Nocturnal vocal behaviour of the diurnal Undulated Tinamou (Crypturellus undulatus) is associated with temperature and moon phase

Abstract

Some diurnal birds vocalize at night but the reason for this has seldom been studied. We monitored the nocturnal vocal activity of the Undulated Tinamou Crypturellus undulatus from June 2015 to May 2016 at three recording stations in the Brazilian Pantanal. We tested whether an index of nocturnal vocal output (number of vocalizations automatically detected) of the species varied over the monitored annual cycle and whether it was related to night temperature and moon phase. The annual pattern of nocturnal vocal output was unimodal, with high vocal activity during September and October (49.9% of the total calls detected) and very low vocal output from January through June (8.5% of the total). The unimodal pattern found suggests that nocturnal vocal activity might be related to mate attraction rather than to territorial defence, for which a more constant pattern would have been expected. The percentage of the moon illuminated was positively associated with nocturnal vocal activity, probably related to the elevated light level on moonlit nights. Nocturnal vocal activity was not associated with minimum air temperature. Nocturnal vocal output was positively associated with vocal output during the preceding night, but not with vocal output during the preceding day, suggesting that it was not directly associated with diurnal calling. This is the first study showing a complete annual cycle of nocturnal vocalizations for a diurnal bird species. Our study provides new evidence regarding the function of and the reasons for nocturnal vocalizations in a diurnal non‐passerine bird and has important implications for continued study of reproductive behaviour in tinamous. Further research should examine whether courtship display is associated with nocturnal vocalizations in this and other species.

Passive Acoustic Monitoring of Chaco Chachalaca (Ortalis canicollis) Over a Year: Vocal Activity Pattern and Monitoring Recommendations

“…The cluster analysis function of Kaleidoscope and the method employed in that study (manually reviewing only the clusters with a high probability of containing a vocalization of Chaco Chachalaca) allowed us to (1) detect the daily presence of the species on 99.7% of the monitored days, (2) detect up to 78% of the calls uttered by the species, and (3) reduce up to 82% the number of candidate sounds to be reviewed. The recognizer employed was able to detect 77.6% of the calls within a recording, which is fully in agreement with four previous studies that monitored seven bird species in the study area applying the same approach (recall rates ranged between 71 and 85%, Pérez-Granados et al, 2021; Pérez-Granados & Schuchmann, 2020a, 2020b, 2021). Those calls detected by the observer but not by Kaleidoscope were likely calls of the Chaco Chachalaca uttered at far distances of the recordings, based on low signal intensity of some of the calls detected in the validation dataset (pers.…”

“…These contradictory results suggest the existence of species-specific differences in diel patterns of vocal activity among cracids. The nocturnal vocal activity of Chaco Chachalaca contributes to the scarce knowledge currently available about the nocturnal vocal activity of diurnal birds (review by La, 2012); however, this type of research has increased in recent years due to the development of autonomous sound recorders (e.g., Celis–Murillo et al, 2016; Foote et al, 2018; Pérez–Granados & Schuchman, 2021).…”

Temporal activity patterns of North China leopards and their prey in response to moonlight and habitat factors

“…On the contrary, the “visual acuity hypothesis” (Huck et al, 2017 ; Pratas‐Santiago et al, 2017 ) states that the brightness of a full moon provides “visually oriented” prey species heightened chance to forage and/or detect danger, with the result that they are expected to be more active during the full moon, showing “lunar philic” activity—in other words preferring brighter moon phases (Fernández Moya et al, 2021 ). For example, brighter nights seem to inhibit the activity of ocelots ( Leopardus pardalis ) (Leonard et al, 2020 ), two‐toed sloth ( Choloepus didactylus ) (De Miranda et al, 2020 ), and red muntjac ( Muntiacus muntjak ) (Rahman & Mardiastuti, 2021 ), while for other species, such as cheetah ( Acinonyx jubatus) (Broekhuis et al, 2014 ), bobcats ( Lynx rufus ) (Leonard et al, 2020 ), Bawean deer (Axis kuhlii ) (Rahman & Mardiastuti, 2021 ), Indian hare (Lepus nigricollis) (Bhatt et al, 2021 ), and some nocturnal birds (Pérez‐Granados & Schuchmann, 2021 ), brighter nights yield increased activity.…”

Diel and seasonal variation of Striped Cuckoo (Tapera naevia) vocalizations revealed using automated signal recognition

“…Amrhein et al . 2002, La 2012, Kułaga & Budka 2020, but see Pérez‐Granados & Schuchmann 2021b); therefore, further research is required to elucidate the functionality of nocturnal vocalizations in the Striped Cuckoo and other cuckoos (Deng et al . 2019, Yoo et al .…”