The culpeo or Andean fox (Lycalopex culpaeus, Molina 1782) is the second largest canid (4-13.8 kg) in South America (Jiménez et al., 1995; Jiménez and Novaro, 2004). It is distributed along the Andes Mountain range, from southern Colombia to Tierra del Fuego, Argentina (Jiménez et al., 1995). It is present at low altitudes in the Pacific and Atlantic coasts (Jaksic et al., 1980; Meserve et al., 1987; Medel and Jaksic, 1988; Marquet et al., 1993), and reaches the 4800 meters above sea level (m.a.s.l) in the Andes Mountains (Jiménez et al., 2008). Andean foxes occupy a large variety of habitats and environmental gradients: ranging from arid steppes (Meserve et al., 1987; Martínez et al., 1993; Arim and Jaksic, 2005), high steppes (Marquet et al., 1993; Johnson and Franklin, 1994; Walker et al., 2007; Palacios et al., 2012), dense shrubs (Iriarte et al., 1989), to altered ecosystems (Novaro et al., 2000; Pia et al., 2003) and pine reforested areas (Acosta-Jamett and Simonetti, 2004), or even rainforest (Jiménez et al., 2008).
This species is considered to be a trophic generalist (e.g. Walker et al., 2007). Indeed, culpeos exploit a wide variety of vertebrate, invertebrate and plant species according to their availability (Acosta-Jamett and Simonetti, 2004), although a degree of selectivity has been also reported (Meserve et al., 1987; Iriarte et al., 1989; Martínez et al., 1993; Corley et al., 1995). The culpeo is the most carnivorous of the Neotropical canids (Jiménez and Novaro, 2004), with a diet generally dominated by small mammals , especially rodents (Iriarte et al., 1989; Ebensperger et al., 1991; Jaksic et al., 1992, 1993; Castro et al., 1994; Pia et al., 2003; Correa and Roa, 2005; Achilles, 2007; Pia, 2013). Exotic lagomorphs (i.e. the European hare Lepus europaeus and the wild rabbit Oryctolagus cuniculus) can become important food sources for culpeos (Johnson and Franklin, 1994; Novaro et al., 2000; Pia et al., 2003; Walker et al., 2007; Pia, 2013; Rubio et al., 2013), and arthropods often appear in the culpeo’s diet (e.g. Corley et al., 1995; Correa and Roa, 2005; Guzmán-Sandoval et al., 2007; Walter et al., 2007). In addition, birds and reptiles can be considered prey, although studies show their contribution to the diet be variable (Achilles, 2007; Silva et al., 2005; Walker et al., 2007).
The culpeo is a brave predator able to attack large prey such as alpaca calves (Vicugna pacos), vicunas (Vicugna vicugna) and llamas (Lama glama), as observed in Bolivia (Franklin, 1982, in Donadio et al., 2012; Zacari and Pacheco, 2005). In Argentina Andean foxes also prey on lambs (Novaro et al., 2000, 2005), the species being persecuted due to damages produced on livestock (Jiménez and Novaro, 2004). Furthermore, and like other canid species, culpeos can consume different amounts of carrion (Novaro et al., 2000; Walker et al., 2007; Stucchi and Figueroa, 2010).
Plants also usually form an important part of the Andean fox’s diet (Jaksic et al., 1980; Ebensperger et al., 1991; Cornejo and Jiménez, 2001; Zapata et al., 2005). Plant consumption probably depends on the existing availability of prey (Castro et al., 1994; Silva et al., 2005). Andean foxes are known to be important seed dispersers of mesquite species (Prosopis flexuosa and P. pallida) (Cornejo and Jiménez, 2001; Maldonado et al., 2014) and pepper (Schinus molle) (Castro et al., 1994), although its role as an effective dispersant for other species is unclear (León-Lobos and Kalin-Arroyo, 1994; Silva et al., 2005).
Nevertheless, most studies dealing with the culpeo’s diet are from Chile and Argentina, so there are vast regions of South America where the feeding ecology of the species has been poorly studied, including entire countries (with their associated habitats and particular ecological conditions) where the diet is completely unknown. This is the case of Ecuador, where the species has recently been listed as Vulnerable (Tirira, 2011). The culpeo is distributed throughout the country, but it is generally considered to be a canid habiting highlands and cold areas (cloud forests and ‘paramos’), between 2600 and 4500 m.a.s.l., along the Andes range (Tirira, 2007). In this important region of the world no systematic and representative study examining the diet of the Andean fox has been published to date.
The aim of this study is to describe the trophic patterns of the Andean fox in the high Andes of southern Ecuador over a complete annual cycle, thus obtaining the first systematic outcome on the species feeding ecology in the country. In particular, it is intended: 1) to identify the culpeo’s prey species in the Podocarpus National Park and to describe the annual pattern of frequency in the diet of different prey groups; and 2) to evaluate the temporal variation during the year both in the consumption of prey groups and trophic diversity.