The Animal Locator: a new method for accurate and fast collection of animal locations for visible species

Abstract

Ranging behaviour is one of the most important aspects of the life history of many species. Spatial distributions of individuals in the wild is linked to factors such as foraging, mating, population density, availability of resources and competition. Accurate data on the spatial location of individuals over time is often difficult to collect. Here, we propose a new simple, non‐invasive and economic method for collecting accurate spatial data usable for many different species of free‐ranging animals. Our instrument for collecting animal locations consists of three elements: a laser range finder, a laser tilt sensor and a protractor. This instrument can obtain three‐dimensional parameters of the space from a fixed point allowing the user to collect geographical locations of the animals and, in general, of any point of interest. The device we tested showed a very low average error among (1.76 ± 0.643 m) and within (1.79 ± 0.058 m) observers, and the locations we obtained were all within the 95% probability of the tolerance intervals for the 20 positions which we measured repeatedly with a Global Position System for each of 10 different test locations. We tested a range of different distances to the target points (from 20 to 222 m), and we propose formulas to calculate precision of the instrument inside this interval. Precision of estimated locations was between 0.32 to 3.55 m from the real location and it was slightly related to distance of the target point (r = 0.38, P = 0.054). As an example of its practical application, we present data on the use of the instrument within the framework of a study on a population of free‐ranging individually tagged alpine marmots Marmota marmota.

Helpers influence on territory use and maintenance in Alpine marmot groups

“…Male sex-6 bias at weaning has been reported in Alpine marmots (Allainé 2000) and females born in a malebiased litter show a higher probability of becoming dominant in the future (Hackländer & Arnold 2012). Alpine marmots are diurnal and the groups occupy relatively small and stable territories (Perrin et al 1993b;Pasquaretta et al 2012). They are, therefore, easy to observe.…”

Social network analysis of small social groups: Application of a hurdle GLMM approach in the Alpine marmot (Marmota marmota)

“…Individuals were generally not visible for the entire scan, as they spend time below ground or could be out of sight. Therefore, some missing observations are present, but with a low frequency for above‐ground behaviors, as a large majority of the home range (we estimate a 70%–90% of it in each family) was generally visible from the observation point (Pasquaretta et al., 2012).…”

“…Dominants reproduce almost exclusively (Barash, 1976; Cohas et al., 2007) and helpers delay dispersal to increase pups' survival (Allainé & Theuriau, 2004) and help with territory defense (Pasquaretta et al., 2015). The territory of an Alpine marmot group is relatively small and stable (Pasquaretta et al., 2012), thus they are easy to observe. A social group shares the same burrow system in which they hibernate socially during winter (Zelenka, 1965); burrows are also used overnight and to escape from predators (Ferrari et al., 2010).…”

Extrinsic and intrinsic factors affecting the activity budget of alpine marmots (Marmota marmota)

“…By being diurnal and territorial, and thus easily observable when above ground, scan sampling is a suitable method to collect behavioural data on this species. Scan sampling was conducted 5 days per week alternating among the different family groups by using long-view scopes (Swarovski 30x75 and Nikon ED82 25-56X82) following the method described in Pasquaretta et al (2012Pasquaretta et al ( , 2015. Scan sampling sessions, lasting 1 h each, were conducted for the whole day from 07:00 to 20:00 (Central European Summer time), with a break between 13:00 and 14:00 for the entire time of this study.…”