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Great Reed Warblers Showed Similar Vigilance to Cuckoo, Sparrowhawk and Turtle Dove Calls

Great reed warbler singing among green reeds
Research · Behaviour

Incubating female great reed warblers (Acrocephalus arundinaceus) showed similarly high vigilance when they heard calls from a common cuckoo (Cuculus canorus), a Eurasian sparrowhawk (Accipiter nisus) or a harmless European turtle dove (Streptopelia turtur), according to a study published on 28 February 2026.

The researchers used playback experiments and observations of naturally occurring sounds in two great reed warbler populations in Czechia and Poland exposed to contrasting levels of cuckoo brood parasitism. This allowed them to test whether females adjusted their alertness to the type of sound or to the local likelihood of cuckoo parasitism.

Responses Did Not Differ Among the Three Playback Types

Vigilance was measured through behaviours such as turning the head, raising the head into an alert posture and leaving the nest. The researchers found no clear differences in these responses between playbacks of the bubbling call of a female cuckoo, the chattering call of a sparrowhawk and the advertising call of the turtle dove.

Responses also did not differ between the two study populations despite their contrasting brood-parasitism pressure. Observations of reactions to naturally occurring calls likewise found no clear difference between threatening and non-threatening species.

The Results Supported Generalised Acoustic Vigilance

The authors tested the parasite-assessment hypothesis, which predicts that hosts should adjust vigilance according to local cuckoo pressure. The similar responses in the two populations did not support that prediction.

Instead, the authors propose a generalised acoustic vigilance hypothesis: great reed warblers may maintain consistently high vigilance around the nest rather than repeatedly distinguishing among acoustic threats. They suggest that such a strategy could help females respond to several risks, including brood parasites, predators and other nest intruders.

Sources and image credit

  1. Honza, M., Capek, M., Czyż, B., Trnka, A., Večeřová, G., & Samaš, P. (2026). Hypervigilance as an adaptive strategy to multiple risks in a songbird. Behavioral Ecology, 37(2), araf139. https://doi.org/10.1093/beheco/araf139Primary peer-reviewed article published 28 February 2026. Incubating female great reed warblers in two populations with contrasting brood-parasitism pressure were exposed to calls of female common cuckoo, Eurasian sparrowhawk and European turtle dove. Vigilance behaviours did not differ between playback treatments or populations, and responses to naturally occurring threatening and non-threatening calls also showed no differences.

Image: Zeynel Cebeci — wild great reed warbler photographed at Kesmeburun, Osmaniye, Turkey, 13 June 2020; Wikimedia Commons. Representative image for this story; not presented as an animal or scene from the reported study or event. · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Behaviour

SPECIES IN THIS STORY

Species in this story

Common Cuckoo Cuculus canorus Explore species Eurasian Sparrowhawk Accipiter nisus Explore species

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