Last October, when a boater spotted a river otter in Lake Merritt, residents rejoiced, celebrating the sighting of the semi-aquatic mammal as a sign that the lake’s ecosystem was making a comeback. River otters used to be ubiquitous in Northern California’s waters, but due to habitat loss, pollution, and hunters, their presence is now rare. Learn more about these elusive creatures during a presentation by the River Otter Ecology Project, hosted by Wild Oakland, on Thursday at PLACE for Sustainable Living (1121 64th St., Oakland). The project’s mission is to learn more about the behavior of river otters in order to preserve their habitats, and organizers will discuss how citizen scientists can help them collect data. If learning how to become an “otter spotter” isn’t enough to convince you to attend, we’ve got one word for you: OtterCams.