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The bird dawn chorus

Bibliography

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  • 2020 in: T. Aubin, N. Mathevon (eds.), Coding Strategies in Vertebrate Acoustic Communication, Animal Signals and Communication 7, pp.45-90. Springer, Cham, Switzerland. The dawn chorus revisited
Press releases

The bird dawn chorus

The bird dawn chorus has fascinated humans since ancient times, but still today numerous questions remain unclear. Diego Lluisa and I have examined in detail the existing literature on this topic, and we have tried to cover from the first descriptive studies to recent multidisciplinary approaches, reviewing the physiological, behavioural and environmental factors affecting dawn chorus.

In our review, we provide a critical assessment of the supporting evidence for the functional hypotheses proposed so far to disentangle its proximal and ultimate causes. We find that, despite the latest empirical and theoretical studies, there is still a good degree of confusion, and that four out of the nine hypotheses proposed so far in the literature have not been empirically tested.

We show that most of these hypotheses are not incompatible with each other, and that their explanatory value changes depending on the species and the season. We argue that a single explanation may not be a reasonable expectation. The best-supported hypotheses for early singing provide three complementary lines of explanation: (1) singing at dawn has a relatively low energetic cost, most likely because it does not interfere with feeding; (2) is optimal to manipulate female mating or settle territory boundaries; and (3) may promote a handicap mechanism that prevents dishonest signalling.

Thus, it follows that a combination of hypotheses based on both an optimality standpoint and costliness assumptions is needed to understand the phenomenon. We provide a series of specific suggestions for further research, since despite the huge existing literature, there are still several key elements missing.

 

Diego Gil

 

 

Pictures

  • Ammodromus humeralis