Mapping an elusive arboreal rodent: Combining nocturnal acoustic surveys and citizen science data extends the known distribution of the edible dormouse (Glis glis) in the Czech Republic

Main functions of loud vocalization in populations of edible dormouse Glis glis

The study aimed to determine when, during summer activity, males and females of the edible dormouse most often used loud calls. On this basis, an attempt was made to determine the main purpose of the emission of these calls. It was assumed that 1) if males have the most of loud calls in July, their emissions may be related primarily to the mating behaviour (which takes place during this period), and if they have the most of loud calls in August, their emissions are most likely concerned defence of food resources, 2) in females, most of this vocalization would occur in August due to the need to defend their food resources and 3) in both sexes, more vocalization would occur in the year of good beech fruit crop (when the dormice would reproduce) than in the year of no crop (when the dormice would not reproduce). To check these assumptions, the number of loud calls and “performances” (series of loud calls) emitted by the animals from two wild populations tracked by telemetry was noted. The mean number of “performances” and loud calls in males and females was higher in August than in July (when beech fruits ripen), but significant differences were found only for “performances”. Both males and females had significantly more “performances” and loud calls in the mast/breeding year than in the non-mast/non-breeding year. It seems that males and females use loud calls mainly to defend important resources and are, therefore, most often heard during the mast year.

Circadian activity of the fat dormouse Glis glis measured with camera traps at bait stations

Monitoring of small nocturnal and arboreal rodents is difficult and often conducted using indirect techniques. Here, we measured the circadian activity of the fat dormouse (Glis glis) directly using camera traps. The study took place at the Spitzberg in SW Germany. Data were collected using six Bushnell Natureview cameras with a macro lens at baited feeding stations. At 14 out of 41 active camera locations, edible dormice occurred. We collected 301 events between 8th July and 5th October 2018. There were 21.5 events per camera trap (SD 30.4), ranging from 1 to 82. The edible dormouse showed a nocturnal pattern, with a mean activity around midnight at 24:15 h. The pattern shows a slightly bimodal activity. Feeding activity started around or even slightly before sunset and stopped right before sunrise. The study shows that circadian activity, in this respect feeding activity, can be captured by camera trapping, which is a non-invasive method, and can be applied easily in the field.

Community-based population monitoring for large baleen whales: the case study of Bryde's whale in Beibu Gulf of China

Citizen science is a popular method for the long-term monitoring of the distribution of wild animals. The application of these methods in different species and environments still poses challenges, especially for aquatic animals. In this study, we investigated the distribution of the Bryde's whale (Balaenoptera edeni) in the Beibu Gulf of China by using scientific boat-based surveys and citizen science approaches using 2 different methods of data collection. First, we built our mobile app (Whale Guard) and installed it on fishermen's phones. Second, we used a popular instant messaging app (WeChat) to create an online fisherman community. We found that the mobile phone app collected far fewer reports (5 reports) than the online community group (42 reports, P < 0.01). By using a variety of incentives, we maintained the fisherman's community's activity without significant user loss (P < 0.01). We also found that the locations collected by social media applications in this study were consistent with observations from scientific boat-based transect surveys. The sightings distribution of Bryde's whales differed from those in previous surveys in that they were present across larger areas. Social media apps reported that 69% of reports was confirmed by more than one person, whereas Whale Guard reports were much lower (0, P <0.001). Community-based citizen science can greatly contribute to the long-term monitoring of Bryde's whales, and it has successfully overcome the challenges of data accessibility, accuracy, and fragmentation. Our study shows how to appropriately use citizen science in different community groups and community-based approaches make them useful for large baleen whale surveys.