Time–activity budget of greater rheas (Rhea americana, Aves) on a human-disturbed area: the role of habitat, time of the day, season and group size

Abstract

The aim of this study was to evaluate activitytime budget, habitat use and how seasonality and group size influence the expression of greater rhea behaviours. Greater rheas are threatened South American birds; habitat loss, predation and hunting are the main factors responsible for population declines. The study was conducted in farmlands within a matrix of commercial Eucalyptus plantation and remnants of natural habitats of cerrado vegetation (savannah-like) in southeastern Brazil. Rhea groups were located visually in different habitats visited monthly from January 2004 to December 2005. Time spent searching greater rheas in each habitat was equally distributed. Data were collected using scan sampling with instantaneous recording of behaviours every minute. The time-activity budget of greater rheas was influenced by habitat structure, time of the day, season and group size. Rheas spent more time in open areas than in forested areas (p<0.001). Vigilance behaviours were more displayed in forested areas, in the dry season and by solitary and small groups of birds. Resting behaviours occurred more often in open lands and within groups with more than three rheas. Food availability, good visibility and low human presence are the possible factors for the preference of greater rheas for pasturelands. The results support the resource availability hypothesis, where it is expected that habitats with a higher food availability will be more used by the animals, group size hypothesis, where the scarcity of resources will lead to smaller groups of animals and that forestry modifies greater rheas habitat use and behaviours.

TIME-OF-DAY BUT NOT SEASONALITY INFLUENCES FEEDING AND DIURNAL TIME ACTIVITY BUDGET OF ADULT RED-CAPPED LARK (Calandrella cinerea).

“…The findings however differed with those on the African Spoonbill (Platalea alba) studied in Lake Ziway (Ethiopia) (Moges & Balakrishnan, 2014) and the Somali ostrich (Struthio molybdophanes) in Samburu, Kenya (Mutiga et al, 2016) that showed that feeding significantly varied between seasons. This was also revealed in Greater Rheas in South eastern Brazil where timebudgets were influenced by seasonality (Azevedo et al, 2010). Another key activity related to feeding was searching for food, with search rates for the Red-capped Lark during the non-breeding season being higher than those during breeding season.…”

Effect of water level fluctuations on temporal-spatial patterns of foraging activities by the wintering Hooded Crane (Grus monacha)

“…The survey results from each 20 min period were used as an independent sample from which we calculated the foraging frequency (changes in behavior per unit of time), length of foraging time (the total time of foraging bouts) and foraging time budget [26,42,44]. Foraging success was quantified by analyzing the recordings of foraging birds and budgeting their time in foraging bouts [4].…”

“…The object of observation was usually selected as one adult in a group (≥3). All observations were performed from a relatively remote location to avoid the effect of the investigators on the behavior of the crane [42]. A voice recorder (DVR-990, JNN) was used to record its behavior for 20 min unless we lost sight of our focal bird.…”

“…Time-activity budgets of waterbirds in the winter could provide data on differential habitat use, evaluate responses of waterbirds to environmental conditions, make inferences about energy budgets and compare populations at different stages during the winter [55,56]. To study the behavioral patterns and time budgets for understanding the changes of habitat use, energy requirement and seasonal variation is of great importance [42].…”

Monitoramento não invasivo do estresse em animais silvestres mantidos em cativeiro

“…O comportamento estereotipado (pacing) foi observado em araraazul-de-lear (Anodorhynchus leari) que também expressaram outro comportamento anômalo, o de arrancar as próprias penas (Azevedo et al, 2016). Outros exemplos de comportamento esteriotipado observados em outras espécies de animais Neotropicais são: pacing em ema (Rhea americana) (Azevedo et al, 2010); pacing, andar em círculos e lamber as mãos repetidamente em cairara (Cebus olivaceus) (Tárano & López, 2015); e pacing em onça (Panthera onca, Sellinger & Ha, 2005).…”