None of the above workers, however, obtained very much information on comparative numbers of species.

Tables [8], [9], and [10] present the writer's findings on populations of migratory shore birds in Micronesia in 1945. At Guam, as shown in [table 8], the records for March, April and early May are few, owing to a limited amount of field observation. Beginning in late May and until October 24 a greater amount of time was spent in the field and more regular records were obtained. No observations were made by the author at Guam in the period from August 11 to September 25. The dates marked with an asterisk are those on which observations were made on the extensive tidal flats at Agfayan Bay and vicinity. These flats, at low tide, present excellent feeding grounds for waders and in 1945 were undisturbed by parties of service personnel, because the area was "off-limits."

[Table 8] shows that Pluvialis dominica, Numenius phaeopus, and Heteroscelus spp. were the shore birds most frequently found at Guam in this period. Pluvialis dominica was the most numerous of the three species. Of Heteroscelus there was approximately equal representation of H. incanus and H. brevipes as indicated by specimens collected. These birds were not identified to species in the field.

Although records were made only infrequently in the spring migration, such information as was obtained indicates that the populations were largest in March and early April. On April 24, Pluvialis dominica was the only bird observed on beaches and in upland openings. On April 26, a single Limosa lapponica was recorded. On May 15, no shore bird was seen on a trip along several beaches. In late May and early June, single individuals of Heteroscelus were found. Of this genus, those collected in May were in nuptial plumage, and those collected in June were in winter plumage and probably should be classed as non-migrants. Numenius phaeopus was occasionally recorded beginning in early June, but waders were totally absent from beaches at Agfayan Bay and vicinity on June 18 and 19. Few shore birds were seen in early August. In late September, birds, especially Pluvialis dominica, Numenius phaeopus, and Heteroscelus spp., were numerous. These species were numerous until October 24, when observations were discontinued.

Of the 17 species of migratory shore birds recorded from the Mariana Islands, eight were identified. Of these eight, three species, Limosa lapponica, Actitis hypoleucos, and Charadrius mongolus, were found on only one occasion. Never more than four species were identified on a single field trip. These data give an idea of the lack of variety of species that may be observed on Micronesian islands.

Table 9. Populations of Migratory Shore Birds Seen at Ulithi Atoll in 1945

Table 9. Populations of Migratory Shore Birds Seen at Ulithi Atoll in 1945

SpeciesIsland and Date
PotangerasFas-
sari		Mange-
jang		PauLosiep
Aug.
14		Aug.
15		Aug.
16		Aug.
17		Aug.
19		Aug.
20		Aug.
21		Aug.
22
Pluvialis dominica 6 5 4 10 5
Charadrius mongolus x 2
Numenius phaeopus1 4 1 1 2
Actitus hypoleucos 2 2
Heteroscelus spp. 2 6 3
H. incanus* 1 2
Crocethia alba 30 5
Total No. of Individuals1 4 6 6 6 1 49 21
Total No. of Species1 1 1 2 2 1 6 6

* Figures based on identified skins.

x Observed but numbers not recorded.