CHIRPS – Connecting Health Indicators, Resources, ReProductive Success and Soundscapes on bird vocal behavior in relation to land use intensity

• Applicant: Dr. Laura Schille
• Subject Area: Ecology of Land Use ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569058886

Land use change is a major driver of avian biodiversity loss across European habitats, largely due to the depletion of birds’ food resources. Among these, arthropod communities are particularly affected, though impacts vary across taxa. Arthropods are essential prey for most birds during the breeding season, even those not strictly insectivorous. A decline in their abundance or quality can impact bird health, parental provisioning, and ultimately, breeding success. Additionally, in resource-poor environments, birds must balance foraging with other activities, leading to time trade-offs between searching for food and singing. These trade-offs may also fluctuate diurnally and seasonally, as individuals prioritize foraging or singing depending on the time of day and seasonal energy demands. Using existing data from the Biodiversity Exploratories and an automated bird song recognition algorithm, the CHIRPS project will test whether increasing land use intensity and declining arthropod prey availability reduce bird vocal activity. This effect is expected to fluctuate daily, with singing prioritized at dawn and foraging increasing as energy demands peak, and seasonally, with stronger constraints during the breeding period. Additionally, CHIRPS will assess how the availability of specific arthropod groups affects vocal activity in bird guilds with distinct diets. To be able to separate the influence of prey availability from other land use factors, CHIRPS includes a food supplementation experiment in forest habitats (MIPs) with varying land use intensity, focusing on the great tit (Parus major) as a model species. By combining arthropod sampling in trees, where great tits primarily forage, acoustic recordings and nestbox video monitoring, the project will analyze how land use intensity and variations in arthropod availability and quality (natural or supplemented) influence prey selection, vocal activity, and breeding success in great tits pairs. We hypothesis that in intensively managed forests, great tits rely more on supplementary food due to limited access to high-quality natural prey (e.g., lepidopteran larvae). Further, reduced arthropod availability is predicted to constrain both great tits’ vocal activity supporting the hypothesis of a foraging-singing trade-off and their breeding success, supporting the food limitation hypothesis. Finally, CHIRPS relies on advanced ecoacoustic analyses to isolate great tit vocalizations in recordings and quantify acoustic traits such as rhythm, duration, and vocalization energy. It will test whether these acoustic traits are an honest signal of individual health status, likely influencing mate selection and predicting potential breeding success. If confirmed, a predictive model will be developed to estimate high breeding success probabilities based on great tits’ vocal traits. This could pave the way for new, non-invasive methods to monitor bird health status and reproduction in diverse environmental contexts.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1374: Biodiversity Exploratories