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 (KU722455). 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.

PLAIN NIGHTJAR Caprimulgus inornatus

Currently listed as vagrant with just two observations from Djibouti (Redman et al. 2011) but we recorded the species as fairly common in 2014. It is considered a fairly common resident in north-west Somalia, with one record much further east (Ash & Miskell 1998) and is a rather uncommon breeding resident in parts of Ethiopia (Ash & Atkins 2009). We observed this species sporadically on the coastal side of Camp Lemonnier on several different occasions, and once during a visit to Decan Wildlife Refuge. The species was common in the Ambouli River drainage and at Chabelley, an old French airfield c.24 km south-east of Camp Lemonnier (Arta Region). A specimen (USNM 647811) was collected from a group of Plain Nightjars that were crowding around a spotlight at night, on 7 May 2014, near Chabelley (11°31′10″N, 43°10′00″E; 85 m elevation). The specimen was prepared as a study skin with a partial skeleton saved. Body mass was 52.9 g with light fat and no moult. The skull was completely pneumatized, no bursa was present and the testes measured 9×8 mm (left) and 10×8 mm (right). Stomach contents comprised large insects including five grasshoppers (Orthoptera) and a wasp (Hymenoptera). Another sighting of the species, on 2 October 2015, from Camp Lemonnier is available on eBird (P. Kaestner;  http://ebird.org/ebird/view/checklist/S25404346). We did not observe the species during the 2016 survey. The specimen record and our observations indicate that the species may be more seasonally common than thought, with more detailed observations being warranted to further document the status of Plain Nightjar in Djibouti.

LESSER MASKED WEAVER Ploceus intermedius

A male was mist-netted on 5 February 2016 at Camp Lemonnier in an area of Prosopis sp. scrub near the east end of the installation. The bird (USNM 653247) was photographed (Fig. 1) and prepared as a skeleton (feathers saved) because it represents the only osteological specimen of the species in the Smithsonian collection. The testes were not enlarged (2× 1 mm), there was no bursa present, the skull was 100% pneumatized, and the bird was undergoing head and scattered body moult. Body mass was 18.1 g and trace fat was observed. Ash & Atkins (2009) indicated that the species is known (without evidence of breeding) from a cluster of tetrads close to the Djibouti border in Ethiopia, from where its distribution extends mainly along the Rift Valley. Ash & Miskell (1998) reported a breeding pair in northern Somalia among a colony of Rüppell's Weavers P. galbula and our bird was mist-netted with several of the last-named species. We only observed this single individual during the winter survey of 2016. Prior to this, Welch & Welch (1992) observed a male building a nest on 26 March 1987 near the small town of 'As ‘Ela (11°00′N, 42°06′E; 255 m elevation) in far southern Dikhil Region (132 km south-west of Djibouti City near the border with Ethiopia) and Laurent (1990) reported three nests on 28 December 1989 at the same location. Ours is the first specimen record of Lesser Masked Weaver for Djibouti, and is morphologically consistent with nominate P. i. intermedius in having an orange-chestnut hindcrown and yellow nape (Fig. 1).

Figure 1.

Male Lesser Masked Weaver Ploceus intermedius, Camp Lemonnier, Djibouti, 5 February 2016, in the late stages of definitive moult showing orange-chestnut hindcrown feathers and diagnostic creamy-white eye (Carla J. Dove)

The date of collection (5 February) and the fact the bird was an adult (skull ossified) male moulting from non-breeding (eclipse) into breeding (nuptial) plumage may shed light on the status of the species in Djibouti. In most dimorphic Ploceidae, the male does not moult into breeding plumage until at least two years of age at which point they alternate between breeding and non-breeding plumages (Fry & Keith 2004). One of the males (USNM 247367) in the Smithsonian's collection from Sadi Malk (near modern-day Awash, Ethiopia, c.450 km south-west of Camp Lemonnier) was collected on 31 January 1912, during the Child's Frick Expedition, by Edgar Mearns and exhibits less advanced adult plumage on the head and throat than our specimen.

The species is presumed resident where it occurs, and details of movements away from breeding areas are not well described. The greatest recorded distance travelled by a ringed individual was 74 km in South Africa (Craig 2010). Craig (2010) considered the species to be a wet-season visitor to South Sudan (rainy season mainly May–October), but given the distance it is unlikely that our specimen was headed there. In Ethiopia it is a locally very common breeding resident (Ash & Atkins 2009).

Unless it is discovered to be a longer distance migrant in the future, this specimen further documents this species presence in or very near Djibouti and underscores the need to better document the movements and breeding status of Lesser Masked Weaver.

Our surveys of Camp Lemonnier in 2014 and 2016 were very brief and represent only two short seasonal snapshots of the area's biodiversity. However, our observations indicate that the area is under-studied and in need of additional surveys over longer time periods to more completely document the biodiversity of Djibouti. Given the rapid growth of this region in the Horn of Africa for military and commerce purposes, detailed biodiversity surveys should be a priority before critical conservation areas are designated for development.