This study aimed to provide a description on how Pond bats (Myotis dasycneme) disperse, how to recognize a commuting route, and details about the effort needed to make a complete survey of one commuting route. The study area covered the provinces of Zuid-Holland, Overijssel, Friesland, Noord-Holland, and Utrecht. During 6 years of study between 2002 and 2009, researchers and bat volunteers studied pond bats along several waterways (all waterways wider than 10 m) between known roosts and their hunting areas. All the observations were made between April and September, starting 20 min before sunset. During the entire observation effort, the time (in hours and minutes) and direction of each bat was recorded. The time that each bat passed the observation location was later transformed to minutes after sunset. The number of animals on commuting route was related to the number of animals present in their respective roost. Data are organized in 3 files: commuting data 10 minutes.csv, commuting data.csv and observations waddinxveen.csv. The variables in these data files are explained here: Date: the observation date Location description: description of the location X Y: The coordinates of the location in RD. The RD (Rijks-Driehoek) system is the coordinate system used by the Dutch geographical service. Long Lat: The coordinates of the location in longitude and latitude. Distance over water: commuting distance over water. For each route, the distance (d) over water between roost and observation location was measured from a topographical map and expressed in kilometres. Moon cover: the amount of moon cover, expressed in percentages. Roost location: the assumed location of the roost of the bats passing on their commuting route Max N of bats in roost: the max number of bats observed emerging from a roost. Sum N of bats over 10-minute interval: the sum of all the observed bats passing in one direction within a 10-minute interval Time after sunset in 10 min: the begin time of each interval, measured in minutes after sunset Peak time after sunset: the time of the observed peak in numbers of bats, in minutes after sunset. Area: the municipality near the observation location. Total N of pond bats on route: the total number of pond bats observed on route, in the given observation time. Including foraging and returning bats. Total N of commuting pond bats: the total number of bats observed commuting (excluding all other behaviours). Time of first bat minutes after sunset: the time of the first bat, measured in minutes after sunset. Duration of commuting: the time in hours between the first and the last bat observed commuting. Observation time: the total duration (in minutes) of the observation period. Moon phases: a 1–3 scale, where c1 is the new moon, c2 is the first quarter, c3 half moon, c4 is the last quarter and c5 is the full moon. Cloud cover: estimation of the cover, using the following three categories: c1-0%–25% cover (clear night sky or some isolated clouds), c2-25%–75% cover (several scattered clouds but not covering more than 75% of the night sky), and c3- 75%–100% cover (scattered clouds covering more than 75% of the night sky to a completely overcast night sky Observation type: observation of either emerging bats from a roost (roost) or bats observed on commuting route (commuting). In addition, we also provide 2 pdf’s containing the observation protocols (in Dutch) for counting emerging bats (Handleiding tellen van een groep meervleermuizen.pdf) and bats along a commuting route (Handleiding vliegroute telling.pdf). The protocols are intended for professionals and citizen scientists.

{"references": ["Haarsma, A. J., & Siepel, H. (2013). Group size and dispersal ploys: an analysis of commuting behaviour of the pond bat (Myotis dasycneme). Canadian Journal of Zoology, 92(1), 57-65."]}