Acoustic monitoring of migrant birds in the Pyrenees

Acoustic monitoring of migrant birds in the Pyrenees

Guest Blog by Robert Manzano Rubio Biologist & Wildlife Guide robertmanzanorubio@gmail.com

Bird migration is definitely one of the most-studied natural phenomena, probably due to its complexity and large geographical scale of occurrence, which makes it so fascinating. Several hypotheses have been raised about the mechanisms birds use for navigation, how they determine when to depart and in what direction (Newton, 2008).

Whilst diurnal migration is relatively easy to monitor and sample for obvious reasons, studying migration occurring at night is more challenging. Some methods used to do so include (Farnsworth, 2005):

• Moon-watching;
• Use of meteorological radars; and
• Acoustic sampling.

Acoustic sampling in a specific area relies on birds’ vocalisations emitted at night during their migratory journeys. The ‘listening’ process can be carried out (1) actively, by being present in the sampling area during the sampling period, or (2) passively, by deploying an acoustic recording device which records every sound detected during the sampling period and creates audio files; these can be analysed later, in order to detect the species present and their calling rates.

Figure 1: Study area

This autumn (2020) a research project will be undertaken in the Eastern Pyrenees that aims to reveal nocturnal migrant bird diversity passing through the area. One objective is to test the performance of “AudioMoth”, a low cost passive audio recorder (Hill et al, 2019). Under the Oriol de Bolòs 2019 Scholarship from the Museu dels Volcans and the Institut de Cultura de la Ciutat d’Olot, together with the support of Alar Ecology and the Consorci d’Espais d’Interès Natural del Ripollès, the project aims to:

1. Determine the existence of a nocturnal migratory flyway over the Comanegra mountain range in La Garrotxa county (Catalunya, Spain) in autumn. The range is one of the easternmost locations of the Pyrenees over 1000 m a.s.l. (Figure 1);
2. Reveal the species composition of the flyway, including scarcer species for the region (e.g. waders or ducks); and
3. Compare the performance of the Open Acoustics AudioMoth and the Wildlife Acoustics Song Meter SM4 recorders.

Several AudioMoth units and a Song Meter SM4 will be placed along the mountain range and at other locations nearby that could potentially act as a migratory pass. The devices will be recording at night continuously.

We would like to thank Alar Ecology for supporting this project and offer this blog contribution and further posts to update you in the future.

References

Newton, I. The Migration Ecology of Birds. (Academic Press/Elsevier, 2008).

Farnsworth, A. Flight calls and their value for future ornithological studies and conservation research. American Ornithological Society 122(3), 733-746 (2005)

Hill, AP, Prince, P, Snaddon, JL, Doncaster, CP & Rogers, A. AudioMoth: A low-cost acoustic device for monitoring biodiversity and the environment. HardwareX 6, e00073 (2019).

Follow Alar Ecology:

• 
• 
•