Loss of vocal culture and fitness costs in a critically endangered songbird

Cultures in humans and other species are maintained through interactions among conspecifics. Declines in population density could be exacerbated by culture loss, thereby linking culture to conservation. We combined historical recordings, citizen science and breeding data to assess the impact of severe population decline on song culture, song complexity and individual fitness in critically endangered regent honeyeaters (Anthochaera phrygia). Song production in remaining wild males varied dramatically, with 27 % singing songs that differed from the regional cultural norm. Occurring at low population density 12% of males completely failed to sing any species-specific songs and instead sang other species’ songs. Atypical song production was associated with reduced individual fitness, as males singing atypical songs were less likely to pair and nest than males that sang the regional cultural norm. Songs of captive-bred birds differed from those of all wild birds. The complexity of regent hon..., (a) Data collection
We used data from all regent honeyeater sightings throughout the species’ range from July 2015 to December 2019 to estimate the distribution and density of the remaining wild population. Regent honeyeaters can be sexed in the field based on a combination of their size, plumage traits, behaviour, vocal attributes and in the hand during marking with unique combinations of coloured leg bands25. The database consisted of confirmed public sightings reported to BirdLife Australia and data from a standardized national monitoring program based on 1367 sites throughout the breeding range25. We identified males individually through a combination of colour bands on the focal male or partner female (n = 93), nest location (n = 68), unique song attributes (n = 21) or a lack of other males nearby (n = 42)25. We recorded males’ songs using a Sennheiser ME62/K6 microphone on a Telinga parabola and a Marantz PMD661 digital handheld recorder. We recorded captive-bred birds either shor..., The dataset contains X files:

\"Recordings_summary.xlsx\" = full details of each male regent honeyeater, where, when and how it was recorded, whether that male was observed and or recorded in multiple years, which analysis each male could be included in and which sound file(s) correspond to which male. We have withheld sensitive location data (lat,long) because (i) of the critically endangered population status of the species and (ii) it is not required to replicate the data analysis with the files available here. Specific location data is available from the corresponding author upon reasonable written request.
\"Recordings for manuscript analysis.zip\"  = .wav regent honeyeater song sound files used in the manuscript.
\"Repeat recordings.zip\" = .wav regent honeyeater song sound files, including repeat files of some males where available, for use in modelling song repeatability.
\"Regent honeyeater song script.R\" 
\"paired1.csv\" = for re-running GLM of pairing status of males by song type and...