Carlos A. López González

ASSESSING EFFECTS OF PREDATION RISK ON FORAGING BEHAVIOR OF MULE DEER

Abstract We applied optimal foraging theory to test effects of habitat and predation risk on foraging behavior of mule deer (Odocoileus hemionus) subject to predation by mountain lions (Puma concolor). We predicted that deer would spend less time foraging, have higher giving-up densities of food (GUDs), and have higher vigilance behavior when occupying patch edges than when in open and forest interiors. We also measured GUDs in 3 microhabitats within 3 forest types. We used pellet-group surveys to estimate habitat and microhabitat use, and we assessed vigilance behavior with automatic camera systems. The GUDs (perceived predation risk) were greater in forests of Douglas fir (Pseudostuga menziensii) than mountain mahogany (Cercocarpus ledifolius). In forests of Douglas fir, GUDs were greatest in the forest interior, declined at the forest edge, and were lowest in the open microhabitat. Microhabitat features did not influence GUDs in the mountain mahogany forest. Pellet-group data indicated more activity in the open than in the edge or forest. Based on photographs, deer were more vigilant at forest edges than in open and forest areas. We concluded that deer are responding to predation risk by biasing their feeding efforts at the scale of habitats and microhabitats and altering their habitat-specific patterns of vigilance behavior.

Ocelot (Leopardus pardalis) Food Habits in a Tropical Deciduous Forest of Jalisco, Mexico

—Few studies have been conducted on the food habits of the ocelot (Leopardus pardalis), considered an endangered feline in Mexico. Past studies showed that rodents were the main component of ocelot diet. In our study ocelot prey consumption was measured as frequency of occurrence of prey in scats and then converted to biomass. The spiny-tailed iguana (Ctenosaura pectinata) was the most important prey of ocelots, followed by the spiny pocket mouse (Liomys pictus). Other rodents and some birds were also present in the scats, although representing only a minor proportion of the ocelot’s diet. Evidence of subadult white-tailed deer (Odocoileus virginianus) was also found in scats indicating that ocelots can either capture prey bigger than themselves or are using deer as carrion.Few studies have been conducted on the food habits of the ocelot (Leopardus pardalis), considered an endangered feline in Mexico. Past studies showed that rodents were the main component of ocelot diet. In our study ocelot prey consumption was measured as frequency of occurrence of prey in scats and then converted to biomass. The spiny-tailed iguana (Ctenosaura pectinata) was the most important prey of ocelots, followed by the spiny pocket mouse (Liomys pictus). Other rodents and some birds were also present in the scats, although representing only a minor proportion of the ocelots diet. Evidence of subadult white-tailed deer (Odocoileus virginianus) was also found in scats indicating that ocelots can either capture prey bigger than themselves or are using deer as carrion.

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

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.

Consensus on criteria for potential areas for wolf reintroduction in Mexico.

Given the conflict with human interests that in many cases results in the extirpation of large carnivores, acceptance of their reintroduction is a considerable challenge. By the 1980s Mexican wolves (Canis lupus) were extinct in the wild. In 1998 a population was reintroduced in the Blue Range Mountains of New Mexico (U.S.A.). Efforts to reintroduce the species in Mexico have been ongoing since the late 1980s. Four teams working independently identified 6 areas in northern Mexico in the historic range of Mexican wolves, where reintroductions could potentially be successful. Each team used different methods and criteria to identify the areas, which makes it difficult to prioritize among these areas. Therefore, members of the different teams worked together to devise criteria for use in identifying priority areas. They identified areas with high, intermediate, and low potential levels of conflict between wolves and humans. Areas with low potential conflict had larger buffers (i.e., distance from human settlement to areas suitable for wolves) around human settlements than high- and intermediate-conflict areas and thus were thought most appropriate for the first reintroduction. High-conflict areas contained habitat associated with wolf presence, but were closer to human activity. The first reintroduction of Mexican wolves to Mexico occurred in October 2011 in one of the identified low-conflict areas. The identification of suitable areas for reintroduction represents a crucial step in the process toward the restoration of large carnivores. Choice of the first reintroduction area can determine whether the reintroduction is successful or fails. A failure may preclude future reintroduction efforts in a region or country.

¿Pueden las variables de paisaje predecir la abundancia de venado cola blanca? El caso del noroeste de México

La generación de información sobre la abundancia de venado cola blanca (Odocoileus virginianus) se ha obtenido a nivel local, lo cual reduce su utilidad para tomar decisiones de manejo y conservación a nivel de paisaje. Nuestro objetivo fue generar un índice predictivo regional para estimar la abundancia de venado cola blanca utilizando imágenes de satélite. La información de campo se generó a partir de estudios locales en dos sitios en el noroeste de México, el primer sitio se ubica en la Sierra de San Luís en el municipio de Agua Prieta, Sonora y el segundo se encuentra ubicado en la Sierra Los Pavos, en el municipio de Sahuaripa, Sonora; de acuerdo a sus características el primer sitio es templado y el segundo es tropical. La densidad de venado cola blanca se calculó por medio de transectos lineales para el conteo de grupos fecales. Se encontró una relación significativa entre el valor de índice de vegetación normalizado (análisis que se deriva de la reflectancia del espectro electromagnétic entre la biomasa verde y su firma espectral; NDVI) y la abundancia de venado cola blanca para una de las localidades muestreada; sin embargo, para la otra localidad no se encontró una relación significativa entre las variables. El NDVI predice la abundancia en el sitio templado y no en el tropical. Al parecer esta relacionado a variables antropogénicas mas que de paisaje. Es posible utilizar el NDVI para identificar áreas de reintroducción para poblaciones de venado cola blanca en sitios templados del Noroeste de México.

Ocelot (Leopardus pardalis): An Addition to the Mammals of Chihuahua, Mexico

Abstract. We present the first documented record of an ocelot (Leopardus pardalis) for the Mexican state of Chihuahua. The animal was camera-trapped in open oak woodland. This finding increases the number of mammal species present in the northern Sierra Madre Occidental and reinforces the need for continuing surveys in the barrancas region of Chihuahua.

Field Immobilization of Pygmy Spotted Skunks from Mexico

We immobilized 21 pygmy spotted skunks (Spilogale pygmaea), in the tropical deciduous forest at the Chamela Biological Station (Mexico) from October 1994 to May 1997, with a mixture of ketamine (KH) and xylazine (XH). Skunks were immobilized with a mean (+/- SD) dosage of 15.7 +/- 8.3 mg/kg KH and 8.1 +/- 4.3 mg/kg XH. Mean induction and recovery time (n = 21) were 1.7 +/- 1.6 and 34.2 +/- 12.2 min, respectively. One individual was immobilized with XH, induction time was 1 min, and recovery time was 45 min. Foaming salivation was observed in this animal. No other adverse effects were observed for the other animals in this sample.