Environmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual’s phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations. In order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length. Within each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length. Taken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions.

We studied effects of habitat structure on routine travel velocities, intermittent locomotion, and vigilance by the degu (Octodon degus), a diurnal rodent of central Chile. We predicted that travel speed, pauses during locomotion, and vigilance would be greater in open (riskier) than in shrub (safer) habitats. Video recordings of marked individuals in the wild were used to measure speed and other variables of spontaneous locomotion not triggered by predatory attack or any other noticeable stimulus during nonforaging periods. Time spent vigilant while foraging was also measured. Because degus use bare-ground runways for distant movements (e.g., between burrow openings and/or food patches), data on locomotion decisions were not confounded by effects of obstructive vegetation cover and/or resource abundance. When moving across the habitat between different feeding places, degus showed an intermittent pattern of locomotion, interrupting running events with short pauses. As predicted, travel speed and the duration of pauses between locomotion bursts were significantly greater in open habitats. Further, the duration of locomotion bursts between feeding sites or between feeding sites and burrows was significantly longer in open habitats. Our assumption that pauses and velocities are independent decisions was supported by the lack of correlation between pauses and speeds during locomotion events. During foraging, degus devoted more time to vigilance in open than in shrub habitats. The static position adopted by degus during pauses, the speeds attained during movements, and the concordance between pausing behavior and vigilance across habitats suggest that pausing has an antipredatory role and is not limited to orientation and/or physiological recovery. Our results support the view that degus perceive higher predation risk in open areas and that flexible movement behavior reflects an adaptive antipredator response.

Appropriate interventions to improve working equine welfare should be proposed according to scientific evidence that arises from different geo-cultural contexts. This study aims to assess and compare the welfare status of working horses in two administrative regions of Chile and to determine how owners perceive their horses. Horses’ welfare status was assessed through direct indicators (direct observation and clinical examination) and indirect indicators (an interview with the owner). Owners′ perceptions of their horses were determined through a discourse analysis of their statements. In total, 100 horses and 100 owners were assessed. Results showed a low prevalence of health problems and negative behavior responses among horses in the two regions evaluated. Significant associations were found between inadequate body condition and the absence of deworming, and between hoof abnormalities and a low frequency of shoeing. Between regions, significant differences were found in the presence of lesions and the person responsible for horseshoeing. In regards to the owners′ appreciations, two differing perceptions of working horses were found: a predominantly affective perception and a perception of the animal as a working instrument. Although the instrumental perception was more frequent in the Araucania region, the affective perception was widely shared by both owner populations. The results reveal a good welfare status in working horses and suggest that both affective and instrumental perceptions of these animals can coexist.

Parasites can exert selection pressure on their hosts through effects on survival, on reproductive success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies significantly among taxa. Various factors might explain the differences in infection among taxa, including habitat, climate, host density, the presence of vectors, life history and immune defence. Feeding behaviour can also be relevant both through increased exposure to vectors and consumption of secondary metabolites with preventative or therapeutic effects that can reduce parasite load. However, the latter has been little investigated. Psittaciformes (parrots and cockatoos) are a good model to investigate these topics, as they are known to use biological control against ectoparasites and to feed on toxic food. We investigated the presence of avian malaria parasites (Plasmodium), intracellular haemosporidians (Haemoproteus, Leucocytozoon), unicellular flagellate protozoans (Trypanosoma) and microfilariae in 19 Psittaciformes species from a range of habitats in the Indo-Malayan, Australasian and Neotropical regions. We gathered additional data on hemoparasites in wild Psittaciformes from the literature. We considered factors that may control the presence of hemoparasites in the Psittaciformes, compiling information on diet, habitat, and climate. Furthermore, we investigated the role of diet in providing antiparasitic secondary metabolites that could be used as self-medication to reduce parasite load. We found hemoparasites in only two of 19 species sampled. Among them, all species that consume at least one food item known for its secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, were free from hemoparasites. In contrast, the infected parrots do not consume food items with antimalarial or even general antiparasitic properties. We found that the two infected species in this study consumed omnivorous diets. When we combined our data with data from studies previously investigating blood parasites in wild parrots, the positive relationship between omnivorous diets and hemoparasite infestation was confirmed. Individuals from open habitats were less infected than those from forests. The consumption of food items known for their secondary metabolites with antimalarial, trypanocidal or general antiparasitic properties, as well as the higher proportion of infected species among omnivorous parrots, could explain the low prevalence of hemoparasites reported in many vertebrates.