Many animals produce coordinated signals, but few are more striking than the elaborate male-female vocal duets produced by some tropical songbirds. Yet, little is known about the factors driving the extreme levels of vocal coordination between mated pairs in these taxa. We examined evolutionary patterns of duet coordination and their potential evolutionary drivers in Neotropical wrens (Troglodytidae), a songbird family well-known for highly coordinated duets. Across 23 wren species we show that the degree of coordination and precision with which pairs combine their songs into duets varies by species. This includes some species that alternate their song phrases with exceptional coordination to produce rapidly alternating duets that are highly consistent across renditions. These highly coordinated, consistent duets evolved independently in multiple wren species. Duet coordination and consistency are greatest in species with especially long breeding seasons, but neither duet coordination nor consistency are correlated with clutch size, conspecific abundance, or vegetation density. These results suggest that tightly coordinated duets play an important role in mediating breeding behaviour, possibly by signalling commitment or coalition of the pair to mates and other conspecifics.

The "Neotropical Wren selections compiled & renamed FINAL - ForDryad.csv" consists of start and end times for all male and female notes within duets for 23 Neotropical wren species. These were extracted from the bounding boxes surrounding each selected note in Raven Sound Analysis Software v1.5.  Start-end measurements were collected for a random sample of approximately 10 duets from 1-6 pairs of wrens per species. These data can be processed to create coordination scores for each song in the dataset using code provided in the supplementary data of the associated manuscript.

The "Neotropical Wren_AllSong&NatHistData_ForDryad.csv" was created from the averaged values of the coordination scores for each species and combined with natural history data for each each species, including breeding season length and clutch size (taken from Handbook of the Birds of the World), an estimate of species prevalence (estimated from eBird data), and vegetation density (calculated from Enhanced Vegetation Index (EVI) data extracted from NASA MODIS satellite (product: MOD12A3 v6)).