Wing tags severely impair movement in African Cape Vultures

Abstract

BackgroundThe use of tracking technologies is key for the study of animal movement and pivotal to ecological and conservation research. However, the potential effects of devices attached to animals are sometimes neglected. The impact of tagging not only rises welfare concerns, but can also bias the data collected, causing misinterpretation of the observed behaviour which invalidates the comparability of information across individuals and populations. Patagial (wing) tags have been extensively used as a marking method for visual resightings in endangered vulture species, but their effect on the aerodynamics of the birds and their flight behaviour is yet to be investigated. Using GPS backpack mounted devices, we compared the flight performance of 27 captive and wild Cape Vultures (Gyps coprotheres), marked with either patagial tags or coloured leg bands.ResultsIndividuals equipped with patagial tags were less likely to fly, travelled shorter distances and flew slower compared to individuals equipped with leg bands. These effects were also observed in one individual that recovered its flight performance after replacing its patagial tag by a leg band.ConclusionsAlthough we did not measure the effects of patagial tags on body condition or survival, our study strongly suggests that they have severe adverse effects on vultures’ flight behaviour and emphasises the importance of investigating the effects that tagging methods can have on the behaviour and conservation of the study species, as well as on the quality of the scientific results.

Effect of tag attachment on the flight performance of five raptor species

“…time spent flying). Investigating the effect of harness type on fine-scale flight parameters is also relevant in the context of data standardization and comparability (Curk, T., Scacco, M. et al 2021). The measures of flight performance investigated in our study are commonly used parameters in movement ecology studies focusing on comparing flight behaviour and performance across species, populations or environmental contexts.…”

“…It is therefore of primary importance to investigate how the methodology used to measure these information affects the collected data. Not only to the benefit of the animals’ welfare, but also to avoid systematic bias in our results, which would invalidate data comparability and lead to misinterpreting the behaviour we are trying to measure (Curk, T., Scacco, M. et al 2021, Barron et al 2010).…”

“…Recent studies suggested an adverse effect of bio-logging on several aspects of avian behaviour and ecology (Barron et al 2010), including lower recapture and survival rate, a decreased likelihood of nesting success, nesting productivity and nesting propensity, changes in foraging trip duration, as well as an increase in energy expenditure, predation risk and death (Calvo & Furness 1992, Culik et al 1993, Ballard et al 2001, Zuberogoitia et al 2012, Trefry et al 2013, Vandenabeele et al 2014, Watanuki et al 1992, Miller & Davis 1993, Navarro et al 2008, Taylor et al 2010). Very few studies investigated the effect of the use of bio-logging on flight performance, but some highlighted how birds can reach different flight speeds depending on tag placement (Gessaman & Nagy 1988, Wilson & Culik 1994, Curk, T., Scacco, M. et al 2021). More commonly, studies focus on the effects of device weight relative to the animal’s body mass, the device shape and induced drag depending on the medium in which the animal moves (Vandenabeele et al 2012, Wilson & Culik 1994, Bowlin et al 2010), the device position relative to the centre of mass (Wanless et al 1989, Powell et al 1998, Vandenabeele et al 2014) and the material of the harness used to attach the device (Barron et al 2010, Vandenabeele et al 2013).…”

“…However, other studies did not find neither short-nor long-term differences in reproductive success, survival, activity budget and return rate at the colonies, attributable to the attachment of bio-logging devices Hamel et al (2004), Thaxter et al (2016). Very few studies investigated the effect of the use of bio-logging on flight performance, but some highlighted how birds can reach different flight speeds depending on tag placement (Gessaman & Nagy 1988, Curk, T., Scacco, M. et al 2021. More commonly, studies focus on the effects of device weight relative to the animal's body mass, the device shape and induced drag depending on the medium in which the animal moves (Vandenabeele et al 2012, Bowlin et al 2010, the device position relative to the centre of mass (Wanless et al 1989, Powell et al 1998, Vandenabeele et al 2014) and the material of the harness used to attach the device (Barron et al 2010, Vandenabeele et al 2013.…”

Application of GPS occurrence data to understand African white‐backed vultures Gyps africanus spatial home range overlaps

“…After capture, the vultures were fitted with solar‐charged 3G CTT™ 1000 Series BT3 GPS tracking devices which were harnessed at the back using Teflon ribbons to secure the backpack (Curk et al, 2020; Kendall & Virani, 2012; Pfeiffer et al, 2015; Price‐Rees & Shine, 2011). The capturing and tagging processes were approved and monitored by Zimbabwe Parks and Wildlife Management Authority under Permit No.…”