Descrizione 1
Jacopo G. Cecere, Simona Imperio
The indicator provides an overview of the health status of common migratory passerine bird populations in Europe by assessing their resilience to climate change. Rising spring temperatures due to global warming trigger an earlier onset of vegetation growth which in turn leads to, an earlier peak in insect availability. If migratory birds do not adjust their arrival at breeding sites accordingly, they may struggle to find sufficient prey to feed their chicks. A failure to anticipate migration timing translates into lower resilience to climate change, ultimately threatening population survival.
This study examines the temporal variation in the arrival dates of migratory passerines at stopover sites used after crossing the Sahara and the Mediterranean Sea during their spring migration from Africa to European breeding grounds. Based on the analysis of migration timing for 10 bird species recorded at 26 ringing stations participating in ISPRA’s Piccole Isole Project over a 36-year period (1988–2023), the study found that 40% of the species exhibitmigration shifts that are too slow (advancing by only about one day every seven or more years) to effectively counteract the impacts of climate change.
The indicator is based on data collected through the Piccole Isole Project, coordinated by ISPRA and continuously active since 1988. The project aims to study and monitor the migration phenology of passerine birds that winter south of the Sahara using bird-ringing techniques. The Piccole Isole Project follows standardised bird-ringing protocols at key stopover sites for passerines during spring migration (including small islands and coastal sites), from April 16th to May 15th each year.
The indicator considers 10 passerine species: Common Redstart, Common Nightingale, Whinchat, European Pied Flycatcher, Common Reed Warbler, Sedge Warbler, Melodious Warbler, Garden Warbler, Wood Warbler, and Eurasian Golden Oriole. For each species, the temporal variation in the median passage date at the sampling sites was analysed over the 1988–2023 period, accounting for site-specific variations in migratory timing across the 26 stations involved in the project.
To assess the resilience of small migratory birds to climate change by analysing changes in the timing of their spring migration for 10 bird species.
Birds Directive (2009/147/EC): Objective: to maintain bird species in a favourable conservation status.
Bonn Convention – CMS (Convention on Migratory Species): Objective: to ensure the good conservation status of migratory species.
Law 157/92 – Rules for the Protection of Wild Homoeothermic Fauna and Hunting Regulations: Objective: to maintain bird species in a favourable conservation status.
Descrizione 2
Both, C., & Visser, M. E. (2001). Adjustment to climate change is constrained by arrival date in a long-distance migrant bird. Nature, 411(6835), 296-298.
Jonzén, N., Lindén, A., Ergon, T., Knudsen, E., Vik, J. O., Rubolini, D., ... & Stervander, M. (2006). Rapid advance of spring arrival dates in long-distance migratory birds. Science, 312(5782), 1959-1961.
Møller, A. P., Rubolini, D., & Lehikoinen, E. (2008). Populations of migratory bird species that did not show a phenological response to climate change are declining. Proceedings of the National Academy of Sciences, 105(42), 16195-16200.
The sampling period (16 April – 15 May) adequately covers the migration period for a significant portion of species, including the 10 analysed. However, it does not encompass all species recorded in the Piccole Isole Project.
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Qualificazione dati
Bird ringing database, managed by the ISPRA Bird Ringing Section. See the map viewer of the ISPRA National Biodiversity Network for data consultation: http://geoviewer.nnb.isprambiente.it/mapreacter/#/
National
1988-2023
Qualificazione indicatore
The indicator is calculated based on 10 passerine species: Common Redstart, Common Nightingale, Whinchat, European Pied Flycatcher, Common Reed Warbler, Sedge Warbler, Melodious Warbler, Garden Warbler, Wood Warbler, and Eurasian Golden Oriole.
For each species, the median capture date (representing passage and migration timing) was calculated annually at each ringing site participating in the Piccole Isole Project. A linear model was then constructed for each species, with the annual median capture date for each site as the dependent variable and the year as the independent variable.
The median date was only calculated for cases where at least three individuals were captured at a site within a season (16 April – 15May); typically, the number of birds captured per station and season is significantly higher than three. To account for potential site-specific effects, such as geographical location (e.g., birds from Africa reaching lower latitude sites earlier than higher latitude ones) and differences among migratory populations of the same species, the capture site was included as a random factor in the model.
The indicator presents an apparently favourable scenario for 60% of the analysed migratory species. However, 40% of the species do not significantly advance their spring migration timing, indicating a low level of resilience to climate change.
The trend is negative, as historical data analysis shows that:
- European Pied Flycatcher advances its median migration date by 1 day every 12.1 years
- Common Nightingale by 1 day every 10.2 years
- Melodious Warbler by 1 day every 10 years
- Common Reed Warbler shows no change in its median migration date over the 36 years analyzed
In contrast, an advancement greater than 1 day every 7 years is considered favourable, as it is likely sufficient to counteract the challenges posed by rising spring temperatures—assuming no additional threats such as habitat modification.
A more favourable situation was observed for:
- Common Redstart (1 day every 6.3 years)
- Sedge Warbler (1 day every 6.1 years)
- Wood Warbler (1 day every 6.4 years)
- Eurasian Golden Oriole (1 day every 6.4 years)
- Whinchat (1 day every 6.9 years)
- Garden Warbler (1 day every 7.3 years)
Dati
Figure 1: Trend of median passage date at Small Islands Project ringing stations during 1988-2023 of 10 species of trans-Saharan migratory passerines common in Europe during spring migration
ISPRA
On the y-axis, the value 100 corresponds to April 10, while the value 140 corresponds to May 20. The number of active ringing stations each year varies over the years (min 2 in 1989, max 15 in 2012) and not all of them contact the 10 target species each year.
Abstract: Trend of median passage date at the Small Islands Project ringing stations during 1988-2023 of the Common Whitethroat during spring migration
Resilience to climate change directly and indirectly affects the conservation status of migratory bird species. Several scientific studies have demonstrated a relationship between changes in migration timing and the conservation status of migratory birds in Europe: species that have not adapted to global warming by significantly advancing their migration dates are now in poor conservation status.
The analysis of the 10 considered species shows a biologically significant advancement in spring migration timing for the Common Redstart, Sedge Warbler, Wood Warbler, Eurasian Golden Oriole, Whinchat, and Garden Warbler. These species appear to exhibit a certain degree of resilience to global warming.
In contrast, the Common Reed Warbler, Common Nightingale, Melodious Warbler, and European Pied Flycatcher show either no advancement or a migration shift that is too slow (1 day every 7+ years), likely failing to adequately respond to the environmental changes caused by rising spring temperatures (Figure 1).