Singing behaviour of ruby‐crowned kinglets Regulus calendula in relation to time‐of‐day, time‐of‐year and social context

Abstract

Observational field studies provide insight on the multifunctional nature of birdsong. For example, if song production were limited to pre‐fertilization, then that would suggest a mate attraction function. If it were used throughout the breeding season and in response to intruding males, then that would suggest a territorial defence function. In the present study, we determined the daily and seasonal singing patterns of male ruby‐crowned kinglets Regulus calendula in Labrador, Canada, using microphone arrays in two breeding seasons. Using a playback experiment, we simulated a territorial intrusion to compare the structure of songs produced while defending a territory to the structure of songs produced during solo and contest singing. Singing peaked in the early part of the breeding season and then declined continuously for the remainder of the season, which suggests that the songs function in mate attraction. Singing peaked 2–3 h after dawn, and then declined steadily until it stopped at 10 pm. Some nocturnal singing was observed, but no dawn singing was observed. A high probability of signal overlap by heterospecific songs at dawn would hinder signal recognition and explain the observed delay in peak singing activity. Vocal responses to playback suggested a function in territory defence. However, there were no significant differences in the duty cycle, frequency modulation and bandwidth of songs in relation to the context of song production, though songs were shorter in the intrusion context than during solo singing. Overall, the study provides the first quantitative description of the effects of time of day, time of year and social context on singing behaviour in this understudied species.

Relationships of song structure to phylogenetic history, habitat, and morphology in the vireos, greenlets, and allies (Passeriformes: Vireonidae)

“…Minimum and maximum peak frequency were the 5th and 95th percentiles, respectively, of all peak frequency values from all 2-ms time bins within a song (excluding silent periods between elements). We used the 5th and 95th percentiles, rather than the minimum and maximum values, because they are less likely to be artifacts or outliers that misrepresent the acoustic space used by a given species (Podos et al 2016;Fahmy and Wilson 2020). Finally, we calculated frequency modulation as the cumulative absolute change in peak frequency between all consecutive 2-ms time bins (excluding silent periods between elements), divided by the cumulative duration of all elements.…”

The relationships of breeding stage to daytime singing behaviour and song perch height in Bermuda white‐eyed vireosVireo griseus bermudianus

“…Temporal components of song also vary. Song rate, for example, varies seasonally and throughout the day (Avey et al 2011, Odom et al 2016, Fahmy and Wilson 2020), and these patterns can differ for migratory species that sing primarily on their temperate breeding grounds (Emlen 1973) and Neotropical species that sing year‐round (Demko and Mennill 2018). Although song research has traditionally focused on males (Rose et al 2022), female song is prevalent in many species and is likely the ancestral state (Riebel et al 2019).…”