Interspecific Competition inGrallariaAntpittas: Observations at a Feeder

Relative Abundance and Microhabitat of Four Sympatric Antpittas in an Interandean Valley of Southern Ecuador

“…We found the Undulated Antpitta occupying as well a unique microhabitat with characteristics corresponding to a mature forest and a forest floor made up of abundant leaf litter. This is generally consistent with what is described by ; however, there are some differences between our results and the typical habitat described in , as the Undulated Anpitta is most often thought to occur in areas of second growth vegetation, such as shrubs and thickets of bamboo (Fjelsa & Krabbe 1990, Kattan & Beltrán 1999, Snow et al 2015. However, considering that this species has a large distributional range from Venezuela to Bolivia (Greeney 2008), we suspect that there could be a geographical variation in habitat requirements for this species, and more studies are needed across its range to have a clearer idea of the habitat association occupied by it.…”

“…First, the magnitude of competition in birds could vary over time, perhaps increasing during breeding periods or when the abundance of resources decreases (Morrison & With 1987, Wilson 2010, Pontón-Cevallos et al 2016. Studies of competition in antpittas are still scarce, but Snow et al (2015) suggested that there could be temporal variation in interspecific competition among species. Hence, if the competitive interactions vary in time among antpittas, a temporal dynamic in niche partitioning is also to be expected.…”

“…They are terrestrial insectivores that commonly feed by searching for prey on the forest floor by tossing dead leaves and other organic material with their bills , Krabbe & Schulenberg 2018. In most areas of the Andes, it is possible to find several species of the genus living in sympatry, therefore presenting high levels of niche overlap (Graves 1987, Freile et al 2010, Snow et al 2015; for example, a study of territory mapping of birds in the Andes of Colombia even found high interspecific overlap in territorial space use of five species of antpittas (Kattan & Beltran 2002) The Llaviuco Valley is a high elevation, interandean valley located in Cajas National Park, southern Ecuador. Here, four species of Grallaria occur in sympatry: the Rufous Antpitta (Grallaria rufula), the Chestnut-crowned Antpitta (Grallaria ruficapilla), the Undulated Antpitta (Grallaria squamigera), and the Tawny Antpitta (Grallaria quitensis) (Freile et al 2010, Astudillo et al 2015, eBird 2018.…”

“…Here, four species of Grallaria occur in sympatry: the Rufous Antpitta (Grallaria rufula), the Chestnut-crowned Antpitta (Grallaria ruficapilla), the Undulated Antpitta (Grallaria squamigera), and the Tawny Antpitta (Grallaria quitensis) (Freile et al 2010, Astudillo et al 2015, eBird 2018. These species differ in their body size and bill measurements (Table 1; Greeney 2018), which could facilitate niche partitioning among species (Schoener 1974, Okuzaki et al 2010, Snow et al 2015; however, there are no detailed studies about the mechanisms promoting their coexistence (but see Kattan & Beltran 1999).…”

Species distribution models for Peruvian plantcutter improve with consideration of biotic interactions

“…Biotic interactions are processes that link populations of two or more species, and can be classified in terms of cost and benefit to species pairs: in mutualism, both populations benefit, whereas under competition and parasitism, one benefits and the other suffers. On a deeper time scale, coevolution is a phenomenon of evolutionary co-adaptation between two species: changes in one species create selective pressures on the other (Heikkinen et al 2007, Snow et al 2015.…”