690 tr.S. NATIONAL MUSEUM BULLETIN 237 part 2 



its use by predators are relatively few; the observations that follow 

 afford us only token insight into this important control on the species' 

 numbers. 



Owls. Richard M. Bond (1939) found them frequently used as 

 food by either horned owls or barn owls. Evans and Emlen (1947) 

 state more definitely that the Savannah sparrow was the only common 

 wintering bird in Davis, Calif., that was represented in appreciable 

 numbers in barn owl pellets. Errington (1932) records Savannah 

 sparrows as prey of the long-eared owl in southern Wisconsin. J. A. 

 Munro (1929) reported two Savannahs killed by short-eared owls at 

 Beaver Lake, Alberta, Canada. 



Hawks. J. GrinneU (1923b) watched a sharp-shinned hawk 

 pursue and successfully capture a Savannah sparrow, which later 

 proved to be anthinus. W. J. Breckenridge (1935) includes Sa- 

 vannahs as part of the diet of the marsh hawk in Minnesota, and 

 E. W. Martin (1939) lists them among prey of the pigeon hawk. I 

 have several times seen a sparrow hawk slip off a telephone pole, fly 

 fast and low over the grass tops, and make an unsuccessful grab at 

 a feeding Savannah sparrow. 



While parasites are not enemies in the strictest sense, they do have 

 their effect upon their host. However, in most cases this effect is 

 not measurable. For instance, although the brown-headed cowbird 

 victimizes the Savannah sparrow rather infrequently (Friedmann, 

 1963) each parasitized nest means a loss of potential parent replace- 

 ment, and how this affects the aggregate population has never been 

 assessed accurately. Similarly the effect of body parasites upon the 

 Savannah sparrow has not been determined. 



R. O. Malcomson (1960) reports the presence of the bird louse 

 Ricinus diffusus (MaUophaga) on Savannah sparrows. 



Carlton M. Herman (1937) reports Savannah sparrows as hosts 

 to the Hippoboscid louse flies Ornithomyia fringillina, which Bequaert 

 also identified in a sample collected from Savannahs in Rhode Island. 



Herman (1944) lists the following blood protozoans from the 

 Savannah sparrow: Trypanosomidae {Trypanosoma sp?), Plasmodi- 

 idae (Plasmodium sp?), Haemogregarinidae (Toxoplasma sp?). 



Fall. — For the period between the close of the nesting season and the 

 onset of migration, Forbush (1929) reports that in Massachusetts "The 

 birds gather in family groups and roam the fields and meadows." 

 Palmer (1949), speaking of Maine birds, says that "In August, after 

 nesting is ended, hundreds of the birds often are found in a small area 

 of salt marsh. These are mostly young of the year, that linger in 

 these areas of adequate food and shelter before flying south." 



While we may not know exactly where the birds spend the post- 

 breeding period, it seems reasonably certain that little, if any, long 



