Previously unknown behavior in parasitic cuckoo females: male-like vocalization during migratory activity

Swetlana G Meshcheryagina,Alexey Opaev

doi:10.1186/s40657-021-00246-9

Abstract

BackgroundIn the last decade, enigmatic male-like cuckoo calls have been reported several times in East Asia. These calls exhibited a combination of vocal traits of both Oriental Cuckoo (Cuculus optatus) and Common Cuckoo (Cuculus canorus) advertising calls, and some authors therefore suggested that the enigmatic calls were produced by either Common × Oriental Cuckoo male hybrids or Common Cuckoo males having a gene mutation. However, the exact identity of calling birds are still unknown.MethodsWe recorded previously unknown male-like calls from three captive Oriental Cuckoo females, and compared these calls with enigmatic vocalizations recorded in the wild as well as with advertising vocalizations of Common and Oriental Cuckoo males. To achieve this, we measured calls automatically. Besides, we video-recorded captive female emitting male-like calls, and compared these recordings with the YouTube recordings of calling males of both Common and Oriental Cuckoos to get insight into the mechanism of call production.ResultsThe analysis showed that female male-like calls recorded in captivity were similar to enigmatic calls recorded in the wild. Therefore, Oriental Cuckoo females might produce the latter calls. Two features of these female calls appeared to be unusual among birds. First, females produced male-like calls at the time of spring and autumn migratory activity and on migration in the wild. Because of this, functional significance of this call remained puzzling. Secondly, the male-like female call unexpectedly combined features of both closed-mouth (closed beak and simultaneous inflation of the ‘throat sac’) and open-mouth (prominent harmonic spectrum and the maximum neck extension observed at the beginning of a sound) vocal behaviors.ConclusionsThe Cuculus vocalizations outside the reproductive season remain poorly understood. Here, we found for the first time that Oriental Cuckoo females can produce male-like calls in that time. Because of its rarity, this call might be an atavism. Indeed, female male-like vocalizations are still known in non-parasitic tropical and apparently more basal cuckoos only. Therefore, our findings may shed light on the evolution of vocal communication in avian brood parasites.

Highlights

In the last decade, enigmatic male-like cuckoo calls have been reported several times in East Asia
When and on what circumstances was male‐like vocalization reported in captivity and in the wild In captivity, we recorded male-like vocalization of females at the time of spring and autumn migratory activity (Fig. 3)
The origin of enigmatic male‐like cuckoo calls: from whom and when? Recently, cuckoo calls exhibited a combination of vocal traits of both Oriental Cuckoo and Common Cuckoo that were reported from East Asia (Moores 2013, 2015; Lastukhin 2015; own data SM)

Summary

Introduction

Enigmatic male-like cuckoo calls have been reported several times in East Asia. These calls exhibited a combination of vocal traits of both Oriental Cuckoo (Cuculus optatus) and Common Cuckoo (Cuculus canorus) advertising calls, and some authors suggested that the enigmatic calls were produced by either Common × Oriental Cuckoo male hybrids or Common Cuckoo males having a gene mutation. Enigmatic cuckoo calls have been reported in eastern Asia: in South Korea (Moores 2013,2015) and in Primorski Krai of Russian Far East (Lastukhin 2015; own data SM). The photos of three calling bird have been taken On these photos, traits necessary for exact species and/or sex identification were poorly seen (Moores 2015). Other authors argued that enigmatic calls apparently were not caused by a single rare mutation, as they have been recorded and/or heard several times (Gluschenko et al 2016)

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