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

Abstract

Research on the songbird zebra finch (Taeniopygia guttata) has advanced our behavioral, hormonal, neuronal, and genetic understanding of vocal learning. However, little is known about the impact of typical experimental manipulations on the welfare of these birds. Here we explore whether the undirected singing rate can be used as an indicator of welfare. We tested this idea by performing a post hoc analysis of singing behavior in isolated male zebra finches subjected to interactive white noise, to surgery, or to tethering. We find that the latter two experimental manipulations transiently but reliably decreased singing rates. By contraposition, we infer that a high-sustained singing rate is suggestive of successful coping or improved welfare in these experiments. Our analysis across more than 300 days of song data suggests that a singing rate above a threshold of several hundred song motifs per day implies an absence of an acute stressor or a successful coping with stress. Because singing rate can be measured in a completely automatic fashion, its observation can help to reduce experimenter bias in welfare monitoring. Because singing rate measurements are non-invasive, we expect this study to contribute to the refinement of the current welfare monitoring tools in zebra finches.

Goal-directed vocal planning in a songbird

“…We calculated pitch (fundamental frequency) as described in ( 14 ). To provide pitch reinforcement in real time, we used a two-layer neural network trained to detect a manually clustered syllable containing a harmonic stack ( 44 ). We evaluated the fundamental frequency of that syllable in a 16-24-ms time window following detection.…”

Birdsong and the Neural Regulation of Positive Emotion

“…It has been proposed that song in gregarious contexts can be considered a form of rewarding play behavior similar to forms of play observed in multiple young animals as they practice sequences of motor events that are used later in adult reproductive contexts ( Thorpe, 1956 ; Hartshorne, 1973 ; Ficken, 1977 ; Fagen, 1981 ; Burghardt, 2005 ; Riters et al, 2017 ). Performing behaviors for “amusement” (i.e., because they induce a positive emotional state) essentially defines play, and similar to other forms of playful behavior, gregarious song is facilitated by reunion with social partners, and it is initiated when an animal is fed, healthy and free from stress (e.g., in the absence of predators) ( Panksepp and Beatty, 1980 ; Burghardt, 2005 ; Siviy et al, 2006 ; Yamahachi et al, 2020 ; Kim et al, 2021 ). This suggests that like other forms of play behavior, safety and the presence of flock mates may induce a positive emotional state that is conducive to singing, which may then be maintained by reward induced by the act of singing itself.…”

TweetyNet: A neural network that enables high-throughput, automated annotation of birdsong

“…1 and 2, necessitating the development of an algorithm like the one we present. However, for birdsong that consists largely of a single fixed motif, like that of zebra finches, several methods have been widely used, including semi-automatic clustering methods [21,22], and template matching [23][24][25]. Several studies have also applied supervised learning algorithms to annotation, such as Hidden Markov Models [26], k-Nearest Neighbors [27], and support vector machines [28].…”