Karl-L. Schuchmann

Automated acoustic detection of Vanellus chilensis lampronotus

Automated acoustic recognition of Southern Lapwing in real-world soundscapes.Recognizer of Vanellus chilensis vocalizations and their start and end timestamps.Log-likelihood ratio estimator with temporal post-processing of the output scores.Computer-assisted analysis of daily and hourly acoustic activity patterns.Non-intrusive monitoring of presence/absence and activity patterns. Traditional human-observer-based biological surveys are expensive. Therefore most biodiversity studies are implemented only periodically, for short periods, and predominantly during daytime and under favorable weather conditions. Automated data acquisition and analysis can overcome these shortcomings and facilitate continuous monitoring. Here we report on the development of an automated acoustic recognizer for Southern Lapwing Vanellus chilensis lampronotus vocalizations, a first for this species. The recognizer is a species-specific information retrieval agent, which searches throughout long audio recordings in order to detect and timestamp call events of the target species. The recognizer relies on a log-likelihood ratio estimator, based on a Gaussian Mixture Model-Universal Background Model (GMM-UBM), complemented with purposely-developed temporal post-processing that incorporates domain knowledge about the structure of V. chilensis vocalizations. Validation experiments with real-field recordings of complex soundscapes indicate that the recognizer is sensitive enough to register V. chilensis call events with sound levels down to -30dB and recognition accuracy of up to 85.6%, at zero false positive rates. The recognizer is considered a valuable tool for computer-assisted analysis of hourly and daily acoustic activity of V. chilensis over extended periods of time, as it offers an indispensable support to long-term monitoring studies and conservation efforts in the Pantanal region.1INAU Project 3.14 Monitoring Bioindicators and Migratory Birds in the Pantanal. Applied Acoustomics - a Tool for Bio-sustainability Assessment, INAU Lab. 3 - Biodiversity and Ecological Processes (INAU: www.inau.org.br; 2011-2014) - Program CsF (www.cienciasemfronteiras.gov.br/web/csf).1

Audio parameterization with robust frame selection for improved bird identification

Audio parameterization method with robust frame selection.Automated acoustic recognition of 40 bird species.HMM-based bird identification. A major challenge in the automated acoustic recognition of bird species is the audio segmentation, which aims to select portions of audio that contain meaningful sound events and eliminates segments that contain predominantly background noise or sound events of other origin. Here we report on the development of an audio parameterization method with integrated robust frame selection that makes use of morphological filtering applied on the spectrogram seen as an image. The morphological filtering allows to exclude from further processing certain audio events, which otherwise could cause misclassification errors. The Mel Frequency Cepstral Coefficients (MFCCs) computed for the selected audio frames offer a good representation of the spectral information for dominant vocalizations because the morphological filtering eliminates short bursts of noise and suppresses weak competing signals. Experimental validation of the proposed method on the identification of 40 bird species from Brazil demonstrated superior accuracy and faster operation than three traditional and recent approaches. This is expressed as reduction of the relative error rate by 3.4% and the overall operational time by 7.5% when compared to the second best result. The improved frame selection robustness, precision, and operational speed facilitate applications like multi-species identification of real-field recordings.

Automated Sound Recognition Provides Insights into the Behavioral Ecology of a Tropical Bird

Computer-assisted species recognition facilitates the analysis of relevant biological information in continuous audio recordings. In the present study, we assess the suitability of this approach for determining distinct life-cycle phases of the Southern Lapwing Vanellus chilensis lampronotus based on adult vocal activity. For this purpose we use passive 14-min and 30-min soundscape recordings (n = 33 201) collected in 24/7 mode between November 2012 and October 2013 in Brazil’s Pantanal wetlands. Time-stamped detections of V. chilensis call events (n = 62 292) were obtained with a species-specific sound recognizer. We demonstrate that the breeding season fell in a three-month period from mid-May to early August 2013, between the end of the flood cycle and the height of the dry season. Several phases of the lapwing’s life history were identified with presumed error margins of a few days: pre-breeding, territory establishment and egg-laying, incubation, hatching, parental defense of chicks, and post-breeding. Diurnal time budgets confirm high acoustic activity levels during midday hours in June and July, indicative of adults defending young. By August, activity patterns had reverted to nonbreeding mode, with peaks around dawn and dusk and low call frequency during midday heat. We assess the current technological limitations of the V. chilensis recognizer through a comprehensive performance assessment and scrutinize the usefulness of automated acoustic recognizers in studies on the distribution pattern, ecology, life history, and conservation status of sound-producing animal species.

Acoustic bird activity detection on real-field data

We report on a research effort aiming at the development of an acoustic bird activity detector (ABAD), which plays an important role for automating traditional biodiversity assessment studies --- presently performed by human experts. The proposed on-line ABAD is considered an integral part of an automated system for acoustic identification of bird species, which is currently under development. In particular, taking advantage of real-field audio recordings collected in the Hymettus Mountains east of Athens, we investigate the applicability of various machine learning techniques for the needs of our ABAD, which is intended to run on a mobile device. Performance is reported in terms of recognition accuracy on audio-frame level, due to the restrictions imposed by the requirement of run-time decision making with limited memory and energy resources. We report recognition accuracy of approximately 86% on a frame level, which is quite promising and encourages further research efforts in that direction.

Collecting history of the hummingbird genera Chaetocercus Gray, 1855 and Lophornis Lesson, 1829

We examined the Chaetocercus and Lophornis holdings of 21 European, US and South American avian collections. Only skin specimens with exact (to the year) collecting dates and reliable locality data on their labels, which could be checked personally, were analysed. We located 466 Chaetocercus and 373 Lophornis specimens collected between the years 1859 and 1999. The vast majority of these records are old ones, dated between 1880 and 1960: 93% of the Chaetocercus and 82% of the Lophornis study skins. Less than 1% of all specimens was obtained after 1990. Potential explanations for our findings, such as declining population levels of these hummingbird genera, historically changing collecting activities regarding commercial dealers and collecting techniques, and legal collecting restrictions are discussed. Our findings reflect a general trend of decreasing collecting activities worldwide.

Biogeography and taxonomy of racket-tail hummingbirds (Aves: Trochilidae: Ocreatus ): evidence for species delimitation from morphology and display behavior

We analyzed geographic variation, biogeography, and intrageneric relationships of racket-tail hummingbirds Ocreatus (Aves, Trochilidae). Presently, the genus is usually considered monospecific, with O. underwoodii including eight subspecies (polystictus, discifer, underwoodii, incommodus, melanantherus, peruanus, annae, addae), although up to three species have been recognized by some authors. In order to evaluate the current taxonomy we studied geographic variation in coloration, mensural characters, and behavioral data of all Ocreatus taxa. We briefly review the taxonomic history of the genus. Applying the Biological Species Concept, species delimitation was based on a qualitative-quantitative criteria analysis including an evaluation of character states. Our results indicate that the genus should be considered a superspecies with four species, the monotypic Ocreatus addae, O. annae, and O. peruanus, and the polytypic O. underwoodii (including the subspecies underwoodii, discifer, incommodus, melanantherus, polystictus). In this taxonomic treatment, O. annae becomes an endemic species to Peru and O. addae is endemic to Bolivia. We recommend additional sampling of distributional, ethological, and molecular data for an improved resolution of the evolutionary history of Ocreatus.

Lerneca inalata beripocone subsp. nov. (Orthoptera: Phalangopsidae; Luzarinae): a new taxon for the northern Pantanal of Brazil

The first record of the Orthoptera species Lerneca inalata for Brazil is presented here. The taxon is represented by a new subspecies Lerneca inalata beripocone subsp. nov. (Phalangopsidae, Luzarinae), collected in the Pantanal of Poconé, Mato Grosso, Brazil. This work includes morphological and morphometric data as well as descriptions of female genitalia and calling song. The new subspecies has as diagnostic features the male genitalia with six ventral spines on the B sclerite, the first spine having a subtle bifurcation; the mid-region of the strongly sclerotized pseudepiphallus; inclination of C sclerite with slightly concave curvature; tegmina-length ratio and the speculum (syn. mirror) width approximately three times the length of the apical area. The description of the female genitalia and the calling song is presented for the first time for the species Lerneca inalata. A distribution map covers the local occurrence of its subspecies.

The life history of the Long-wattled Umbrellabird Cephalopterus penduliger in the Andean foothills of north-west Ecuador: leks, behaviour, ecology and conservation

Summary The rare and threatened Long-wattled Umbrellabird Cephalopterus penduliger inhabits the canopy and mid-storey level of humid to wet foothill and montane forests (150-1,800 m) of the Andean slopes of south-west Colombia and western Ecuador. Here we report on male activity pattern and display behaviour observed at one of two leks recently discovered in the vicinity of Playa de Oro, Rio Santiago, Esmeraldas Province, north-west Ecuador. Courtship behaviour of C. penduliger is compared with the Central American and Amazonian congeners (Bare-necked Umbrellabird C. glabricollis and Amazonian Umbrellabird C. ornatus). The lek of C. penduliger was active during the whole study period (February 1997 to January 1998), but both lek structure and daytime activity pattern changed markedly within the observation period.

Reproduction and agonistic behavior of black skimmers (Rynchops niger) in a mixed-species colony in the Brazilian Pantanal

ABSTRACT Black skimmers (Rynchops niger) are colonial waterbirds in Nearctic and Neotropical regions. They often breed in mixed colonies with terns. This work analyzes the reproductive biology of skimmers within a colony including large-billed terns (Phaetusa simplex) and yellow-billed terns (Sternula superciliaris), located along the Cuiabá river in the Brazilian Pantanal, during July–September 2015. We focused on nesting parameters, timing of reproduction, nest survival, predation risk, and agonistic behavior. Skimmer nests (n = 31) were not aggregated (R = 0.40); mean nest distance was 6.91 ± 3.39 m. Incubation lasted on average 21.6 ± 1.6 days. Nest survival was low (3.2%) due to predation and abandonment, with the green iguana (Iguana iguana) as major predator of eggs. Aggressive behavior included chase and turn-off flights and mainly involved birds of prey (26.5%) followed by jabirus (Jabiru mycteria; 18.2%). The low number of nesting terns (n = 3), which can act as protector species, may have negatively impacted the fledging success of R. niger. Reproductive parameters and the complexity of behavioral interactions in such mixed colonies should be further studied in the Pantanal as model cases for ecological/ethological adaptations of colonial breeders under the impact of a seasonally fluctuating water regime.

Tegmina-size variation in a Neotropical cricket with implications on spectral song properties

This study evaluates the relationship between shape and size of tegmen, harp, mirror, and spectral range of calling song frequency of a Neotropical cricket subpopulation (Lerneca inalata beripocone. In addition, we compare intraspecific morphological divergence and calling song properties between individuals from different sites of the Pantanal of Poconé, Mato Grosso, Brazil. Regression analysis showed that the dominant and maximum calling song frequencies were negatively correlated with tegmen size, i.e. frequencies are either lower or higher depending on the corresponding size variation in resonance structures of the forewings. Canonical variable analysis demonstrated marked intraspecific differences in morphometric characters between localities of a L. inalata subpopulation c. 35 km apart (SESC-Pantanal Advanced Research Base and Pouso Alegre Farm, Mato Grosso, Brazil). Lerneca inalata beripocone at SESC had larger forewings than conspecifics from Pouso Alegre Farm. These morphological variations of wing properties related to reproductive behaviours were interpreted as fitness parameters, likely shaped by restricted gene flow during temporal habitat isolation episodes. Such isolation patterns occur in the Pantanal wetlands for several months during the annual hydrological cycle.