1552 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 3 



The birds also eat the almost unbelievably enormous numbers of 

 seeds of salicornia released when the spikes wither in winter. The 

 birds probably take these seeds whenever they find them, but their 

 consumption is especially noticeable after the high winter tides when 

 the loose seeds have gathered in great, floating windrows up to a foot 

 thick and form a concentrated food source. Song sparrows spend 

 almost all the morning hours foraging, mostly on the masses of sali- 

 cornia seeds; they also eat invertebrate animals they find within the 

 seed masses. 



Reactions to high tides.' — It is possible to mention only the diurnal 

 behavior evident during the daytime high tides in December; pre- 

 sumably equally important behavior patterns occur when breeding 

 adults and young contend with the night high tides in spring, but 

 they have not been witnessed. It is known that nestling song sparrows 

 about 8 days old escape flooding by climbing up into vegetation 

 above their nests. 



The tallest salt marsh vegetation is leafless in December. When 

 tide water rises within a foot to a few inches from the tops of these 

 plants, little cover remains for song sparrows. When no potential 

 avian predators are in evidence, the sparrows usually maintain an 

 active, vigorous foraging pattern. Occasional birds splash in the 

 water in typical bathing routines, and others loaf. A few birds 

 apparently wander beyond their autumnal territories, and occasional 

 examples of territorial strife are evident. Such occurrences end in a 

 chase, and the intruder moves back to his presumed point of origin. 

 One banded bird was seen under such circumstances to have moved 

 about 150 yards, and thus made a round trip of 300 yards. 



I reviewed the influence of winter high tides on two distinct popula- 

 tions of salt marsh song sparrows before completing my observations on 

 the behavior of M. m. samuelis. In a marsh where extensive, man- 

 made levees existed, the song sparrows accumulated on them, but 

 on a marsh where only emergent vegetation and floating timbers were 

 available, no such concentrations were seen. Later observations on 

 this marsh from a 6- by 30-foot raft floating at high tide showed that 

 the song sparrows there did indeed congregate; at one time immedi- 

 ately after a marsh hawk passed, 17 song sparrows were perched on the 

 raft. The birds apparently felt exposed in the thin emergent vege- 

 tation, and those from as far as 60 yards away streaked toward the 

 raft in full, powered flight. After the hawk passed the birds gradually 

 left the raft, but each time a hawk approached they returned to it. At 

 the same time, the foraging or loafing song sparrows practically ig- 

 nored short-eared owls; this difference in reaction to the raptors lends 

 support to the idea that short-eared owls are unimportant predators 

 on song sparrows. 



