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With fewer than 400 individuals remaining, critically endangered North Atlantic right whales ( Eubalaena glacialis; NARWs) embody New England’s foremost marine conservation challenge. In spring, a large portion of the NARW population visits Cape Cod Bay (CCB), MA, USA, a critical foraging area. Traditionally, aerial surveys have documented the abundance and distribution of NARWs in CCB. In this work, we employ passive acoustic monitoring to accomplish this task. This method offers a cost-effective and largely automated approach toward improved temporal resolution of observations. Regularly and universally produced by NARWs of all ages and sexes, the upcall vocalization serves as a proxy for NARW presence. This contact call’s highly stereotyped signal structure renders it optimal for detection through machine learning. From February to May 2019, five marine autonomous recording units (MARUs) continuously monitored the underwater soundscape in CCB. Manual upcall annotations across 20 days were used to evaluate a NARW automatic detector that ran over the full recording duration. Multiple arrivals across the MARUs were then matched through time-difference-of-arrival association. After estimating population-level calling rates, NARW density in CCB was calculated across the season. Results will be compared to visual survey observations conducted by the Center for Coastal Studies.

The ubiquity, importance, and sophistication of foraging behavior makes it an ideal platform for studying naturalistic decision making in animals. We developed a spatial patch-foraging task for rats, in which subjects chose how long to remain in one foraging patch as the rate of food earnings steadily decreased. The cost of seeking out a new location was varied across sessions. The behavioral task was designed to mimic the structure of natural foraging problems, where distinct spatial locations are associated with different reward statistics, and decisions require navigation and movement through space. Male and female rats generally followed the predictions of theoretical models of foraging, albeit with a consistent tendency to persist with patches for too long compared with behavioral strategies that maximize food intake rate. The tendency to choose overly-long patch residence times was stronger in male rats. We also observed sex differences in locomotion as rats performed the task, but these differences in movement only partially accounted for the differences in patch residence durations observed between male and female rats. Together, these results suggest a nuanced relationship between movement, sex, and foraging decisions.