ct: An R package for camera trap data management and multi‐method ecological analysis

Camera trap surveys have become central to terrestrial wildlife monitoring, yet the route from raw detections to defensible inference is long, and in R it is walked with many single‐purpose packages. Researchers therefore spend disproportionate effort reshaping data and writing glue pipelines to move it between tools, and that effort peaks in density estimation for unmarked populations, where current guidance to compare several estimators is what the tooling makes hardest. In addition, there are few tools for behavioural and interspecific analyses of camera trap data. We present ct, an R package that carries an entire camera trap study from raw image metadata through cleaning, temporal‐independence filtering, effort accounting, modelling, and visualisation within a single tidy data structure. The package wraps and harmonises existing engines behind one consistent interface and extends the ecosystem with analyses it has lacked. At its core, ct places six density and abundance estimators for unmarked populations (camera trap distance sampling, random encounter model, time‐to‐event, space‐to‐event, instantaneous sampling, and the random encounter and staying‐time model) behind one interface, and documents for each the implementation it builds on, the data it requires, and the basis of its uncertainty interval. It also adds three analyses that, to our knowledge, no other camera trap package provides: an encounter response model that detects directed short‐term changes in one species' detection rate after another passes; a temporal shift statistic that measures how the diel activity window of a species moves between periods; and a spatial coverage surface that summarises where a species was detected. We demonstrate each capability on camera trap surveys from Benin and Taï National Park, Côte d'Ivoire. By standardising the workflow end to end, placing six density estimators behind one interface, adding new methods and providing data exploration utilities, ct lowers the technical cost of multi‐method camera trap ecology and brings reproducible analyses within reach of a much wider range of users.