The Puna Rhea (Rhea tarapacensis) is a large, flightless herbivorous bird found in the Andes Mountains of four countries, namely Argentina, Chile, Bolivia and Peru. Despite its ample distribution range, little is known about the ecological requirements of the species. In this work, the diet and food selection behaviour of the Puna Rhea in the Argentine Puna desert were analysed. From 2011 to 2014, throughout the dry and wet periods of each year, fresh faeces were collected and vegetation cover was simultaneously recorded. Diet composition was determined by microhistological analysis of the faeces and diet selectivity was established statistically by the Bonferroni method. The diet of the Puna Rhea was completely herbivorous and mostly folivorous, consisting of 51% of the plant species in the study area. This species was highly selective, consuming scarce shrub and herbaceous species and rejecting grasses or graminoids. The strongly selective foraging strategy presented by the Puna Rhea was therefore unrelated to the abundance of particular species but probably influenced by factors such as nutritional value, mainly in terms of fibre content and plant secondary compounds, and predation risk. Consequently, conservation efforts aimed at the Puna Rhea should be focused on maintaining the availability of the few preferred plant species and reducing possible competition with other generalist herbivores.

The Greater Rhea Rhea americana is a South-American flightless bird whose populations have decreased due to poaching and fragmentation of suitable habitats, and there has been an urgent need to carry out management practices to prevent local or regional extinctions. Several studies revealed that reintroduction might be an appropriate action for increasing the viability of wild populations of this species. Nevertheless, although this is a popular and useful conservation strategy, the animals to be released should be prepared against risks like predation and dispersion that could influence the post-release success. We evaluated the effect of an antipredator training applied to captive-bred Greater Rheas before they were released into the wild, on their dispersal and home range size and overlap, supposing that the trained animals would avoid dispersing into places with predators and, consequently, they would reduce their home range. We also studied the habitat use by the released rheas. Eleven trai...

Sex hormones and stress-related changes can be seasonally influenced. We investigate whether fecal glucocorticoid metabolite (FGM) levels can differ between male and female captive Greater Rheas during the breeding and non-breeding seasons. Over a 3-year-period, fresh fecal samples from 10 individuals (five of each sex) were collected during the breeding months (October, November, and December) and non-breeding months (April and June). A total of 960 samples were assayed using a commercial radioimmunoassay. Results showed that FGM levels (mean ± SE) were affected by the breeding season in a sex-dependent way. Male Greater Rheas showed significantly higher FGM levels in the breeding months than in the non-breeding months (13.44 ± 0.37 vs. 7.92 ± 0.1 ng/g feces, respectively). By contrast, females did not show FGM seasonal changes throughout the same sampling periods (7.55 ± 0.14 vs. 7.26 ± 0.73 ng/g feces). Moreover, during the breeding season months, males showed higher average FGM levels than females (13.44 ± 0.37 vs. 7.55 ± 0.14 ng/g feces, respectively), and no differences were found between sexes during the non-breeding season (7.92 ± 0.1 vs. 7.26 ± 0.73 ng/g feces, respectively). Our findings suggest that male Greater Rheas have a higher adrenocortical activity during the breeding season, which is probably indirectly related to the increased testosterone levels and agonist interactions that are also observed during that phase. Studies aimed to determine the appropriate sex ratio for captive rearing should be developed to minimize male agonist encounters and therefore improve welfare of the captive group. Zoo Biol. 34:71–75, 2015. © 2014 Wiley Periodicals Inc.