ct_availability: Temporal availability adjustment

In ct: Camera Trap Data Management and Multi-Method Ecological Analysis

Temporal availability adjustment

Description

Calculates availability correction factors by accounting for temporal variation in animal activity patterns and camera deployment effort. The availability rate represents the proportion of time animals are available for detection (Rowcliffe, et al., 2014; Howe et al., 2017) given their activity patterns and camera sampling effort.

Usage

ct_availability(
  times,
  format = NULL,
  sample = c("data", "model"),
  n_bootstrap = 1000,
  cam_daily_effort = 24,
  ...
)

Arguments

times	Vector of detection times, either in radians (0 - 2*pi) or formatted times (see format parameter).
format	Time format string (e.g., "%H:%M:%S", "%H:%M") if times need conversion to radians. Set to NULL if times are already in radians.
sample	Character string defining sampling method for bootstrapping errors (see details).
n_bootstrap	Number of bootstrap iterations to perform. Ignored if sample=="none"
cam_daily_effort	Daily operational hours of cameras (default = 24 for continuous operation).
...	Arguments passed on to ct_fit_activity weights A numeric vector of weights for each dat value. bandwidth Numeric value for kernel bandwidth. If NULL, calculated internally. adjustment Numeric bandwidth adjustment multiplier. bounds A two-element vector defining radian bounds at which to truncate. show Logical whether or not to show a progress bar while bootstrapping.

Value

A list containing data frame with:

• rate: Estimated availability rate (0-1)

• SE: Standard error of the availability rate

References

Howe, E. J., Buckland, S. T., Després-Einspenner, M. L., & Kühl, H. S. (2017). Distance sampling with camera traps. Methods in Ecology and Evolution, 8(11), 1558-1565. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1111/2041-210X.12790")}

Rowcliffe, J. M., Kays, R., Kranstauber, B., Carbone, C., & Jansen, P. A. (2014). Quantifying levels of animal activity using camera trap data. Methods in Ecology and Evolution, 5(11), 1170-1179. \Sexpr[results=rd]{tools:::Rd_expr_doi("doi:10.1111/2041-210X.12278")}

See Also

ct_fit_activity()

Examples

# Example with times already in radians
radian_times <- c(1.2, 3.4, 5.1, 0.5, 2.8)
ct_availability(radian_times, sample = "data")

# Example with formatted times
time_strings <- c("06:30", "18:15", "12:00", "23:45")
ct_availability(time_strings, sample = "data", format = "%H:%M")

# With bootstrap resampling
ct_availability(radian_times, sample = "data", n_bootstrap = 100)

ct documentation built on Oct. 22, 2026, 1:07 a.m.