Chaco Chachalaca (Ortalis canicollis, Wagler, 1830) feeding ecology in a gallery forest in the South Pantanal (Brazil)

Abstract

Cracids are generalist frugivores, which often exploit plant food resources such as flowers and leaves, mainly when fruit production declines. The Chaco chachalaca (Ortalis canicollis) is the most abundant cracid in the Pantanal (Brazil), and particularly common in the gallery forests. However, the factors related to their occurrence in this habitat type are unclear. In this study I describe the feeding habits and feeding niche breadth fluctuations of the Chaco chachalaca in relation to food resources abundance and diversity at the Miranda river gallery forest (Southern Pantanal). I also analyzed the relationships between Chaco chachalacas feeding activity and food resources abundance. This parameter (flowers and fruits) exhibited significant seasonal differences of abundance in which flowers were plentiful at the end of the dry, while fruits were abundant during the early wet season. However, food resources diversity to Chaco chachalacas exhibited no seasonal difference. Their feeding activity paralleled the availability of food resources, so that when some items were massively available an enhanced number of Chaco chachalacas foraged in the gallery forest, particularly during the prolonged dry season when they extensively used flowers and Genipa americana fruits. In fact, the Chaco chachalaca feeding niche breadth value presented low values in this period, while high values were common in the rest of the year. The flexible diet of this cracid, potentially favors their year round presence in the gallery forest, mainly during the prolonged dry season when the propensity for famine might be high. Since the Chaco chachalaca is among the largest and most abundant canopy frugivores in the gallery forest, it may contribute to forest regeneration, an underscored role due to the impact of annual floods and meandering dynamics on tree loss.Keywords: Cracidae, canopy phenology, Pantanal, Ortalis canicollis, frugivory. Ecologia alimentar do aracuã-do-pantanal (Ortalis canicollis) em uma floresta ripária no Pantanal Sul ResumoCracídeos são frugívoros generalistas que, também, exploram flores e folhas, sobretudo quando frutos são escassos. No Pantanal (Brasil), o aracuã-do-pantanal (Ortalis canicollis) é o cracídeo mais abundante, sendo particularmente comum em matas ciliares. No entanto, os fatores relacionados com sua ocorrência nesse habitat são desconhecidos. Nesse estudo eu descrevo tanto os hábitos alimentares quanto as variações de amplitude de nicho alimentar do aracuã-do-pantanal em relação à abundância e diversidade de recursos alimentares na mata ciliar do rio Miranda (Pantanal-Sul, Brasil). Também, analisei a relação entre atividade alimentar e oferta de recursos alimentares. Esse parâmetro (flores e frutos) exibiu variações significativas de abundância em que a produção de flores foi pronunciada de meados para o final da estação seca, enquanto a oferta de frutos foi elevada do início para meados da estação chuvosa. No entanto, a diversidade de recursos alimentares disponíveis para o aracuã-do-pantanal n...

Passive Acoustic Monitoring of Chaco Chachalaca (Ortalis canicollis) Over a Year: Vocal Activity Pattern and Monitoring Recommendations

“…Previous studies have suggested that Chaco Chachalaca may play an important role as a seed disperser since individuals pass intact seeds through the digestive tract; therefore, the species could be used as an indicator species of ecosystem quality (Caziani & Protomastro, 1994; Ragusa-Netto, 2015). Our current knowledge about the natural history of the species is almost entirely restricted to its diet and feeding ecology, which is mainly composed of leaves, fruits, flowers, and eventually arthropods (see Caziani & Protomastro, 1994; de Paiva et al, 2013; Ragusa-Netto, 2015). There is little information available on other ecological traits of the species, such as its vocal behavior and breeding ecology, (but see del Hoyo & Kirwan, 2020).…”

“…In this study, we employed passive acoustic monitoring over a complete annual cycle at three acoustic monitoring stations to monitor the vocal behavior of Chaco Chachalaca in the Brazilian Pantanal. We selected Chaco Chachalaca as the study model because (1) it is locally abundant in the Brazilian Pantanal (de Paiva et al, 2013; Nunes, 2015); (2) the species is expected to play an important role in forest regeneration (Ragusa–Netto, 2015); and (3) the population size of the species are decreasing, and further knowledge about its biology and monitoring protocols is desirable. Our specific goals were to (1) evaluate passive acoustic monitoring as a feasible technique to monitor the presence and vocal behavior of a cracid for the first time; (2) describe and analyze the patterns of diel and annual variations in vocal activity of Chaco Chachalaca to gain insights into the ecology of the species and propose effective sampling periods for monitoring the species; and (3) develop a species-specific effective monitoring protocol to monitor the Chaco Chachalaca using passive acoustic monitoring, in which we estimated the minimum number of recording days needed to estimate a reliable detected vocal activity rate (DVAR hereafter) for this species.…”

Diel and seasonal variation of Striped Cuckoo (Tapera naevia) vocalizations revealed using automated signal recognition

“…Based on seasonal changes in vocal activity, breeding seems to commence at the end of the dry season (August-October), coinciding with a period of high food abundance in the Brazilian Pantanal (Marques et al 2010(Marques et al , 2011 driven by the onset of rainfall (which occurred in September during the monitored annual cycle, Fig. 3), leading to elevated insect and fruit abundance (Wolda 1978, Ragusa-Netto 2015. This proposed breeding period aligns with the nesting period for most passerine birds, the hosts of the species, which breed between August and November in the study area (e.g.…”

Seasonality determines bird abundance, richness, and diversity among contrasting forest environments in the Northern Pantanal

“…Relative to food, the interplay between seasonality and environment heterogeneity can affect the resources availability in several aspects. For example, fruit production increases in flooding environments during the wet season and in non-flooding environments during the dry season (Sivério and Lenza 2010;Pilon et al 2015;Ragusa-Netto 2015). As a consequence, the seasonalitydependent patterns may largely influence bird abundance, richness, and diversity.…”