turning up new surprises. That said, few North Americans visit specifically to seek vagrants, largely because it is not included in the ABA Area, which for many in the U.S. and Canada is still the most important listing region. With 361+ species and counting, it certainly deserves more coverage…
The Phylloscopus in the below photos was found by Wendy Frith and David Wingate in the Port Royal/Pompano dump area of Bermuda on 18 February 2014. Andrew Dobson returned the following morning and got these photos. To our knowledge, the calls have not yet been heard or audio recorded. Opinions on the identification have been divided thus far, so we invite Frontiers readers to help nail this one down.
Phylloscopus in North America
Within North America, Arctic Warbler (Phylloscopus borealis kennicotti) breeds in mainland Alaska, and is a common migrant on some Bering Sea islands, such as St. Lawrence Island. All other species are vagrants. Alaska has vagrant records (almost entirely in fall) of Pallas’s Warbler (1), Yellow-browed Warbler (8+), Willow Warbler (11+), ‘Siberian’ Chiffchaff (2-3 records), Wood Warbler (3), Dusky Warbler (20+)–almost all from the western Aleutians, St. Lawrence Island (Gambell), or St. Paul Island (one of the Pribilof Islands). and Arctic Warbler, which breeds. The status of Kamchatka Leaf-Warbler (Phyllscopus examinandus)–not yet split by the American Ornithologists’ Union but clearly deserving of a split since Alstrom et al. (2011)–is not well known but is summarized to the best of current understanding by Howell, Lewington, and Russell (2014). It is at least a rare to casual spring migrant and very rare fall vagrant on the western Aleutians.
Away from Alaska, California has 7 fall records of Arctic Warbler (although some or all of those may refer to Kamchatka Leaf-Warbler) and an impressive 13 Dusky Warbler records, all from fall. Mexico actually has more Phylloscopus species than California, with two records of Dusky Warbler, one of Arctic (or Kamchatka Leaf-Warbler), and one record of Yellow-browed Warbler, all from the Baja California Peninsula. Otherwise, there is but a single sight record of Yellow-browed Warbler from the mid-continent, in Wisconsin. Greenland, a waypoint between Iceland and North America, has one record of Willow Warbler, from Hold With Hope, Myggbukta, 18 Sep 1937 (Boertmann 1994).
Obviously, a record of any Phylloscopus from Bermuda is a highly significant record and a first record for the island. Although a variety of Palearctic shorebirds, herons, waterfowl, and even raptors have appeared here, Palearctic passerine records have been very few. One of the more remarkable was a Dark-sided Flycatcher (Muscicapa sibirica) collected 28 September 1980
Please comment on the ID
With all that in mind, opinions on the identification of this Phylloscopus would be most welcome. Opinions thus far have been divided, so we could use some help from Palearctic birders who have a much better handle on this genus. The Frontiers audience is certainly better suited to comment than almost any other community in the world, so please give us your thoughts, along with supportive field marks that you see in these photos.