Wild Birds

Common Chiffchaff Welfare and Early Migration Risks

The common chiffchaff is often the first migrant warbler to return in spring, making it a beloved harbinger of the season, but early arrival carries welfare risks from late cold snaps.

Key Facts

Chiffchaffs arrive in the UK from late February, weeks before most other warblers
A small population now overwinters in the UK, boosted by climate warming
Their two-note call -- chiff-chaff -- gives them their name and is one of the simplest bird songs
UK breeding numbers have increased by around 60% since the 1970s
Chiffchaffs feed almost entirely on small invertebrates, making them sensitive to cold weather that suppresses insect activity

Welfare Considerations

Early-returning chiffchaffs are vulnerable to late winter cold snaps that suppress insect emergence. Individuals that arrive before sufficient invertebrate prey is available face starvation and must retreat to southern coastal areas or die. Climate change has extended the safe arrival window on average, but increases the variance of late frost events, maintaining welfare risks for early migrants.

What You Can Do

Support the BTO migration monitoring network to track arrival dates over time
Advocate for woodland and scrub management that maintains warm, sheltered insect-rich edges
Contribute chiffchaff spring arrival records to citizen science databases
Reduce pesticide use in gardens to ensure early insect emergence for returning migrants
Plant early-flowering plants that support invertebrates from February onwards