Coyote (Canis Latrans) Food Habits in a Tropical Deciduous Forest of Western Mexico

Article excerpt

ABSTRACT.-We studied the food habits of the coyote (Canis latrans) in a tropical deciduous forest along the Mexican Pacific coast during 1996 and 1997. Small mammals, chiefly the Jaliscan cotton rat (Sigmodon mascotensis), were the main prey items during the dry season. Cultivated fruits, like mango and papaya, were the most important food for coyotes during the wet season. Given the importance in our study area of human related food items like the Jaliscan cotton rat, mango and papaya, we expect the expansion of coyote populations due to deforestation of the tropical deciduous forest.

INTRODUCTION

Coyotes are one of the most studied carnivores in North America, with considerable research done on their feeding habits (Bekoff, 1977); however, information about coyote in the southern area of its range (Mexico and Central America) is rather limited (Hernandez and Delibes, 1994). Studies on coyote food habits south of the United States have been conducted mainly in temperate areas such as pine forest, pine-oak forests and grasslands (Vaughan and Rodriguez, 1986; Salas, 1987; Delibes et al., 1989; Servin and Huxley, 1991; Aranda et al., 1995; List, 1997) or in subtropical areas such as deserts and shrublands (Arnaud, 1981; Hernandez and Delibes, 1994; Hernandez et al., 1994; Sanabria et al., 1996). Only one study has been carried out in forested areas of the tropics (Vaughan and Rodriguez, 1986).

Based on a north-south trend of reduction in coyotes home range, Gompper and Gittleman (1991) hypothesized that coyotes in southern latitudes should be more frugivorous than carnivorous because of the higher availability of fruits and higher primary productivity in those habitats. In a similar way, Voight and Berg (1987) speculated that a north-south trend exists in the food habits of coyotes due to an increased availability of small prey in southern latitudes. Under these assumptions, we expect that in tropical areas coyotes should feed mainly on small prey and fruit. However, the only food-habits study done before in tropical areas (Vaughan and Rodriguez, 1986) showed that coyotes fed mainly on wild ungulates, taking small prey and vegetables as secondary items. These contradictory findings show that generalizations about coyote diet should be made cautiously.

The limited knowledge of coyote ecology in many tropical areas has not been perceived as a problem in the past, but should be considered critical for the production of effective management plans. Coyotes may have a great impact on the composition and structure of local mammal communities (Henke and Bryant, 1999). This point is particulary important in ecosystems considered endangered, like the tropical dry forest (Janzen, 1988), where coyotes are likely to increase with deforestation and other human activities (Vaughan, 1983; Sosa-Escalante et al., 1997). The objective of our study was to describe the food habits of the coyote in a tropical deciduous forest of the western coast of Mexico.

METHODS

Study area.-The study area was located in the Chamela-Cuixmala Biosphere Reserve (CH-CBR) (19 deg 30' to 19 deg 33'N and 105 deg 00' to 105 deg 04'W) on the southwestern coast of the Mexican state of Jalisco. Climate in the region is warm subhumid with an average temperature of 18 C in the coldest month and 24 C in the warmest. Annual average precipitation is approximately 750 mm concentrated in a relatively short wet season (July to October). Elevation varies from 0 to 500 m above sea level (Bullock, 1988). The main vegetation type is tropical deciduous forest, located mainly in upland regions (Rzedowsky, 1983). The most abundant tree species are: Cordia ellidora, Caesalpina meriostachys, Lonchocorpus spp., Jathropha chamelensis, Guapira sp. and Croton sp. (Lott, 1985; Bullock, 1988). Tropical deciduous forest is considered the most endangered tropical ecosystem in the world (Janzen, 1988). The second most widespread vegetation type in the area is the tropical semideciduous forest, located in valleys and riparian areas. …