Welfare of zebra finches used in research

Abstract

Over the past 50 years, songbirds have become a valuable model organism for scientists studying vocal communication from its behavioral, hormonal, neuronal, and genetic perspectives. Many advances in our understanding of vocal learning result from research using the zebra finch, a close-ended vocal learner. We review some of the manipulations used in zebra finch research, such as isolate housing, transient/irreversible impairment of hearing/vocal organs, implantation of small devices for chronic electrophysiology, head fixation for imaging, aversive song conditioning using sound playback, and mounting of miniature backpacks for behavioral monitoring. We highlight the use of these manipulations in scientific research, and estimate their impact on animal welfare, based on the literature and on data from our past and ongoing work. The assessment of harm-benefits tradeoffs is a legal prerequisite for animal research in Switzerland. We conclude that a diverse set of known stressors reliably lead to suppressed singing rate, and that by contraposition, increased singing rate may be a useful indicator of welfare. We hope that our study can contribute to answering some of the most burning questions about zebra finch welfare in research on vocal behaviors. Therefore, the interplay between corticosterone levels during development and long-term consequences of stress needs to be further studied. Skin temperatureA stressor can increase the core body temperature, provoking a decrease of the surface temperature. This phenomenon known as stress-induced hyperthermia could be utilized to measure stress. Indeed, infrared thermography has been used to determine the effect of stressful procedures in birds (Edgar et al., 2013;Herborn et al., 2015;Jerem et al., 2015) . Contrary to the stress snapshot of corticosterone, this non-invasive imaging method might provide longitudinal measurements of stress. Body weightBody weight can be used to assess body condition in birds, especially when multiple measurements are made over the course of a study (Brown, 1996;Dickens et al., 2009bDickens et al., , 2009a .

Undirected singing rate as a non-invasive tool for welfare monitoring in isolated male zebra finches

“…We analyzed the singing rate (number of daily song motifs, unless specified) by focusing particularly on its stability and suitability for serving as a baseline against which to compare the effects of experimental manipulations. All data analyzed stemmed from earlier experiments—some of which are published [ 35 , 36 ]—aimed either at probing the plasticity of song syllables in terms of their pitch/duration or at studying/manipulating neuronal activity. The goals of these experiments and the planned/performed analyses were not linked with either welfare or singing rate as a behavioral readout.…”

“…We evaluated the effects of a variety of experimental manipulations on the undirected singing rate in male zebra finches. We performed a post hoc analysis of more than three million song motifs (stereotyped sequences of 3-7 syllables) from our ongoing and published work [35,36]. Because isolation is usually a required condition to carry out well-controlled vocal learning experiments, all our analyses were carried out in isolated birds.…”

Cascading Effects of Conspecific Aggression on Oxidative Status and Telomere Length in Zebra Finches

“…Their immediate social environment is thus composed of their sexual partner and their chicks. However, they regularly interact with other flock members when competing for food resources, mates, or materials for nest building (Evans 1970;Zann 1996;Yamahachi et al 2017). This competition can result in aggressive social behavior between conspecifics (Evans 1970;Caryl 1975;Bonoan et al 2013).…”