DODD & FRANZ: UPLAND SNAKES


during this study although in other areas they are common in wetlands (e.g.
Hudnall 1979).
 The rest of the snakes trapped during the study were caught infrequently.
Based on other observations (see below), several of them (e.g. Crotalus
adamanteus, Pituophis melanoleucus) are known to be common on the Ordway
Preserve (Timmerman 1989; CKD and RF unpubl. data). Others are wetland-
associated species. Only Heterodon platyrhinos appears to be rare on the Ordway
Preserve and was trapped infrequently. Additional sampling, using a variety of
techniques in more habitat types, will be necessary before the habitat associations
of these species on the Ordway Preserve can be discerned.
 We suggest that a possible explanation of the similarity of the upland snake
faunas in different habitat types on the Ordway Preserve is that they share a similar
derivation. Approximately 47 percent of the uplands presently are in high pine
vegetation. Xeric hammocks are found surrounding the numerous lakes in formerly
cultivated areas on the property and in the Mill Creek valley. Examination of aerial
photographs taken more than 30 years ago and conversations with elderly residents
familiar with the land confirm that most xeric hammocks were cleared for
agriculture or homesteads at one time, usually 50 to 70 years ago. These hammocks
probably were in high pine vegetation prior to cultivation. Thus, the xeric
hammocks are of relatively recent origin and do not contain species, such as
Storeria occipitomaculata, found in historically undisturbed hammocks.

 Seasonal Activity Patterns.- The five most commonly trapped species did
not show similar seasonal activity patterns, and the activity patterns (Fig. 4) often
were different from literature records. For example, Coluber constrictor is reported
to have a bimodal seasonal activity period in Nebraska, based on road kills (Oliver
1955), and a unimodal activity period centered on the late spring to early summer
in South Carolina (Gibbons and Semlitsch 1987) and southern Florida (Dalrymple
et al. 1991b). Micrurus is active year-round in Florida with a bimodal activity
season in spring and autumn (Jackson and Franz 1981; Dalrymple et al. 1991b).
Our observations are similar to literature records for Sistrurus (Hudnall 1979;
Dalrymple et al. 1991b), Masticophis (Ford et al. 1991), and Cemophora (Reynolds
1980; Gibbons and Semlitsch 1987; Dalrymple et al. 1991b).
 The four most trapped species were active throughout the sampling period, as
reflected in niche breadth values. Micrurus overlapped seasonally least with the
other species, whereas the warm weather xeric habitat species Cemophora,
Masticophis, and Sistrurus had the greatest seasonal niche overlap. The spring
activity peak in Coluber and the autumn increase in Sistrurus are reflected in their
medial niche overlap values. In general, there does not appear to be much seasonal
partitioning of activity, perhaps because of the generally long activity seasons of
most species.
 Gibbons and Semlitsch (1987) suggested that Temperate Zone snakes showed
two general activity patterns, a unimodal pattern centered on warm weather