Roosting behaviour and phenology of the Lesser horseshoe bat (Rhinolophus hipposideros) in a breeding colony in Sintra, Portugal

Abstract

Almost all bats are exclusively nocturnal. However, the activity patterns throughout the night can differ between species and also within the same species from place to place. Rhinolophus hipposideros (Bechstein, 1800) has suffered a severe decline in many countries along its distribution area, including Portugal. In this study we aimed to describe the roosting behaviour during spring, summer and autumn of one of the largest maternity colonies of R. hipposideros known in Portugal. We analysed roost occupancy, activity patterns inside the roost, birth periods, and post-natal behaviour. We also tested the influence of ambient factors on the patterns of roost use. All information was obtained through the analyses of video recorded using cameras placed inside the roost, while climatic data were gathered using a meteorological station. We found that this roost has higher occupation during August and that in October it is only occupied during the night. Females gave birth from late May to early June, and in August juveniles became independent and undistinguishable from the adults. This colony presented a bimodal pattern of activity throughout the months of the study, which seems to be related with sunset and sunrise. Our results indicate that individuals of this colony prefer higher temperatures, but low humidity and wind speed to leave the roost. Key Words: Rhinolophus hipposideros, paternal care, roost use, Portugal. ResumenCasi todos los murciélagos tienen hábitos nocturnos pero los patrones de actividad durante la noche pueden variar entre las especies y dentro de la misma especie en diferentes lugares. El murciélago pequeño de herradura Rhinolophus hipposideros (Bechstein, 1800) sufrió un severo declive en muchos países de su área de distribución, incluyendo Portugal. En este estudio, se pretende describir el comportamiento de refugio durante la primavera, verano y otoño de una de las colonias de cría más grande de R. hipposideros en Portugal. Asimismo, se analizó la ocupación y los patrones de actividad en el refugio, el periodo de nacimientos, y el comportamiento postnatal. También se comprobó el efecto de los factores ambientales en el uso del refugio. Toda la información se obtuvo a partir del análisis de los videos grabados en el interior del refugio. Los datos climáticos se obtuvieron mediante una estación meteorológica. Se observó que el refugio tiene una mayor ocupación durante el mes de agosto y que en octubre sólo se ocupa durante la noche. Las hembras dan a luz entre finales de mayo y principios de junio, y en agosto los juveniles parecen ser independientes e indistinguibles de los adultos. Esta colonia presenta un patrón bimodal de actividad que parece estar relacionado con el atardecer y amanecer. Nuestros resultados también indican que esta colonia de murciélagos prefiere altas temperaturas pero baja humedad y una cierta velocidad del viento para abandonar el refugio. Palabras clave: Rhinolophus hipposideros; cuidado paternal; uso de abrigo; Portugal. Galemys 27, 2015 2

Usage of buildings in the life cycle of two endangered Rhinolophus species in the Mediterranean region: implications for roost protection

“…However, all nurseries provided secured entrances which may constitute a crucial factor for the survival of the non-fledged juveniles left behind in the nursery during the night. Across nurseries, higher temperatures correlated with an earlier onset of parturition, confirming previous findings in various geographic regions (e.g., Schofield 1996;Zahn 1999;Lino et al 2015). Moreover, we found a higher proportion of reproductive females in warmer nurseries.…”

“…Thus, in the present study, roost switching was either conducted by males, which have a higher affinity to change roosts (compare Downs et al 2016), or by non-reproductive females. In contrast, studies from Central Europe showed roost switching of females with their pups, caused by changes in temperatures that where either too low (Kolb 1950;Lino et al 2015) or too high (Kayikcioglu and Zahn 2004). This discrepancy may be accounted for by two facts: in our study, the temperature of 34°C given in Kayikcioglu and Zahn (2004) was never exceeded in all parts of a given nursery so that bats could move to alternative perching sites (compare e.g.…”

“…They always showed an initial foraging bout after dusk and a last foraging bout before dawn. This may reflect an adaptation to peaks in prey abundance (Swift 1980;Rautenbach et al 1988;Jones and Rydell 1994;Lino et al 2015) which reproductive females will rely on to satisfy their energy budget during lactation. In total, mothers left the roost during about 50% of the night, which fits to studies from Central Europe (Kurta et al 1989;Zahn et al 2008).…”

Time-lapse photography as an effective method for bat population monitoring

“…Recent advances in technology have enabled scientists to address important questions about the social life and phenology of bats (Sedgeley 2012a, Rydell & Russo 2015, Lino et al 2015. Remote camera traps are a non-invasive method that can outperform traditional methods of visual counts and provide valuable information on the social behavior, phenology, daily movements and activity cycle of bats (Sedgeley 2012b, Lino et al 2015). The present paper provides data about a non-intrusive and novel method to monitor bat populations using time lapse cameras (Rydell & Russo 2015).…”

“…The first juveniles appeared in the small and hotter room, indicating that temperature might play an important role in the timing of reproduction (Lucan et al 2013). This species positively selects warm roosts during the lactation period (Schofield 1996, Lino et al 2015, which may be the reason why they first gave birth in the small room. Later, during the season when temperatures were similar between the two rooms, females also gave birth in the larger room.…”