Thesis Title

Habitat Choice and Spatial Ecology of Nerodia Sipedon, the Northern Water Snake

Date of Graduation

Summer 1999


Master of Science in Biology



Committee Chair

Brian Greene

Subject Categories



This study utilized radio telemetry to examine the spatial ecology and habitat choice of Nerodia sipedon in a lentic ecosystem in southwestern Missouri. In late spring of 1998, radio transmitters were implanted into 18 adults, which were located daily. Home range areas and shifts in activity centers were calculated using several different estimation techniques. Additionally, structural and climatic variables were measured at 358 individual snake locations and compared to the same measurements at 161 random sites to evaluate habitat selection. The estimation technique has a large effect on home range area. Female Nerodia sipedon tend to occupy larger areas than males, although there is a large amount of variation within and between the sexes. There is a positive relationship between body condition and home range area in females that may be associated with reproductive constraints. Activity areas of males were not affected by condition. Both sexes underwent shifts in activity centers throughout the season with little variation in seasonal movement between sexes. Habitat use of N. sipedon was non-random as determined by comparison of snake-selected sites with available habitat. Snakes utilized littoral aquatic habitat almost exclusively during the summer. However, sexual differences in habitat use were apparent with females preferring open off-shore areas with dense emergent vegetation, and males utilizing more shaded shoreline areas. These differences were likely driven by specific thermal requirements of gravid females.


© Timothy C Roth