A demographic study of the ringneck snake (Diadophis punctatus) in Kansas

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Field records of more than 14,000 individuals of Diadophis punctatus were assembled over a 26-year period on several small study areas, mostly within a 0.5-mile radius, at the University of Kansas Natural History Reservation, with emphasis on marking and recapture. Emergence from hibernation begins in late March and continues into early April, ovulation occurs in the latter half of May, and the elongate, sausage-shaped eggs, averaging approximately 3.9 per clutch, are laid in late June or early July. Hatching occurs at the end of August or in September. Females become sexually mature after their third hibernation, typically at a snout-vent (S-V) length of approximately 235 mm, but males mature a year earlier, at a minimum S-V length of 166 mm. Growth continues, but at a reduced rate, after attainment of sexual maturity. Snakes already above average adult size typically gain from 1–3% in length annually. Mortality of adults is not age-specific, and loss is approximately 25% annually. A small percentage of the snakes survives to an age of 15 or more years. Young seem more secretive than adults and are less well represented in samples. Sex-ratio in samples is subject to drastic seasonal fluctuation; females range from 24% in early fall to 71% in midsummer, but in late March, April, and early May, when the snakes are most in evidence, males are always more numerous. The snakes are active over a wide range of temperatures but tend to maintain body temperatures between 25 and 29.5 ˚C. Their surface activity is chiefly at air temperature within or below this range, and at higher air temperatures they retreat underground. Body temperature is maintained by contact with sun-warmed objects that the snakes use for shelter. Occasionally, at relatively low air temperatures, the snakes venture into the open and bask in sunshine. Earthworms, especially Allobophora caliginosa, provide most of the food, and it is estimated that each snake consumes on average approximately 3 x its body weight in earthworms annually. Seven calculations of population density (based upon recapture ratios) varied from 719 to 1849/ha and averaged 1266. Eight kinds of predators on the Reservation were found to eat ringneck snakes, but their toll would account for only part of population regulation. The copperhead, racer, and red-tailed hawk were the predators in most recorded instances, but moles, mice, and birds other than raptors may also be among the important predators. Marked snakes were recaptured at distances of zero to 520 m from the original capture site; however, one-fourth were within 10 m, even after intervals of several years, showing a strong tendency to remain within a home area. Home ranges were often elongate, with maximum axes of approximately 140 m. Ranges tend to be progressively altered through time.

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ELECTRONIC FILE - Zoology