870 U.S. NATIONAL MUSEUM BULLETIN 237 part 2 



extended into the woods, the average territory may be somewhat 

 larger than the estimate just given. We have frequently seen the 

 vesper sparrow in territorial combats essentially similar to those 

 described by M. M. Nice (1937: 57-58; 1943: 153-156) for the Song 

 Sparrow." John L. George (MS.) found 9.9, 8.7, and 9.5 pairs of 

 vesper sparrows per 100 acres of cultivated farm land during a 

 3-year study in southern Michigan. 



It seems likely that the number of pairs inhabiting extensive 

 cultivated tracts planted to hay, wheat, or corn is limited by the 

 number of available song perches rather than by actual territorial 

 conflict. The vesper sparrow rarely sings on the ground, and it 

 seems to prefer the highest singing perches available. Favorite song 

 perches in nesting areas bordered by woods are branches 25 or more 

 feet above ground along the woods' edge. Where there are no trees, 

 the song perch may be a fence, a dead weed, a thistle, shrub, or any 

 vegetation or structure higher than the nesting substrate. 



G. M. Sutton (MS.) notes: "In areas inhabited by both vesper and 

 grasshopper sparrows I have never witnessed interspecific territorial 

 disputes of any sort. I think it quite possible that nest-territories 

 of these two species may occasionally overlap. As for the vesper 

 and lark sparrows, I have never seen one species chasing, or fighting 

 with, the other." 



Rarely I have observed a vesper sparrow chase a song sparrow or 

 a field sparrow, but usually these species nest and feed together with- 

 out conflict. On May 10, 1946 I found a vesper sparrow nest 14 

 yards from a killdeer {Charadrius vociferus) nest and 21 yards from 

 a field sparrow nest. Ralph A. O'Reilly, Jr., found a nest July 3^ 

 1950 only 10 feet from a killdeer nest. 



Courtship. — According to E. H. Forbush (1929), "courtship is 

 carried on mostly on the ground. The male walks or runs before or 

 after the female, %\dth wings raised, and both wdngs and tail widely 

 spread, occasionally rising into the air to give his flight-song." How- 

 ever, the vesper sparrow rarely gives a true flight song. 



Nesting. — As far as is known the vesper sparrow invariably places 

 its nest on the ground, frequently near small patches of bare ground 

 or where the vegetation is sparse and low. First nests — those built 

 in April or early May— may be built in an excavation in the ground 

 under cover of prostrate dead weed stems; these nests may be very 

 well concealed by a complete matted covering of such weeds. Nests 

 along dirt roads or country lanes, or those placed in last year's alfalfa 

 or corn fields, usually are built at the base of a grass tussock, a thistle, 

 a dandelion, some other plant, or even a clod of dirt. Some nests 

 are nearly completely exposed from above during the egg-laying 

 period, but with the rapid growth of spring vegetation, these nests 



