Reptile populations were sampled in spring and summer in various habitats: grassland, creosote shrubland, pinyon-juniper woodland, cottonwood forest, subalpine forest, and subalpine meadow. On 18 sites mark-release methods were used; on 12 sites, all animals were kept for museum specimens. Museum specimen preparations included skulls, whole skeletons, and alcohol preservations; all specimens had tissue samples (liver, heart) taken for ultra-cold preservations for genetic analyses; some were karyotyped. All museum specimens were checked for internal parasites.
Livetrapping of lizards and snakes on the Sevilleta was done by using pitfall traps connected with drift fences. A pitfall trap consisted of two large ( 10) cans connected end to end resulting in a trap approximately 44 cm deep and 15 cm in diameter. The traps were inserted into the ground so the tops are flush. Two pitfalls were placed into the ground approximately 6 meters apart and connected with a 12 cm tall aluminum flashing fence. The fence guided the reptiles into the pitfall traps.
There were 24 pitfall traps per web (12 sets) totaling 120 per site. Seventy-two of these were for mark and recapture studies, while the remaining 48 werefor the collection of museum specimens.
The pitfalls were covered with aluminum flashing lids that sit approximately 2.5 cm off the ground. The lids provided complete shade and protection from precipitation. The trap floors were also punctured to permit drainage if necessary.
The pitfall traps were opened for three weeks at a time, and were checked every two or three days by a crew of two to five. At the end of the three weeks they were closed by covering the openings with a square ceramic tile, 20 cm per side. The edges of the tiles were then covered with dirt as an extra safeguard against penetration. All pitfalls were checked for the presence of animals by removing the aluminum lids and visually inspecting each trap's interior. Lizards found in the traps on the collection webs were removed from the traps, placed in plastic bags with an adequate supply of air, and transported to the lab for processing. Lizards found in pitfalls on mark-recapture webs were removed by hand, then identified to species level, checked for previous capture and individual identification marks, measured, weighed and sexed. The lizards were toe-clipped with no more than two toes cut per foot, and the longest toes on the hind feet left intact.
All snakes were identified to species level, and non-venomous snakes were measured and weighed but not marked because so few are captured. Venomous snakes were removed from pitfalls by the head animal technician using a "snake stick" which enabled the user to handle snakes safely without injury to the snake.
All lizards and snakes are released at the exact location of capture.
This data set was obtained from the Mac computer of Howard Snell, Asst. Professor at UNM. All data from years 1989 and 1990, were entered by him or his assistants. As 1989 and 1990 data sets were in separate files, they have been merged together as one file in this data set. The format was changed to "rdb" format in order to allow the data set to be used on the Sevilleta system. File begin edit: May 28, Michelle L. Murillo: changing to rdb format.File end edit: May 28, Michelle L. Murillo.
Note: holder, measurer, recorder taken out, can be found on original data sheets.