title: Vocal exchanges during pair formation and maintenance in the zebra finch (Taeniopygia guttata).
abstract: BACKGROUND
  Pair compatibility affects the success of a pair; however, its causes and mechanisms are not fully understood. Vocal exchange may be very important for pair formation, coordinating pair activities, maintaining the pair bond and mate guarding. To investigate the role of vocal exchange in pair formation and pair maintenance, we explored whether new and established pairs of zebra finches differed in their calling relationships. We used individualised backpack microphones to examine the entire daily vocal emission of pairs, with parallel video recording of behaviour.
  
  
  RESULTS
  We found that in non-breeding, isolated pairs, a specific type of call, the "stack call", was the most common. Furthermore, all pairs used the stack call for precisely timed antiphonal exchange. We confirmed a difference between new and established pairs in social behaviour, with the former spending less time in physical contact. Notably, we found that this was mirrored by a difference in calling behaviour: members of new pairs converged over time on a more symmetric calling relationship. Additionally, we observed different response rates to partners among individuals, but a repeatable relationship of answering within pairs, which may reflect different degrees of motivation to answer the partner.
  
  
  CONCLUSIONS
  Our findings show that there is plasticity in calling behaviour and that it changes during pair formation, resulting in a coordinated stack call exchange with a similar number of answers between partners once the pair is established. It is possible that some of the calling relationship measurements that we present reflect pair compatibility.
authors.affiliation: Department Gahr - Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany.
authors.forename: Pietro Bruno
authors.initials: PB
authors.lastname: D'Amelio
authors.affiliation: Department Gahr - Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Trost
authors.affiliation: Department Gahr - Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany.
authors.forename: Andries
authors.initials: A
authors.lastname: Ter Maat
keywords: Antiphonal calling; Individualized recording; Monogamous songbirds; Pair compatibility; Vocal communication