Comparison of acoustic and traditional point count methods to assess bird diversity and composition in the Aberdare National Park, Kenya

Abstract

Afromontane forests, like those in the Aberdare National Park (ANP) in Kenya, sustain unique avifaunal assemblages. There is a growing need for biodiversity inventories for Afromontane forests, especially through the utilisation of unskilled observers. Acoustic surveys are a potential aid to this, but more comparisons of this technique with that of traditional point counts are needed. We conducted a systematic survey of the ANP avifauna, assessing whether acoustic and traditional surveys resulted in different species richness scores, and whether this varied with habitat and species characteristics. We also investigated the role of habitat and elevation in driving variation in species richness. The ANP provides habitat types including scrub, moorland, montane, hagenia and bamboo forests. Overall, the surveys yielded 101 identified species. The acoustic method resulted in higher species richness scores compared to the traditional method across all habitats, and the relative performance of the two methods did not vary with habitat type or visibility. The methods detected different species, suggesting that they should be used together to maximise the range of species recorded. We found that habitat type was the primary driver of variation in species richness, with scrub and montane forest having higher species richness scores than other habitats.

Autonomous sound recording outperforms human observation for sampling birds: a systematic map and user guide

“…Also, combining point counts with acoustic recordings can support observers with limited ornithological experience (Wheeldon et al. ). Presence/absence data from sound recordings can be merged with point count data, leading to more complete assessments of the bird communities (McGrann and Furnas ).…”

“…Reviewers can verify the data obtained from less experienced ornithologists (Wheeldon et al. ). Venier et al.…”

“…), and sound recordings are easier to process with little ornithological experience, thus increasing the number of available surveyors (Kułaga and Budka , Wheeldon et al. ). Moreover, data can be sent to ornithologists or accessed online from anywhere (see, for example, BioSounds, Fig.…”

“…There is usually considerable overlap in the species detected by each method (Darras et al 2018a) but data from both methods can be combined to detect all unique species (Leach et al 2016). Also, combining point counts with acoustic recordings can support observers with limited ornithological experience (Wheeldon et al 2019). Presence/absence data from sound recordings can be merged with point count data, leading to more complete assessments of the bird communities (McGrann and Furnas 2016).…”

“…Here, we depict updated results of the same meta-analysis, which now includes four new studies and one that was previously not considered (Campbell and Francis 2011, Hingston et al 2018, Kułaga and Budka 2019, Wheeldon et al 2019 in Fig. 3.…”