Does sentinel presence improve foraging success? A study in a cooperative breeder

In various cooperative breeding species, a group member often sentinels from a prominent position that enables early detection of approaching predators and then utters alarm calls to which the other group members react immediately. We tested in the cooperatively breeding Arabian babbler (Argya squamiceps), whether in the presence of a sentinel the other group members forage for longer or more effectively. In natural observations, at different distances from the shelter and in different group sizes, we found no effect of sentinel presence on foraging time. Likewise, in a giving-up density (GUD) experiment with artificial food patches containing mealworms at each of three different distances from the shelter, fewer mealworms were consumed further from the shelter, irrespective of whether a sentinel was present or not during foraging. While foragers react to a sentinel’s alarm calls when a predator approaches, our findings indicate that Arabian babbler foragers do not improve their foragin..., Data were collected in field observations as well as throughout an experiment. The raw data are presented in two files: one for the natural observations and the second for the experiment. Data were analyzed by R, and R codes were presented.  , , # Does sentinel presence improve foraging success? A study in a cooperative breeder

by Roni Ostreiher, Roger Mundry & Aviad Heifetz

## Files:

* experiment_data.txt and nat_obs_data.txt are tab-separated text files (i.e., plain asci)
* nat_obs_data.txt contains the data collected during the natural observations
* experiment_data.txt contains the data collected during the experiment
* code_natural_observations.r and code_experiment.r contains the R code for the analysis

## Columns in nat\_obs\_data.txt:

* row.id: consecutive integers with row numbers;
* subject: ID of an individual (nested in the group, i.e., the same ID in different group means different individual);
* obs.id.within.group: ID of the trial within a group;
* date: the date at which a trial was conducted [day, month, year; year with 2 or 4 digits];
* foraging_within_sentinel_yes: total time foraging within the shelter when sentinel was present [seconds];
* foraging_within_sentinel_no: total time foraging within the...