Research Grasshopper Warbler migration


At a time when populations of many trans-Saharan migrants are declining, learning more about their stopover sites on migration is vital to their conservation. Studying the clues given by their migration strategy can shed light on where birds might be stopping on their way south. One such clue is gained by observing the amount of fat a bird accumulates before it starts the next leg of its migration. A recent paper by Wetland Trust and the BTO, using ringing data for Grasshopper Warblers in Portugal, has shown that, unlike in some trans-Saharan migrants, very few individuals of this species accumulate sufficient fat reserves to make it south of the Sahara without at least one more refuelling stop. Thus, currently unknown sites in north Africa appears to be of strategic importance to migrating Grasshopper Warblers in spring.

The paper also looks at the return migration of Grasshopper Warblers in spring. Compared to autumn birds in Portugal, spring birds in Senegal were relatively slower in fuelling up for their northbound flight, probably because of the constraints of food availability during the Saharan dry season. Grasshopper Warblers began to leave Senegal as early as mid-January and are thought to spend up to two months in north Africa before continuing their journey north to the breeding grounds.

Grasshopper Warbler
Grasshopper Warbler, Langton Matravers, Dorset (Photo: Simon Johnson)

It's perhaps not too surprising that little is known about Grasshopper Warbler migration. Records in spring are widespread and common, with migrant males proclaiming their presence with their distinctive reeling song; but autumn records are decidedly scarcer with birds skulking in dense undergrowth and seldom making their presence known. One of the most accurate ways of surveying Grasshopper Warbler numbers in autumn is through ringing, and nowhere in the UK is this more productive than at Titchfield Haven NNR (Hants). Trevor Codlin has this year ringed a remarkable 950 Grasshopper Warblers at Titchfield Haven. More than half of those were ringed in autumn: proof that many Grasshopper Warblers go undetected each autumn.


Bayly, N. J., Rumsey, S. J..R., Clark, J. A. (2011). Crossing the Sahara desert: migratory strategies of the Grasshopper Warbler Locustella naevia. Journal of Ornithology 152 933-946.

Related pages

Grasshopper Warbler Grasshopper Warbler

Related articles

Research Global warming risk for wildlife in prime habitats Research Global warming risk for wildlife in prime habitats
Animals living in areas that are ideally suited to their species’ needs have less chance of coping with climate change, new research suggests. read on read on
Research Song diversity hints at Hermit Thrush's evolutionary past Research Song diversity hints at Hermit Thrush's evolutionary past
A new study has provided the first thorough overview of geographic variation in Hermit Thrush song structure and its evolution. read on read on
Research Radar reveals steep declines in Kauai's seabird populations Research Radar reveals steep declines in Kauai's seabird populations
A new study from The Condor: Ornithological Applications has concluded that populations of two endangered seabirds, Hawaiian Petrel and Newell's Shearwater, have exhibited worrying declines on the Hawaiian island of Kauai in recent years. read on read on
Research Migratory birds can't keep pace with spring Research Migratory birds can't keep pace with spring
The arrival of North American migrant birds has evolved to coincide with the onset of spring, but recent eBird data indicate that such timings are now becoming less synchronised. read on read on
Research Swamphens signal dominance with fleshy faces Research Swamphens signal dominance with fleshy faces
What's in a face? In addition to their plumage, Australasian Swamphens convey information about their status through their faces. read on read on

The information in this article was believed correct at the time of writing. BirdGuides accepts no responsibility for errors, or for any consequences of acting on information in the article. The opinions expressed are those of the author(s) and are not necessarily shared by BirdGuides Ltd.

hide section Reader comments (0)

No comments so far.

Back to top Back to top

Latest edition Latest edition
Search articles Search articles
All articles All articles
Popular articles Popular articles
Privacy Policy | Terms of Use | Terms of Sale | Cookie Policy | About us | Advertise | Contact us
BirdGuides, Warners Group Publications PLC, The Chocolate Factory, 5 Clarendon Road, London N22 6XJ
© 2017 BirdGuides and Warners Group Publications plc. All Rights Reserved. Company Registered in England no. 2572212 | VAT registration No. GB 638 3492 15
Sales: or tel. 0800 919391 · International Sales: +44 (0)1778 391180 · Office: or tel. 020 8826 0934

Fatbirder's Top 1000 Birding Websites