@article {Perez2022.10.28.513761,
	author = {Perez, Gustavo and Zhao, Wenlong and Cheng, Zezhou and T. D. Belotti, Maria Carolina and Deng, Yuting and Simons, Victoria F. and Tielens, Elske and Kelly, Jeffrey F. and Horton, Kyle G. and Maji, Subhransu and Sheldon, Daniel},
	title = {Using spatio-temporal information in weather radar data to detect and track communal bird roosts},
	elocation-id = {2022.10.28.513761},
	year = {2022},
	doi = {10.1101/2022.10.28.513761},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {The exodus of swallows from communal nighttime roosts is often visible as an expanding ring-shaped pattern in weather radar data. The WSR-88D network operated by the National Weather Service archives more than 25 years of data across 143 stations in the contiguous US. However, access to information about the roosting behavior of swallows is limited by the cost of manual annotation of these scans.We develop an AI system to detect and track swallow roosts in weather radar data. Our model is based on the Faster R-CNN architecture and is customized to incorporate multiple spatial and temporal channels in volumetric radar scans using novel adaptor layers. We systematically study the impact of network architecture and input representation for this task. We incorporate our detection outputs into an AI-assisted system with an interface for human screening to collect research-grade data about roosting behavior. We deploy the system to collect information from 12 radar stations in the Great Lakes region of the US spanning 21 years.The addition of temporal information improves roost detection performance from 47.0\% mean average precision to 54.7\%. Temporal information helps the model recognize the expanding pattern of roosts and filter false positives due to rain and static structures. Our system allowed the annotation of 15,628 roost signatures with 64,620 single-frame detections in 612,786 radar scans with 183.6 total hours of human screening, or 1.08 seconds per radar scan.Our AI-assisted system provides research-quality roost data with far less human effort than manual annotation of radar scans. The data contains critical information about the phenology and population trends of swallows and martins, a declining group of aerial insectivores. Our successful deployment to collect historical data for 8\% of the radar stations in the contiguous US lays the groundwork for continentscale analysis of swallow roosts, and provides a starting point for analysis of other family-specific phenomena in weather radar, such as bat roosts and mayfly hatches.Competing Interest StatementThe authors have declared no competing interest.},
	URL = {https://www.biorxiv.org/content/early/2022/10/31/2022.10.28.513761},
	eprint = {https://www.biorxiv.org/content/early/2022/10/31/2022.10.28.513761.full.pdf},
	journal = {bioRxiv}
}