River Warbler vs Common Grasshopper Warbler

In short

The River Warbler and Common Grasshopper Warbler are both plain-backed, brown warblers, but the River Warbler is slightly larger with a more robust appearance. Key differences include the River Warbler's broader, more graduated tail and its distinctive insect-like song compared to the Grasshopper Warbler's reeling trill.

Identification tips

• Tail shape: River Warbler has a broader, more graduated tail.
• Song: Listen for the River Warbler's insect-like song versus the Grasshopper Warbler's reeling trill.
• Habitat: River Warbler is more likely near water, while Grasshopper Warbler prefers drier areas.
• Plumage tone: Look for the olive-brown tone in River Warbler compared to the more uniform brown of the Grasshopper Warbler.

Size

River Warbler is slightly larger and bulkier than the Common Grasshopper Warbler.

Plumage

Both species have plain brown upperparts, but the River Warbler has a more olive-brown tone with a poorly marked buffish supercilium, while the Common Grasshopper Warbler is more uniformly brown without the olive tinge.

Behaviour

Both species forage low to the ground, but the River Warbler often creeps among low vegetation, whereas the Common Grasshopper Warbler is more likely to be seen running among grass.

Habitat

Both species inhabit dense, low vegetation, but the River Warbler prefers wetter habitats like riverbanks, while the Common Grasshopper Warbler is found in drier grasslands and scrub.

Voice

The River Warbler has a high-pitched, throbbing, insect-like song, whereas the Common Grasshopper Warbler produces a continuous, reeling trill.