The flocks of plover seen by the NAMRU2 party varied in size from three to 30 birds, the average being less than ten. Coultas (field notes) noted "large flocks" at the Palaus from October to December, 1931. Although plover was often found on the same beach as other birds, the NAMRU2 observers rarely saw plover together with other shore birds. However, on air strips Pluvialis occasionally occurred with small numbers of Arenaria, Heteroscelus spp., and Numenius phaeopus. Pluvialis and N. phaeopus were the only shore birds found to use open grassy flats and other inland areas at Guam and Peleliu in 1945.
Stickney (1943) records Pluvialis in late spring and summer from Polynesia, indicating these to be birds remaining in the winter range during the breeding season. The NAMRU2 party observed no Pacific Golden Plovers at Guam which might be regarded as non-migrants, but other species of shore birds were found which might be considered as such. The lingering of individuals in the winter range is not unusual among migratory birds, and as Stickney points out, most of the non-migrants retain their winter dress or assume an incomplete breeding plumage.
Charadrius hiaticula semipalmatus Bonaparte
Semipalmated Plover
Charadrius semipalmatus Bonaparte, Journ. Acad. Nat. Sci. Phila., 5, 1825, p. 98. New name for Tringa hiaticula Ord. not Charadrius hiaticula Linnaeus, in Wilson's Amer. Ornith., Ord. repr., 7, 1824, p. 65. (Type locality, Coast of New Jersey.)
Charadrius hiaticula Finsch, Ibis, 1880, p. 331 (Taluit); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 64 (Taluit or Bonham); Schnee, Zool. Jahrbücher, 20, 1904, p. 389 (Marschall-Inseln); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 45 (Taluit).
Geographic range.—Breeds from Arctic America south to coastal Canada. Winters from southern United States to South America. In Micronesia: Marshall Islands—Jaluit.
Remarks.—Finsch (1880d:331) reported this bird (sight record) at Jaluit in the Marshall Islands. Other than this observation, there is no history of the species in Micronesia.