Locustella fluviatilis

Dove, Carla J., Saucier, Jacob, Whatton, James F., Schmidt, Brian & Roble, Houssein R., 2017, First record of River Warbler Locustella fluviatilis and additional records for Plain Nightjar Caprimulgus inornatus and Lesser Masked Weaver Ploceus intermedius in Djibouti, Bulletin of the British Ornithologists’ Club 137 (1), pp. 67-70 : 67-68

RIVER WARBLER Locustella fluviatilis

Breeds in central and eastern Europe east to south-west Siberia and north-west Kazakhstan, and is a long-distance migrant to the southern African countries of Zambia, Malawi, Botswana, Zimbabwe, Mozambique and northern South Africa, probably migrating via narrow routes through the Middle East and north-east Africa (Pearson 2006). Ash & Atkins (2009) and Redman et al. (2011) listed it as an uncommon passage migrant in the central Rift Valley in September –November and April–May but did not list any records for Djibouti. Two specimens were obtained during the spring 2014 survey. On 11 May 2014, a male ( USNM 647876 ) was found dead on the ground under a small sapling between the armoury building and the religious chapel at Camp Lemonnier. The specimen was prepared as a skeleton (feathers saved), body mass was 20.7 g, the stomach was empty, and heavy fat was noted at the time of preparation. The testes were minute (2 × 1 mm). Another specimen ( USNM 647822 ) was collected on 13 May 2014 on the beach near Camp Lemonnier. Prior to collection, the bird was observed skulking inside a small isolated bush among the sand dunes. This specimen was prepared as a study skin with a partial skeleton. The bird was a male (testes; left = 3 × 2 mm, right = 2 × 2 mm) and the skull was 25% pneumatized. The preparation notes record extremely heavy fat and body mass was 24.6 g.

We did not record any additional River Warblers during the winter 2016 (1 February–2 March 2016) survey. DNA barcoding (Hebert et al. 2003) was conducted on USNM 647822 and the resulting mtCOI sequence was run through a BLAST search (December 2015). The top hit was GQ482077 ( L. fluviatilis ), with 100% pairwise identity and 99.7% query coverage. The mtCOI sequences for this specimen is deposited in GenBank ( KU 722455). Morphologically, the streaked breast and pale-tipped undertail-coverts separate this species from the closely related Savi’s Warbler L. luscinioides which has been recently recorded in Djibouti (Hering et al. 2015). Heavy fat reserves and reduced testes size on both specimens indicates that these individuals were migrants.