ML584795781

Age

Not specified

Sex

Not specified

Observation details

First North American record. The plover was smaller than the Gray-tailed Tattler it was first associating with and had clean white undersides and sandy brown uppersides. The bird had a clean white collar that extended around the hindneck and distinct black spurs on the sides of the upper breast. The head was well patterned, with a distinct black feathering behind the eye, a complete black eyeline almost as thick as the bill, a black forecrown bar which contrasted with the overall white face and eyebrow and an obvious orangish-rufous crown that extended to the white collar on the hindneck. The rufous-orange crown was visible at all angles and contrasted with the sandy brown back. The rufous-orange crown seemed most vibrant above the white collar, eyebrow, and forecrown, and became slightly less vibrant closer to the top of the head. The legs were dark. The feathering around the lores on the right side of the bird appeared wet and slightly disheveled giving the appearance of an even wider dark lores. The feathering on the left side of the face appeared normal. In flight, the plover showed overall sandy brown wings and back, with a slightly darker tail and white outer tail feathers. The bird had white bases to the flight feathers that was narrow in the secondaries and larger in the inner primaries giving the bird a distinctive, nearly complete white bar across the upperwing. After the plover flushed silently the first time, I observed it from a distance, and I did not approach as it seemed slightly unsettled in the location it landed. After a few minutes the plover flushed, and it gave three calls as it flew back behind me closer to its original position. The three calls were a clear (not buzzy or raspy) “dip...dip...dip," somewhat reminiscent of a Sanderling. The black upper breast spurs (incomplete breast band), white collar on the hind neck, and rufous-orange crown eliminate most similar looking Charadrius plovers and leave four candidate species: White-faced Plover C. dealbatus Swinhoe, 1870, Malaysian Plover C. peronii Schlegel, 1865, Kentish Plover C. alexandrinus Linnaeus, 1758, and Snowy Plover C. nivosus (Cassin, 1858). The Malaysian Plover is non-migratory and unlikely to be found north of SE Asia and the Philippines, but the uniform sandy brown back from the white collar to the tail is inconsistent with this species which shows pales fringes to mantle feathers and a black collar below the white collar on the hind neck. The White-faced Plover is a migratory plover breeding in China and wintering in SE Asia that would not show the thick distinct black eyeline, bold and thick black forecrown, bold black upper-breast spur, and black ear-patch that are present on the Shemya plover. All those features would be absent or subdued in White-faced Plovers (Kennerly et al. 2008). The final two species, Kentish and Snowy Plover, are closely related and were lumped by the American Ornithological Society in 1944 and then re-split in the fifty second supplement of the Check-List of North American Birds based on recommendations from Küpper et al. 2009. The Snowy Plover is the New World counterpart of Kentish Plover and has previously occurred in Alaska (Gibson et al. 2023). While plumage features can overlap between Snowy and Kentish Plovers (Oberholser 1922), the extensiveness and vibrancy of the rufous-orange crown and thickness of the black eyeline on alternate plumaged male Kentish Plovers can separate them. Adult male Snowy Plovers can show a rufous-orange wash to the crown at the beginning of the breeding season (e.g., ML226918741, ML221007011, ML92937001, ML52080491, ML247521021, ML432962191) but it is never as vibrant and extensive as breeding male Kentish Plovers or the Shemya plover. Adult male Snowy Plovers can show an eyeline/partial eyeline (e.g., ML451368811, ML221007061), but it is never as uniform, straight, and completely black as on adult male Kentish Plovers or the Shemya plover. Both of these features (crown and lores color) on the Shemya plover are consistent with Kentish Plover and outside the extremes of the Snowy Plover. The wind conditions leading up to the sighting were favorable for Asiatic vagrants. Beginning on May 26, SW winds from Northern Honshu and Hokkaido, Japan began blowing NE through the Kuril Islands and to the east of the Kamchatka Peninsula. These SW winds continued for 24 hours through May 27 off the eastern shore of the Kamchatka Peninsula. Shemya Island continued to experience SW winds through May 28, but winds shifted to S just south of the Kamchatka Peninsula. Winds shifted to the SE on Shemya and the Kamchatka Peninsula on May 29; the day the plover was discovered on Shemya. The Shemya plover’s plumage characteristics all point towards its identity of an adult male Kentish Plover (Charadrius alexandrinus nihonensis). The extensive and vibrant rufous-orange cap and thick black eyeline are not seen in any of the similar looking Charadrius plovers. While Oberholser (1922) believed there was too much overlap in plumage characteristics (rufous-orange crown and dark lores) to separate Kentish and Snowy Plovers, the Shemya plover is an extreme example that shows characteristics inconsistent with any Snowy Plover. The vocalizations are also consistent with Kentish Plover. Its location in the Western Aleutians and the prevalent SW winds leading up to the discovery also support a bird of Asian origin.

Technical information

Dimensions

2204 pixels x 1322 pixels

Original file size

1.48 MB