Nesting Habits of the Mud Turtle

Abstract

THERE is no record of late summer nesting of the mud turtle Kinosternon subrubrum subrubrum (Lacepede). There are few published records of late nesting of any of the turtles and none of these suggest that there might be a period of late summer nesting normal for the species observed. Observations from 1940 to 1944 at Shackelford Farms, near Lanexa, in New Kent County, Virginia, disclose that in this locality Kinosternon normally has a late summer nesting period in addition to the nesting period in early spring. Kinosternon is abundant here as are the associated forms, Sternotherus o. odoratus, Chelydra s. serpentina, Pseudemys r. rubriventris, and Chrysemys p. picta. Of these, Kinosternon, Chrysemys, and Pseudemys have similar preferences in nesting sites. The same plot of ground serves as a common nesting area for these three turtles and also for one snake (Abastor). The largest number of nests were found in sand roads and in the edges of sandy fields in the vicinity of marshes and on the points of high ground which extend out into the marshes. Since the soil of the lower coastal plain terrace in this locality (Pamlico) is sandy, most of the nests seen were in sandy soil. That soil texture is not a limiting factor is indicated by the presence of nests in the clay banks of an artificial pond. Good drainage and exposure to the sun are of more importance as favorable factors, and appear to be the primary requisites for nest sites. While nests have been observed in thickets and in open woods, they have not been found in situations as shaded as that in which both Chelydra and Sternotherus have been observed laying. Most of my observations were made in one nesting area, a zone approximately 25 feet wide and 1700 feet long, around two sides of a sandy field, adjacent to a large marsh. This nesting area was under observation from 1940 to 1944. It was observed regularly every two days in September, 1942, when late summer nesting was first noticed. During the summer of 1944 it was examined after every rain, when new nests were distinguishable by the freshly disturbed soil. The number of newly constructed nests and the dates when they were found are shown in Table I. Most of these nests had been opened by predators, but occasionally an undisturbed nest was recognized by the appearance of the soil; additional nests were exposed by plowing. Nesting starts the last week in March and was observed in April and June. Observations are lacking for May. In 1944 there was an unusually long period of hot, dry weather with no rain from April 23 until June 30. On June 30 there was a steady rain lasting all afternoon and continuing until about midnight. The following day (July 1) thirty-four nests were found that had been opened during the night by skunks. The appearance of the shells indicated that these eggs had been laid the night before or the previous day. In addition to these, two undisturbed nests were found, both of which had been made after the rain. During July, 1944, there were frequent showers but new nests were seen only once, on July 14, when nine were discovered. All had been opened by skunks except one that had just been completed and