Studying Wild Bats with Small On-Board Sound and Movement Recorders

Post provided by LAURA STIDSHOLT

Releasing a female Greater mouse-eared bat with the tag in collaboration with Holger Goerlitz, Stefan Greif and Yossi Yovel. ©Stefan Greif

The way that bats acrobatically navigate and forage in complete darkness has grasped the interest of scientists since the 18th century. These seemingly exotic animals make up one in four mammalian species and play important roles in many ecosystems across the globe from rainforests to deserts. Yet, their elusive ways continue to fascinate and frighten people even today. Over the last 200 years, dedicated scientists have worked to uncover how bats hunt and navigate using only their voice and ears while flying at high speed in complete darkness. Still, the inaccessible lifestyle of these small, nocturnal fliers continues to challenge what we know about their activities in the wild.

Understanding the impact bats have on their ecosystems – for example how many insects a bat catches per night – has still not been directly measured. Most of our knowledge on the natural behaviour and foraging ecology is based on elaborate, but ground-based experiments carried out in the wild. These experiments generally track their behaviour using radio-telemetry, record snapshots of their emitted echolocation calls with microphones, or involve extensive observations. Continue reading

Movement Ecology: Stepping into the Mainstream

Post provided by Theoni Photopoulou

“Movement is the glue that ties ecological processes together”
from Francesca Cagnacci et al. 2010

CTD-SRDL telemetry tags being primed for deployment. ©Theoni Photopoulou

CTD-SRDL telemetry tags being primed for deployment. ©Theoni Photopoulou

Movement ecology is a cross-disciplinary field. Its main aim is to quantitatively describe and understand how movement relates to individual and population-level processes for resource acquisition and, ultimately, survival. Today the study of movement ecology hinges on two 21st century advances:

  1. Animal-borne devices/tags (biologging science, Hooker et al., 2007) and/or remote sensing technology to quantify movement and collect data from remote or otherwise challenging environments
  2. Computational power sufficient to manipulate, process and analyse substantial volumes of data

Although datasets often involve small numbers of individuals, each individual can have thousands – sometimes even millions – of data points associated with it. Study species have tended to be large birds and mammals, due to the ease of tag attachment. However, the trend for miniaturisation of tags and the development of remote detection technologies (such as radar, e.g. Capaldi et al., 2000), have allowed researchers to track and study ever smaller animals. Continue reading