Here is a small sample of projects that have used early development versions of XBAT, in no particular order: Banded Wren Communication, Humpback Whale Conservation, Ivory-Billed Woodpecker Search, Black-Capped Vireo Conservation, Flight-Call Research.
Banded Wren CommunicationWhat they're really saying!
Male banded wrens (Thryothorus pleurostictus) sing with relatively high rates and diversity. Each bird has a repertoire of about 25 discrete song types, with some variation in types both within and between males.
We record wild birds in Santa Rosa National Park, Costa Rica, during the entire dawn chorus for multiple days, and then locate and classify each song in the resulting recordings. Manually, this is a time-consuming endeavour. The XBAT data template detector is an automated tool for locating and classifying songs in batches of large digital sound files, speeding the process considerably.
Templates based on an exemplar of each song type in a male's repertoire give highly accurate (few misclassified types) and objective (based on correlation thresholds) classification into types, and most songs are detected. Additionally, people without experience in distinguishing banded wren song types find XBAT to be a valuable tool for processing and learning these songs.
Humpback Whale ConservationTrying to get their message across!
Male humpback whales (Megaptera novaeangliae) sing very frequently at their breeding grounds. Many preferred breeding areas are conservation hotspots protected by marine parks, and the whale watching industry has flourished in those sites. Multiple males can sing continuously for many hours to mediate mating. Concerns about the impact of boat traffic and boat noise have been aroused, especially in these sensitive breeding areas where whales concentrate to reproduce.
We record sounds in the Abrolhos National Marine Park, Brazil, during the breeding season from June to November, and then detect and locate singing males to learn about their distribution in space and time. Boat noise is also recorded.
Using the long term spectrogram tool in XBAT we can identify and log boat noise events over 24-hours and explore the effects of these on the vocal activity of singers. Manual processing of our large data set of almost 9 months of continuous recordings over 3 years would be prohibitive. XBAT's data template detector, source locator, and long term spectrogram tools automate detecting and locating multiple singers and boat noise in batches, visualizing recordings over long periods of time, making data exploration and analysis easier and faster.
Ivory-Billed Woodpecker SearchThe search!
The ivory-billed woodpecker (Campephilus principalis) is the largest woodpecker in the North America, and the third largest in the world. Until recently, the species was widely presumed to be extinct. However, in 2004 a series of brief sightings in eastern Arkansas led to a massive search effort to find evidence of ivory-bills surviving in the region.
The search has included a large scale acoustic recording effort because the most reliable way of finding ivory-bills in their dense forest habitat is by listening for their distinctive sounds. We have used autonomous digital audio recorder units (ARUs) to record over 20,000 hours of audio from over 200 sites throughout hundreds of thousands of acres in the Cache River and White River National Wildlife Refuges.
Ivory-billed woodpeckers are known to produce two distinctive acoustic signals. One is a harmonically rich, nasal-sounding vocalization — usually transcribed as kent. Only one set of recordings of these calls was ever made, from two individual birds in the Singer Tract in Louisiana in 1935 here. The ivory-bill's other characteristic sound was never definitively recorded, and is known only from written descriptions: a loud, rapid double knock made by two strikes of the bird's bill against a wooden substrate, apparently used as a display, alarm, and contact signal. Similar double knock display drums are produced by most other species of Campephilus woodpeckers here.
We have used XBAT's data template detector to search for sounds similar to the kent notes in the 1935 recording and to recordings of double knocks from other Campephilus species. XBAT's data template detector and its facilities for interactively reviewing detection results have made it possible to review this very large data set in a reasonable time frame and have enabled us to find a few likely needles in the haystack of data here.
Black-Capped Vireo ConservationListen Carefully!
The endangered black-capped vireo (Vireo atricapilla) sings a complex song made up of a wide variety of distinctive sound elements. The number of distinct sound elements in its repertoire is about ten times larger than that of other vireos.
One of the largest remaining populations of this species breeds at Fort Hood in central Texas. To protect this endangered species Department of Defense resource managers need to monitor vireo populations in order to implement conservation strategies. Our analysis of recordings of these birds is enabling the development of techniques for the large-scale acoustic monitoring and censusing of black-capped vireos. These recordings are also helping us to investigate the potential impact of human-generated sounds on black-capped vireo singing behavior.
We have recorded more than 8 terabytes of audio data over four years. Using XBAT's data template detection functions, we are working with a collection of black-capped vireo sound elements to design acoustic sampling strategies that can be used for monitoring efforts throughout the geographic range of this endangered species.
Flight-Call ResearchI can't see you. Are you still there?
The sound of flight-calls is a staple of many spring and autumn nights, well known to ornithologists, astronomers, and keen observers alike. These calls are species-specific and are generally single notes that vary in frequency, degree of modulation, and duration
Although their existence is well-documented, there are many gaps in our knowledge of flight-calls. In many parts of the world, flight-calls are unstudied; even in North America species that rarely vocalize are still poorly known. Further, basic facts about flight-calling behavior such as: evolutionary and ontogenetic history, degree of individual variation in calls, calling rates, and even its function, remain largely unknown.
As part of my dissertation research, I am collaborating with researchers in the Bioacoustic Research Program at Cornell and at Powdermill Avian Research Center to address some of the gaps in our knowledge.
XBAT is a wonderful tool for research on flight-calls, and I have used it to measure more than 15,000 flight calls of 48 species of North American migrant warblers as part of a project to study individual variation, evolutionary history, and ecology of flight-calls in these birds. XBAT is also useful for detecting flight-calls embedded in lengthy nocturnal recordings. The speed with which this program opens files, as well as the speed with which it is possible to measure and to detect calls, is staggering. To date, I have produced nearly 12,000 hours of nocturnal recordings, and without such a program these data would take years to analyze.
Beyond evolutionary and ecological interest, there is also keen interest from the conservation community in using flight calls to monitor migrant populations and their phenology. Having a tool such as XBAT to study thousands of hours of flight-calls efficiently and effectively is making such conservation applications increasingly possible.