Data from: The effects of age on vocal mimicry in female superb lyrebirds

The study of vocal mimicry in birds has been largely dominated by
male-focused sexual selection theory. Despite this, females of many
species demonstrate remarkable mimetic abilities that cannot be explained
by these conventional male-centric frameworks. We analysed vocal
recordings from nesting female superb lyrebirds (Menura novaehollandiae)
to examine age-related patterns in mimetic behaviour during a female
specific ecological context: nest defence. Our dataset includes
annotations from the 10-minute recordings from individual females of known
age, with a subset of six females recorded across multiple years. We
classified vocal elements into three categories: mimicry of heterospecific
sounds, conspecific vocalisations, and ambiguous elements which were
assumed to be mimicry production errors. For mimetic elements, we
identified the model species and sound type and categorised models as
predators versus non-predators. We constructed repertoire accumulation
curves to validate our 10-minute sampling protocol. We used linear mixed
models (LMM) and generalised linear mixed models (GLMM) to analyse
relationships between female age and various aspects of vocal behaviour,
including total element production, mimetic diversity, time spent
vocalising, and predator mimicry proportions. Additional analyses examined
potential confounding factors including testing for habituation and the
effects of time of breeding. Our data reveals high individual variation in
mimetic behaviour, with no age effects on overall mimicry propensity or
diversity. However, older females are more likely to mimic predators
during nest defence than younger females.  There are two main
implications of these findings. First, age-related factors are unlikely to
account for individual variation in female mimetic repertoires. Second,
females may refine their vocal mimicry with age, selectively retaining
models that offer the greatest defensive advantage during nest defence.