MIGRATION OP PACIFIC PLOVER HENSHAW. 549 



It is probable, however, that day migration is not the rule with 

 plover and other shore birds. Apparently it is more usual for the 

 flocks to feed by day and leave just before nightfall, as do many 

 other birds in different parts of the world. Mr. R. C. L. Perkins 

 states that several times he " witnessed these departures, always late 

 in the afternoon or just before dark." He adds: 



When about to return to the north, the plover frequently assemble in very 

 large flocks, and before setting out on their journey rise to an enormous height 

 in the air, even beyond the range of sight. I have once seen two such flocks 

 start from the same point, the one following the other after an hour's interval. — 

 [Fauna HawaiiensiS, Vol. I, pt. iv, p. 449, 1903.] 



It is interesting to note that plover are occasionally sighted from 

 passing ships. Naturally they attract little attention and never are 

 recorded in the ship's log. I found one ship captain, however, who 

 remembered to have seen a flock of plover passing north in spring. 

 The date was uncertain, but the ship was about midway between San 

 Francisco and Hawaii, and the plover were steering a course which 

 would carry them to the neighborhood of the Aleutians. 



Where data are so scarce and difficult to obtain it is worth noting, 

 as bearing on the season and course of the spring migration of island 

 birds, that Townsend captured a Pacific plover, which boarded the 

 Albatross May 19, 1890, when 600 miles south of Kadiak. This bird 

 was probably an island migrant nearing the end of its long flight. 

 Elliott, also, speaking of the turnstone, stales that he " met with it at 

 sea 700 miles from the nearest land, flying northwest toward the 

 Aleutian Islands, my ship being 800 miles west of the Straits of 

 Fuca." 



Physical condition of spring migrants. — During the last two 

 months of their stay in the islands both the migrating plover and 

 turnstones get very fat, and it is probable that individuals that are 

 not in good condition do not attempt the flight, or if they do, do not 

 survive the attempt. Toward April most plover seem to be in full 

 breeding plumage, and I feel sure that none of the birds assuming 

 the breeding dress remain behind, unless sick or wounded. There is, 

 however, a small contingent, both of plover and turnstones, that sum- 

 mer in the islands, and these appear to consist wholly of immature 

 individuals, which, as a rule, are thin and not in good trim. 



Speed of migrating plover. — The migration of plover over a wide 

 ocean involves two factors: (1) Ability to go without food for the 

 time necessarily consumed in the flight. (2) Ability to make the 

 journey without resting and yet not overtax the physical powers. 

 As stated above, apparently all the migrating birds in spring are in 

 good order, and some of them, especially the males, are exceedingly 

 fat. They are thus in condition to exert their utmost powers for a 

 considerable period and to do without food. I know of no actual 



