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

Studying seasonal changes in the vocal activity of birds may shed light on the function of avian vocalizations and the phenology of life history events. Our current knowledge regarding the seasonality of the vocal behaviour of tropical birds in general, and avian brood parasites in particular, is very limited. Here, we employed passive acoustic monitoring with automated signal recognition to monitor the vocal behaviour of the Striped Cuckoo Tapera naevia over a complete annual cycle in the Brazilian Pantanal. We evaluated whether the pattern of vocal activity differed between the two main vocalizations of the species (sem-fim and wee-series songs) and whether vocal activity varied with time of day and season. The diel pattern of vocal activity for both vocalization types showed a bimodal pattern, with the first peak of vocal activity in the few hours after sunrise and the second peak before sunset, in agreement with prior studies in other cuckoos. The sem-fim song was also produced during the night, while the wee-series song was produced only during the day. Both vocalization types showed clear seasonality and were produced between mid-June and mid-February. Seasonal changes in vocal activity suggest that the Striped Cuckoo breeds during the dry season and leaves the study area during the flooding period. The seasonal pattern of the wee-series song showed strong seasonality, with 90% of these calls detected in September and October, whereas the sem-fim song showed weaker seasonality, with 80% of the calls detected during the July–October period. Our study indicates that automated signal recognition might be a reliable tool for monitoring cuckoos. Further research could evaluate whether the different seasonal patterns of the sem-fim and wee-series songs of the Striped Cuckoo are related to different functions.We greatly appreciate financial support from: the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 01; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Bonn, Germany. Furthermore, we thank the SESC Pantanal, Mato Grosso, for permission to conduct research on their property and their logistical help with our fieldwork. C.P.G. acknowledges support from Ministerio de Educación y Formación Profesional through the Beatriz Galindo Fellowship (Beatriz Galindo – Convocatoria 2020)

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

Chaco Chachalaca (Ortalis canicollis) is a declining Neotropical bird, for which our current knowledge about its natural history is very limited. Here, we evaluated for first time the utility of passive acoustic monitoring, coupled with automated signal recognition software, to monitor the Chaco Chachalaca, described the vocal behavior of the species across the diel and seasonal cycle patterns, and proposed an acoustic monitoring protocol to minimize error in the estimation of the vocal activity rate. We recorded over a complete annual cycle at three sites in the Brazilian Pantanal. The species was detected on 99% of the monitoring days, proving that this technique is a reliable method for detecting the presence of the species. Chaco Chachalaca was vocally active throughout the day and night, but its diel activity pattern peaked between 0500 and 0900. The breeding season of Chaco Chachalaca in the Brazilian Pantanal, based on seasonal changes in vocal activity, seems to occur during the last months of the dry season, with a peak in vocal activity between August and October. Our results could guide future surveys aiming to detect the presence of the species, both using traditional or acoustic surveys, or to evaluate changes in population abundance using passive acoustic monitoring, for which recorders should be left in the field for a minimum period of nine days to obtain a low-error estimate of the vocal activity of the species. Our results suggest that passive acoustic monitoring might be useful, as a complementary tool to field studies, for monitoring other cracids, a family with several threatened species that are reluctant to human presence.We greatly appreciate the financial support from the following institutions: the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 01; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Bonn, Germany

Automated signal recognition as a useful tool for monitoring little-studied species: The case of the Band-tailed Nighthawk

Passive acoustic monitoring, when coupled with automated signal recognition software, is a useful technique for monitoring vocally active taxa. In this study, we evaluated the utility of automated signal recognition to gain insights into the ecology of little-studied species. For this purpose, we selected an avian family, Caprimulgidae (nightjars), composed of cryptic and nocturnal species, and focused the study on a Neotropical wetland, the Brazilian Pantanal. We reviewed the number of publications, observations, and recordings available for each nightjar inhabiting the Brazilian Pantanal and the Band-tailed Nighthawk (Nyctiprogne leucopyga) was identified as the species with the least information available. We employed automated signal recognition software to study the vocal behavior of this species over a complete annual cycle in the Pantanal. Previous knowledge about the ecology of this species is based on general descriptions and anecdotal observations. Our findings corroborate that the Nighthawk is a resident species of the Brazilian nightjars, and according to seasonal changes in vocal activity, the breeding season extends from July to October. The breeding period starts at the end of the dry season (July–August), and the nesting period may occur at the beginning of the wet season and following the first rains, which is a period of maximum insect food availability. The vocal activity of the Nighthawk was restricted to the nocturnal period and was maximum at dusk. That preference for dusk is in disagreement with the pattern described for the other four nightjars in the study area, which highlights the importance of performing species-specific studies and avoiding drawing any conclusions about the activity pattern of a species based on the genus or family to which it belongs to. Automated signal recognition software was able to detect over three quarters of the songs annotated by a human on a subset of sound recordings, therefore proving its utility for monitoring the Band-tailed Nighthawk.We greatly appreciate financial support from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 01; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Bonn, Germany

The sound of the illegal: Applying bioacoustics for long-term monitoring of illegal cattle in protected areas

Passive acoustic monitoring coupled with automated signal recognition software has been widely used in recent years as an effective and affordable tool for wildlife monitoring and to combat illegal activities within protected areas. Here, we evaluate this technique to monitor the patterns of illegal cattle occurrence in the Brazilian Pantanal over a complete annual cycle. We aim to provide one of the first assessments of the performance of automated signal recognition software to detect ungulates. Cattle occurrences reached their maximum during the end of the dry season when lowland areas provide excellent pastures for cattle. In contrast, cattle occurrences were very low during the rainy season when the study area was seasonally inundated. Automated software was an efficient tool that was able to detect approximately three-quarters of cow calls within the recordings. Passive acoustic monitoring can be used to direct patrols to areas where illegal activities, such as cattle and poaching or logging, have been confirmed, which could be a method that would be especially well suited for remote areas, such as tropical forests. Future studies should evaluate whether there is a relationship between cattle grazing intensity and its associated impacts on wildlife and flora. Rapid advances in automated recognition and the recent development of low-cost recorders foresee a new era of acoustic ecology for improved conservation in the short term.This study is part of the biodiversity monitoring project Sounds of the Pantanal - The Pantanal Automated Acoustic Biodiversity Monitoring of INAU/CO.BRA, Cuiabá, Mato Grosso, Brazil, which was conducted under SISBIO permit no. 39095 (KLS). We greatly appreciate the financial support provided by the following institutions: the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 01; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Bonn, Germany

TEMPORAL DYNAMICS IN PANTANAL HUMMINGBIRD ASSEMBLAGES IS TRIGGERED BY FLOOD PULSE

Abstract ∙ Hummingbirds (Trochilidae) are highly specialized New World birds that depend on nectar as their major food source. In response to seasonal food limitations, many trochilids develop dispersal and long-distance migration patterns, but these patterns are understudied for many continental South American species. In this study, conducted in the Brazilian Pantanal, we investigated the movement patterns of hummingbirds in a highly variable environment, where an annual flood pulse leads to four distinctive seasonal periods (high water, receding water, dry period, and rising water). Our objective was to verify how these four periods affected the hummingbird community according to habitat occupation in savannas or forests. This study was conducted in the northeastern Pantanal of Mato Grosso, Brazil (16° 39'S, 56°47'W, 119–131 m a.s.l.), covering two annual inundation periods (2014–2016). Data were collected using mist net sampling. Two migrant and seven resident species were identified. The results indicated significant differences in hummingbird species richness and abundance between habitats; savanna habitats were the richest habitats during rainy seasons (rising and high water). Higher hummingbird abundance in these seasonal periods was seemingly related to higher food availability since these seasons corresponded to the main flowering period of ornithophilous plants and other angiosperms

Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, daily rainfall was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.This research was funded by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–Brasil (CAPES), Finance Code 01; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Bonn, Germany

Reproduction phenology of a high conservation priority cracid – the Bare‑faced Curassow (Crax fasciolata; Aves, Galliformes, Cracidae)

Knowledge of the reproductive biology of Bare-faced Curassows (BFC) from their natural habitats is very limited. Our study covers a two-and-a-half year breeding phenology on BFC in the northern Pantanal (Mato Grosso State, Brazil) with the main objective of collecting information on reproduction biology to contribute to future conservation management strategies of this cracid, which received a recent status of "High Conservation Priority". The study was conducted at the SESC Pantanal, Baía das Pedras, Mato Grosso, Brazil (16°29′55″S, 56°24′46″W), a private protected area of approximately 4,200 ha. Between July 2015 and December 2017, 37 sampling locations were monitored with camera traps placed in a regular grid with a spacing of 1 km. Offspring were detected at least once at 8 locations, namely, in March, April, and May 2016 and in June, July, October, and November 2017, always together with parent(s). Territorial overlap between different family groups was detected. The camera trap dataset was supplemented by data from Citizen Science Projects (i.e., eBird) and the Global Biodiversity Information Facility (GBIF). Based on feather developmental stages and body size, offspring were classified into different age classes. Age determination indicates that breeding occurs year-round in the northern Pantanal region, supported by eBird and GBIF data. The use of a grid-based design for future camera-trapping studies of BFCs is strongly recommended. Our study is of biological relevance for conservation management projects since data were collected in an area with low anthropogenic disturbance and intact ecosystem services

Surfactant Concentration Regime in Miniemulsion Polymerization for the Formation of MMA Nanodroplets by High-Pressure Homogenization

This article focuses on the adequate surfactant concentration regime in which MMA droplets are stabilized sufficiently against coalescence during high-pressure homogenization but still no diffusion processes from droplets to micelles take place in the polymerization. Monomer miniemulsions with different surfactant concentrations were prepared with different energy inputs. Emulsions result that depend either on the surfactant concentration or on the energy input of the homogenization process. For both cases, the occupancy of the interface is compared as a function of the droplet size. It is shown that the surfactant concentration needed for the stabilization of a specified interface area decreases with increasing droplet size. For the dependence of droplet size on the energy input, it is shown that more surfactant can be applied before emulsion polymerization starts, but the applicable surfactant concentration is lower than the cmc and also depends on droplet size

Avian biodiversity assessment studies in a Neotropical wetland – the combination of sampling methods makes the difference

In studies of avian diversity, many different methods have been applied. Since methodological approaches may affect research results, the choice of a given methodology must be consistent with the scientific objectives. The aim of this study was to investigate how different methodologies with their intrinsic limitations help detect and monitor birds to evaluate how they complement each other in the survey of species. Three different assessment methods, mist nets, point counts, and autonomous acoustic recordings were used to serve this purpose in a study of different Pantanal habitats, such as savannas and forests. The point counts detected more species (126 species) than the two other methods autonomous acoustic recordings (113 species) and mist nets (79 species). We observed significant differences in the number of species detected by mist nets and the other two methods. Each survey method identified exclusive species. When comparing habitats, all three methods showed significant differences in bird species composition. Savannas were richer in bird species than forests, and replacement was the main driver responsible for the differences in beta diversity between the habitats. The three methodologies, when applied together, proved to be complementary in avian species detection