Blackcap Becomes Switzerland’s Most Common Bird, Overtaking Chaffinch

The blackcap has become the most common bird species in Switzerland, overtaking the chaffinch, according to the 2025 bird monitoring programme by the Swiss Ornithological Institute.

Researchers report that there are now nearly one million breeding pairs of blackcaps across the country. The species has expanded significantly, benefiting from forest growth at higher altitudes and changing environmental conditions.

The study also suggests that more birds are choosing to remain in Europe during winter instead of migrating south, which has contributed to the blackcap’s population increase.

At the same time, chaffinch numbers have declined. Scientists say the reasons for this decrease remain unclear, describing it as puzzling due to the lack of identifiable causes.

Other common species such as sparrows and blackbirds continue to rank among the top ten most widespread birds in Switzerland. However, urban species like the street pigeon do not appear in the top 50.

The monitoring programme involved around 300 staff members from the Swiss Ornithological Institute, who dedicated more than 3,000 hours to collecting data on breeding bird populations across the country.

Experts say the findings highlight how climate change, habitat shifts, and migration behavior are reshaping Switzerland’s bird populations.