Implantation reduces the negative effects of bio-logging devices on birds

Abstract

SUMMARYAnimal-borne logging or telemetry devices are widely used for measurements of physiological and movement data from free-living animals. For such measurements to be relevant, however, it is essential that the devices themselves do not affect the data of interest. A recent meta-analysis reported an overall negative effect of these devices on the birds that bear them, i.e. on nesting productivity, clutch size, nest initiation date, offspring quality, body condition, flying ability, foraging behaviours, energy expenditure and survival rate. Method of attachment (harness, collar, glue, anchor, implant, breast-mounted or tailmount) had no influence on the strength of these effects but anchored and implanted transmitters had the highest reported rates of device-induced mortality. Furthermore, external devices, but not internal devices, caused an increase in ʻdevice-induced behaviourʼ (comfort behaviours such as preening, fluffing and stretching, and unrest activities including unquantifiable ʻactiveʼ behaviours). These findings suggest that, with the exception of device-induced behaviour, external attachment is preferable to implantation. In the present study we undertake a metaanalysis of 183 estimates of device impact from 39 studies of 36 species of bird designed to explicitly compare the effects of externally attached and surgically implanted devices on a range of traits, including condition, energy expenditure and reproduction. In contrast to a previous study, we demonstrate that externally attached devices have a consistent detrimental effect (i.e. negative influences on body condition, reproduction, metabolism and survival), whereas implanted devices have no consistent effect. We also show that the magnitude of the negative effect of externally attached devices decreases with time. We therefore conclude that device implantation is preferable to external attachment, providing that the risk of mortality associated with the anaesthesia and surgery required for implantation can be mitigated. We recommend that studies employing external devices use devices that can be borne for long periods, and, wherever possible, deploy devices in advance of the time period of interest. Supplementary material available online at

Evidence that dorsally mounted satellite transmitters affect migration chronology of Northern Pintails

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“…As their use has become more common, the effects of transmitters and data loggers on avian species have been increasingly scrutinized (e.g., Barron et al 2010; Vandenabeele et al 2011;White et al 2013). However, relatively few studies have examined whether attachment of satellite transmitters or other tracking devices can affect the timing of avian migration.…”

An increase in minimum metabolic rate and not activity explains field metabolic rate changes in a breeding seabird

“…The gannets were selected randomly in September of the 2004-2005 breeding period while incubating their eggs, and all six apparently bred normally (Green et al, 2009c), suggesting that, as in previous studies, the birds were not negatively affected by the presence of the DL (White et al, 2013). We have previously used this data set to describe activity-specific f H and diving behaviour and physiology of this species.…”

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

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