2.2 | Location and life history data
Location data are collected during annual systematic surveys conducted
between the months of July–September. Each day (weather permitting) one
of seven sections is surveyed on foot by one or multiple observers, and
adjacent sections are not surveyed on consecutive days. Consequently,
each section is typically surveyed once per week over a 6 to 8 weeks
period. When horses are encountered, identifying photos are taken
alongside location to the nearest 5 m using a handheld GPS device. Every
year, each horse is sighted 5 ± 2 times (\(\overset{\overline{}}{x}\) ±
SD; Rozen-Rechels et al., 2015). Annual surveys across years allow us to
track the birth, age, change in reproductive status, death, and social
parentage of every individual.