Bobcat Lynx rufus Home Range, Density and Habitat Preference in South-Central Arizona

Abstract

-Home range size, density, and habitat preference was estimated for a bobcat population on a portion of the Three Bar Wildlife Area, Arizona. Five adult females and two adult males were radio-located 394 times between September 1976 and January 1978. Female and male home ranges averaged 4.8 km2 and 9.1 km2, respectively. Home range size varied little within each sex. Female bobcat home ranges tended to be relatively exclusive with respect to other females. The arrangement of male home ranges was less exclusive, and male and female home ranges overlapped extensively. Estimated minimum density of adult resident bobcats was one bobcat per 3.9 km2. Bobcats preferred riparian habitat. The bobcat (Lynx rufus baileyi) has been little studied in the southwest deserts of the United States. Jones and Smith (1979) studied the bobcat's diet in Arizona, but little information was gathered on home range or habitat preference. The majority of bobcat research has focused on diet and reproduction. With the development of radio-telemetry, more accurate data have been collected on bobcat home range and movements (Marshall and Jenkins, 1966; Bailey, 1972; Lembeck, 1978). The home range and habitat preference of bobcats have not previously been studied in a Sonoran desert environment. This study was conducted from July 1976 to January 1978 to ascertain: (1) home range size; (2) spatial distribution of home ranges; (3) population density; and (4) habitat preference, of a bobcat population in a Sonoran desert environment in central Arizona. STUDY AREA.-This study was conducted on the Three Bar Wildlife Area, in central Arizona in the Tonto National Forest, just west of Lake Roosevelt. Rainfall the past 20 years averaged 36.4 cm per year, and temperature extremes range from 43°C during the summer to -7°C in the winter. Steep slopes and rocky ravines are the main topographic characteristics of the Three Bar. This area has been ungrazed since 1947, and hunting and trapping of predators was banned in 1972 (Jones, 1977). The study area was on the northeast portion of the Three Bar. The elevation varies between 600 m and 1500 m. The study area supports four major habitats: Sonoran desert scrub, desert grassland, chaparral, and riparian (Dickerman, 1954). METHODS.-Using No. 2 steel leg-hold traps, five female and three male bobcats were captured. One male died from trap injuries. Trapping was done in a 6 km2 area in an attempt to capture all individuals. Trapped bobcats were immobilized with ketamine hydrochloride (16.5 mg/kg of body weight) and fitted with collar-mounted radio-transmitters (Telonics Inc., Mesa, Arizona). Instrumented bobcats were located primarily by triangulation from the ground, using a directional antenna. Whenever possible three or more azimuth readings were taken. An attempt was made to locate bobcats daily. The day was divided into 6 sampling periods which were cued to sunrise and sunset. Dawn was classified as beginning one hour before sunrise and ending one hour afterward. Dusk was, in like manner, a two hour time block set around sundown. The other 4 time blocks were classified as follows: 1) morning, between dawn and noon; 2) afternoon, between noon and dusk; 3) evening, between dusk and midnight; and 4) early morning, between This content downloaded from 207.46.13.112 on Mon, 03 Oct 2016 05:01:13 UTC All use subject to http://about.jstor.org/terms The Southwestern Naturalist BOBCAT 1 BOBCAT 3 ..... BOBCAT 4 ---BOBCAT 5 BOBCAT 6 BOBCAT 7