The racer dwells primarily in open situations, but as might be
expected from its extensive geographic range, bringing it under the
influence of diverse climates and habitats, its populations have
diverged somewhat in adaptation to different environmental conditions.
The eastern blacksnakes (subspecies _constrictor_ and _priapus_) seem
to prefer woodland and forest edge. In central Louisiana, _anthicus_
occurs chiefly in an open type of woodland. The subspecies
_stejnegerianus_ is found chiefly in brushland and thorn forest. The
western _mormon_ is found in varied habitats, including moist
streamside meadows, and chaparral. Published statements of
herpetologists, based upon studies in limited areas, are briefly
quoted below to show the trend of geographic change.
_C. c. constrictor_: This snake "occurs chiefly in fields" (Atkinson,
1901:148; Pennsylvania); "in more or less wooded regions and along
hillsides and among bushes" (Surface, 1906:167, in Pennsylvania);
"abundant, especially in wooded regions" (Hibbard, 1936:28, in
Kentucky); "dry and more or less open places" (Conant, 1938:52, in
Ohio); "old fields and areas about buildings" (King, 1939:572, in
Tennessee).
_C. c. priapus_: In "drier parts of the [Okefinokee] swamp ... seems
to prefer blueberries and saw palmettos" (Wright and Bishop, 1915:159
in Georgia); "common in grassy fields and in upland woods" (Allen,
1932:13, in Mississippi); "abundant along fence rows ... in dry
pine-oak forest and in bottomland forest" (Trowbridge, 1937:296, in
Oklahoma); "probably most abundant in open upland hammock or in old
fields; limestone flatwoods" (Carr, 1950:80, in Florida); Oak and
oak-hickory forest and small hill prairies in southern Illinois
(Rossman, 1960:219).
_C. c. paludicola_: In "all parts of the freshwater Everglades, in
cabbage palm hammocks, in salt marshes, and in mangrove swamps. On Key
Largo ... in mesophytic hammock" (Duellman and Schwartz, 1958:296, in
southern Florida).
_C. c. anthicus_: In "wooded areas in the vicinity of briar patches or
other brushy undergrowth" (Clark, 1949:249, in northern Louisiana);
"especially grassy uplands" (Fitch, 1949:88, in central Louisiana).
_C. c. stejnegerianus_: Of 291, 94 were in scattered brush, 92 in
sparse brush, 41 in lightly wooded areas, 26 in grassy areas, 24 in
heavy brush, eight in semi-arid places and six in heavily wooded
situations (Auffenberg, 1949:55, in southern Texas).
_C. c. mormon_: In "thin brush skirting open prairie land" (Lord,
1866:304, British Columbia); cottonwood-willow and water margin
habitats in prairie (Dice, 1916:310-312, in eastern Washington);
"grass; amid water cress; bank of small ditch near meadow; barley
field; sandy ground covered with rocks and driftwood; among sedges; in
sagebrush; swimming in irrigation ditch" (Grinnell, Dixon and
Linsdale, 1930:149, in northeastern California); low foothills, around
the fields, and in the timber and brush along the canyon bottoms
(Woodbury, 1931:75, in Utah); "open woods of Garry oak and poison oak,
on grassy slopes, in chaparral, and in grain or hay fields" (Fitch,
1936:644, in southwestern Oregon); "low hot canyons where it was found
to occupy areas having rather dry, rocky hills" (Ferguson, 1952:68, in
northeastern Oregon).
_C. c. flaviventris_: Pastures, meadows, and fields (Hurter, 1911:170,
in Missouri); "usually frequents dry open fields, although it is often
found in bushes or cut-over land which has grown up into thickets"
(Ortenburger, 1928:181); "pasture lands and on hill sides" (Peters,
1942:183, in Illinois); "along the levees in the salt marshes" (Liner,
1954:82, in southern Louisiana); "common in both prairie and woodland
habitat" (Smith, 1947:34, in east-central Illinois); Flood plain, sand
around sage-sumac brush, rocky slopes (Fouquette and Lindsay,
1955:411, in northwestern Texas).
Several observers have described the habitat in Kansas as follows:
"grassy valleys and thinly wooded hillsides" (Burt, 1927:5); "moist
and dry habitats, in wooded areas, and in prairies" (Smith, 1956:237);
Oak-walnut hillside forest, cultivated field, buckbrush-sumac, prairie
(Clarke, 1958:22).
Every part of the 590-acre Reservation is used to some extent by blue
racers living on this area. Home ranges of most individuals are so
large as to include a variety of habitats, both woodland and
grassland. The habitat preferences vary according to season. In autumn
some racers migrating to rock ledges to hibernate are found in mesic
forest, but at that time of year leaves have begun to fall and the
forest floor is less dark and humid than in summer. In spring also
racers not yet back on their summer ranges are often seen either along
the hilltop ledges, or moving downhill through woods toward bottomland
meadows. However, in summer, the finding of a racer in mesic woodland
is a rare event. Occasionally the snakes make trips across such blocks
of woodland hundreds of feet wide, but they do not linger in the
woodland. In decreasing order of preference the habitats used by
racers on my study area may be classified as follows:
1. Tall-grass prairie, (Plate 22) either original or regenerated,
dominated by native perennial grasses in stands three feet to seven
feet high, including big blue-stem (_Andropogon gerardi_), little
blue-stem (_A. scoparius_) Indian grass (_Sorghastrum nutans_), and
switchgrass (_Panicum virgatum_).
2. Pastureland, with introduced brome grass (_Bromus inermis_) and
associated weedy vegetation.