50 years of bat tracking: device attachment and future directions

Abstract

Summary1. Radiotelemetry and satellite-based telemetry approaches are essential to describe the behaviour and biology of animals. This is especially true for bats, whose small size and cryptic lifestyles make them challenging to study. However, only a handful of studies have evaluated how transmitter mass and the attachment method affect bat behaviour or health, and none have assessed the development of technical methods in the field. 2. We review the past 50 years of bat tracking studies to determine how devices have been attached, how guidelines have been followed or changed, and whether any health or fitness impacts from these transmitters can be determined. 3. Half of the nearly 300 studies available used devices heavier than the recommended 5% of body mass with minimal justification. Devices were typically glued directly to the backs of small bats and remained attached for 9 days. This is far shorter than battery life span of most devices. Little information is available regarding the overall impact of attaching transmitters on the health, survival and reproductive success of bats, and there has been little development in attachment methods since the first tracking studies. 4. We consequently developed a collar for small bats with a degradable weak link and tested it on several species. The collar worked successfully on three of four species. This allows longer habituation and tracking times while ensuring that the device drops off after the battery expires. 5. Future studies will need to invest more effort in assessing potential long-term effects of tracking. They also need to build upon previous knowledge to find the best attachment method, size and shape for their study species to effectively improve wildlife tracking.

High-resolution GPS tracking of Lyle's flying fox between temples and orchards in central Thailand

“…At WP, we used GPS loggers fitted with different batteries (Primary III) with a mass of 25.5 g, accounting for 4.3-6.1% of the body mass (mean body mass AE SD: 533.6 AE 60.5 g, n ¼ 11). This slightly exceeded 5% of the body mass in 2 tracked bats but remained below 10%, which is considered as maximum threshold in bats weighing more than 70 g in several studies (O'Mara et al 2014). We glued most loggers (n ¼ 23) between the scapulae with skin adhesive (Manfred Sauer GmbH, Lobbach, Germany) after trimming the dorsal fur, followed by a second layer of instant glue.…”

“…The last batch of loggers (n ¼ 9) was first superglued and then sewed on to T-shaped pieces of leather. We then tied these leather collars around the bats' neck with surgical thread (Safil C, B. Braun Petzold GmbH, Melsungen, Germany) that decomposes after about 1 month (O'Mara et al 2014). All bats were hand fed with mangoes or bananas at the end of the handling procedure and subsequently released.…”

Short-term effects of tagging on activity and movement patterns of Eurasian beavers (Castor fiber)

“…Kissling et al 2014;O'Mara et al 2014) and reduced perceived impact on tagged animals in general (Golabek et al 2008;Ropert-Coudert et al 2009). Yet, the capture and tagging procedure can be stressful for the animal (Fletcher and Boonstra 2006;Lapointe et al 2015) and trigger physical and psychological effects, which can alter the animals' behaviour (Saraux et al 2011;Wilson 2011).…”

Telemetry for migratory bats : a feasibility study

“…Because of the body weight of our main species of interest, Nathusius' pipistrelle, we can only apply radio (VHF) transmitter tags to follow their movements, as other devices will exceed the 5%-weight threshold (Aldridge & Brigham 1988, O'Mara et al 2014). …”