Avian surveys near Camp Lemonnier and Day Forest, Djibouti, Africa

Two brief biodiversity surveys were conducted near Camp Lemonnier, Djibouti, in May 2014 and February 2016, and to the Day Forest (Forêt du Day) in February 2016. Our complete avian checklist of 143 species, with 96 species preserved as museum specimens is presented here. We document nesting for Spur-winged Lapwing Vanellus spinosus (Linnaeus, 1758), the occurrence of Crimson-rumped Waxbill Estrilda rhodopyga Sundevall, 1850, and confirm Little Tern Sternula albifrons (Pallas, 1764) in Djibouti. We comment on observations for the Critically Endangered Djibouti Spurfowl Pternistis ochropectus (Dorst & Jouanin 1952), and the Endangered Egyptian Vulture Neophron percnopterus (Linnaeus, 1758), and a previously noted Fringillidae ( Crithagra sp. ) Swainson, 1827 from the Day Forest. Hybridization between Somali Sparrow Passer castanopterus Blythi,1885 and House Sparrow Passer domesticus (Linnaeus, 1758) is documented with voucher specimens. Although these surveys and taxa lists represent brief inventories for the areas visited, they provide a foundation and reference for future work in this understudied region in the Horn of Africa.


Introduction
The Republic of Djibouti is a small country (23,200 km 2 ) in the Horn of Africa that lies between 10° and 13°N, and 41° and 44°E. Bordered to the west by Ethiopia, to the north by Eritrea, and to the southeast by Somalia ( Fig. 1), Djibouti is a relatively young country, gaining independence from France in 1977. The country has 372 km of coastline along the Red Sea and the Gulf of Aden. Djibouti is diverse in landscape for its small size, with vast areas unoccupied by humans. Approximately 884,000 people inhabit Djibouti with more than 75% living in cities, predominantly in Djibouti City (Central Intelligence Agency Factbook, Djibouti: https://www. cia.gov/library/publications/the-world-factbook/geos/ dj.html). The majority of the country's land area consists of flat gravel plains, plateaus, xeric grasslands, deserts, acacia scrub, high elevation mountain ranges (e.g. Moussa Ail, Goda and Mabla Mountains; over 2,000 m), a low elevation salt lake (Lake Assal; -157 m), rugged volcanic fields, and coastal mangrove areas that create interesting and diverse habitats (Magin 2001). Few detailed or comprehensive biological inventories exist for Djibouti. Bird species are included in Redman et al. (2009Redman et al. ( , 2011 and Important Bird Areas are covered in Magin (2001). Welch (1984, 1988) provided species lists and described the autumn bird migration throughout the country. A recent, brief survey by Buechley et al. (2019), and other general bird lists are included in unpublished bird trip reports by Borrow (2010), Redman (2012), and on current searches of eBird (Sullivan et al. 2009) for Djibouti.
The Smithsonian Institution's National Museum of Natural History (NMNH) conducted biological surveys of birds, mammals, herpetofauna, insects and plants in the vicinity of Camp Lemonnier during the spring (30 April-19 May) of 2014 and late winter (1 February-2 March) of 2016, with a short visit made to the Day Forest (Forêt du Day) from 16-21 February 2016 (Fig. 1).
Here we include inventories of avian species observed and collected during these expeditions. These surveys, although brief, help document species diversity and provide foundations for more detailed work to inventory biodiversity, properly document species occurrence, and help identify natural areas that have important conservation implications in this rapidly developing country in the Horn of Africa.

Methods
Study sites. Location 1: Camp Lemonnier and Ambouli River (Figs 2-7). Camp Lemonnier (11.54°N, 043.14°E), currently a U.S. military base, is situated within the Djibouti-Ambouli International Airport in the town of Ambouli, 5.5 km southeast of Djibouti City. Birds were observed and some were collected on the more than 200ha facility (Fig. 2) and adjacent vegetated areas outside the fence line, along the shoreline (Fig. 3), and on the nearby 26-ha Haramous Island (Fig. 4; locally known in English as Turtle Island). In addition, some surveys were conducted in the Ambouli River area near the village of Chabelley located approximately 24 km southeast of Camp Lemonnier, where the small seasonal Ambouli River crosses the road (11. 5194°N,043.0986°E;Figs 5,6). A single visit to Décan Wildlife Refuge (11.5069°N, 043.1833°E) on 16 May 2014 (Fig. 7) recorded field observations only. Due to the proximity and relative homogeneity of habitats, we combine these areas into one generalized location. Coastal habitat near Camp Lemonnier and Haramous Island consists of inter-tidal mudflats with sparse mangrove patches, mesquite (Prosopis juliflora) and Acacia scrub. A stream flows from Camp Lemonnier to the Gulf of Aden. This streambed has undergone recent (2016) landscape construction and now forms a larger area of standing fresh water near the southeastern corner of Camp Lemonnier. Many of these habitats were highly disturbed by human and livestock activity, except for Décan Wildlife Refuge where habitat protections and restoration has allowed for taller and more intact stands of Acacia. Rocky plateaus and sandy fields are typical habitat types near Ambouli River.
Location 2: Day Forest (Figs 8,9). Surveys were confined to an area accessible by truck or foot from Campement Touristique de la Forêt du Day, a local overnight facility. Although the Day Forest covers a vast area within  the Goda Mountains (Welch and Welch 1984), our short visit focused on a small area (Fig. 8) around the remnants of a building (11.77°N, 042.68°E) that was previously the governor's house (Fig. 9). Rugged nearby areas at higher elevation that were accessible by foot appeared to have denser understory vegetation than lower areas, likely due to difficulty in reaching higher areas for cattle and camel grazing. The Day Forest ranges in altitude from 182-1,783 m (Magin 2001) but we were not able to access the lower more vegetated wadis or spend much time in the highest elevation areas at our location.
Visual surveys (informal) were conducted by all authors with emphasis on and around Camp Lemonnier and Chabelley in Location 1 and the small area within the Day Forest in Location 2. Audio recordings were made (JRS/BKS) on a Marantz® PMD661 recorder with a Sennheiser® ME67 long shotgun microphone and are available from Xeno-canto Foundation (https:// www.xeno-canto.org/). The focus on visual documentation was to provide a checklist of species, and therefore abundance of species was based on group consensus. We defined observations as follows: Abundant = multiple individuals observed daily; Common = at least one individual observed daily; Fairly Common = one to five individuals observed weekly; Uncommon = observed fewer than ten times during survey; Rare/Scarce = observed only once during survey.
Because this biodiversity expedition was a rapid survey, collecting of specimens was opportunistic and often subjected to logistical limitations. We followed the guidelines of Fair et al. (2010) for all avian collecting activities. Gender of collected specimens was determined by internal examination at the time of preparation.

Results
We recorded a total of 143 species of birds, of which 96 have been preserved as museum specimens. Here we provide our complete avian species list (Tables 1, 2) and include noteworthy observations below for some species of interest and for some collected specimens. Observations from 2014 (spring) and 2016 (winter) are separated in Table 1 to highlight potential seasonal differences in the avifauna. From these two brief surveys, Dove et al. (2017)    On the way up the slope to the plateau from our base location we heard or had fleeting glances of several individual birds. The first bird was heard at 0740 hrs but it was not until just after 0800 hrs that we saw another bird in full view. Three additional birds were flushed on the way to the top of the plateau and all observed individuals were shy and skittish and flew quickly after being seen. At 0900 hrs a single Djibouti Spurfowl (Fig. 11) was heard and emerged from the dense vegetation of Rumex vesicarius L. on which it was feeding. After several minutes, the bird flew across the canyon and ducked under the edge of the cliff (1402 m elevation).   Identification. Most observed birds were in breeding plumage (e.g. Fig. 12), as noted by the pink blush coloration on the back and wing-coverts (Redman et al. 2011).
Although it is considered a year-round resident in Djibouti and might be an intra-African breeding migrant (Elliot et al. 2020), it is listed as a non-breeding visitor by Redman et al. (2011).

Remarks.
Adult birds were observed twice in May 2014, and more often in 2016 when more commonly alone than in pairs. One pair was observed in 2016 on Camp Lemonnier in the southeastern corner where recent landscape construction of the runoff streambed was completed.
Remarks. Observations in 2014 included feeding on unidentified species of grasshoppers. One specimen (USNM 647910) collected on 08 February 2014 contained more than 50 grasshoppers (Acrididae) in the stomach. Grasshoppers are listed as one of the main insect food sources by Martinez-Vilalta et al. (2019). Another individual was noted as having pig skin and maggots in the stomach and may indicate that it was feeding at the nearby open garbage dump. It is listed as a non-breeding visitor (Palearctic or intra-African migrant) to Djibouti (Redman et al. 2011).
Identification. This species (Fig. 13) was identified in the field as being smaller than Great White Pelican P. onocrotalus Linnaeus, 1758 with overall gray appearance and pink bill-pouch (Redman et al. 2011).

Remarks.
Commonly seen in 2014 roosting on rock outcrops near Haramous Island but was not observed on Camp Lemonnier until 2016 and likely due to the completion of grading of the runoff stream that created a freshwater pool at the southeastern corner of the base. Immatures and adults were observed singly or in pairs during both surveys. It is listed as a non-breeding visitor to Djibouti (Redman et al. 2011) and is noted as widespread and common on fresh, alkaline, and coastal waters throughout most of the region where it exploits smaller lakes and ponds (Redman et al. 2011).
Identification. This species is listed by the IUCN as Endangered (Birdlife International 2015). The adult is easily recognizable as a white or buffy-yellow-and-white vulture with black wing feathers and a bare orange-yellow face. The immature (Fig. 14) is all brown with long feathers on the back of the head and wedge-shaped tail (Redman et al. 2011). Remarks. This species is one of the nine near threatened bird species in Djibouti (BirdLife International 2019). We observed this species both years as being fairly common at the shoreline near Camp Lemonnier.

Dromas ardeola Paykull, 1805
Crab-plover Figure 15 Collected material. Identification. This plover is easily identifiable in the field by the two black breast band and broad white forehead and supercilium with gray sides of face (Redman et al. 2011 Identification. Both adult birds, identified by white cheeks and neck (Fig. 16) and black crown, throat, and breast (Redman et al. 2011) were common on and around Camp Lemonnier.

Remarks.
A nest of this lapwing was discovered on Camp Lemonnier on 5 May 2014. The four black-spotted, cream-colored eggs (Fig. 17) were in a nest lined with plant material on bare, dry ground that matched the description in . This nest was in close association with fresh water as described by Ash and Atkins (2009)

Identification. Easily recognizable from Eurasian
Whimbrel Numenius phaeopus (Linnaeus, 1758) by the longer and more evenly decurved bill (Fig. 19), and unstriped head (Redman et al. 2011 Identification. This gull was identified by being dark brownish-gray above and across the breast with a distinct white hind-collar (Redman et al. 2011).   Olsen and Larsson (1995). We compared our collected specimens (12) with museum study skins from various subspecific populations of Little Tern at NMNH and found inconsistencies in collected specimens and in museum specimens for characters of concolorous rump and back, and coloration of the brown or black rachis on the outer primaries reported in Gochfeld et al. (2020aGochfeld et al. ( , 2020b. Of the six adult male specimens prepared as study skins, four were in breeding plumage, three of these had no bursas (one specimen did not have bursa notes), indicating adulthood. The white triangular patch extends over the eye on each specimen, but none have tail streamers present, and bills of the four breeding adults were yellow with black tip (Olsen and Larsson 1995). Only two specimens (USNM 653161, 653232), one of which is in non-breeding plumage, have four black outer primaries consistent with descriptions for Saunders's Tern Sternula saundrsi A.O. Hume, 1877 (Gochfeld et al. 2020b) but the number of dark outer primaries is inconsistent among our specimens: four specimens have two dark outer primaries, five specimens have three dark outer primaries and two specimens have four dark outer primaries. Two of the adult specimens are in winter/first summer plumage with black bills and feet (Olsen and Larsson 1995) and with the white forehead patch extending beyond the eye as in Little Tern. Molt was noted in various stages in the collected specimens.

Remarks. Commonly observed in
The concolorous rump, reported as a distinct difference for Saunders's Tern (Gochfeld et. al 2020b) is also inconsistent among our specimens as only three of the collected specimens ( Remarks. Little Tern is listed as a non-breeding visitor with sparse occurrence in Djibouti whereas the very similar Saunders's Tern is considered a resident breeder and fairly common on the coast of Djibouti (Redman et al. 2011). However, due to inconsistency in reported characteristics and in our specimens, all collected specimens were determined to be Little Tern based mainly on the white triangular patch above the eye. Because much inconsistency is noted in museum specimens for rump, primary feather and rachis color, caution is warranted with sight identifications of this species. We believe incorrect sight identifications on eBird (2017), probable lack of tail streamers due to molt at various times of the year, and inconsistent characters among the closely related species has caused the abundance of Saunders's Tern in Djibouti to be overstated. We did not observe any small terns in 2014. More work involving the entire complex of subspecies is needed to confidently identify these terns but our specimens support presence of Little Tern in Djibouti.
Identification. The specimen, an adult female (ovary 5 x 3 mm) bird, was identified by the gray-brown upperparts and narrow white forehead (Redman et al. 2011).

Remarks.
One specimen found washed up on the beach on 2 May 2014. It is listed as a breeding visitor by Redman et al. (2011). This species was not observed alive in Djibouti. Identification. Specimens match C. n. tamaricis Tristram, 1864 by having greyish upperparts or buffish, thinly streaked blackish-brown, crown heavily streaked; broad tawny-buff nuchal collar; white throat patch; underparts buff barred brown. In the field, males have a large white spot on four outermost primaries and broad white tips to two outermost tail feathers; females have smaller wing and tail spots (Cleere 2019b).

Caprimulgus inornatus
Remarks. This species was not observed in 2014 but was commonly seen in 2016 at Camp Lemonnier and Ambouli River. It is listed as a resident breeder in Djibouti (Redman et al. 2011 Identification. The expected subspecies is T. c. hilgerti (Neumann, 1903) based on the geographic location (Fry 2019) but the chin color on specimens is mostly white and the upper belly patches are lighter in pink tone than described for that race in Fry (2019) and as per our comparisons of collections at NMNH. Additionally, male specimens have the forehead and crown light gray-brown tinged with pink as in T. c. cruentus (Hemprich and Ehrenberg,1828) and ear-coverts are light pink-tinged gray, grading to whitish towards cheek and throat. Based on this, we assigned specimens to the nominate subspecies, T. c. cruentus.

Remarks.
Commonly observed during both 2014 and 2016 surveys.
Identification. Adult males easily recognizable by the blue-gray crown, black mask, and chestnut mantle and wings (Fig. 21), and black tail with white patches at base (Redman et al. 2011).
Remarks. This species was abundant in 2014 moving through on spring migration but was not recorded during the 2016 survey.

Identification.
Identified by the all black feathers, deeply forked tail, and red eye (Redman et al. 2011).
Remarks. This species is a known resident breeder in Djibouti (Redman et al. 2011)  Remarks. This species was observed both years but noted as more common in the areas adjacent to Camp Lemonnier in 2016.

Rufous-tailed Scrub Robin
Identification. Identified by the all black tail and pale gray-brown upperparts (Redman et al. 2011 Identification. Males were easily recognizable by the violet band below the green throat and the extensive violet on lower back, rump, and uppertail-coverts (Redman et al. 2011).
Remarks. This species was the most abundant sunbird observed during both surveys and is a common resident in Djibouti (Redman et al. 2011 (Fig. 22) are very similar to the photographs reported to eBird by Kaestner (2015) and by Cohen and Mills (2010). USNM 653437 is a male with wing measurement 70 mm. The gray crown is outlined with chestnut. The back and wing coverts are like Somali Sparrow, but the underparts are much paler that the other two male specimens described here. USNM 653438 is a male with wing measurement 70 mm; the crown is all gray outlined with chestnut and underparts have a light-yellow wash, and the nape and back coloration are consistent with Passer c. castanopterus. USNM 653398 is a male specimen with wing measurement 72 mm; the chestnut crown is mottled with gray and the underparts have a light-yellow wash. The back and wing coverts are like Somali Sparrow. Hybridization identification of female specimens was not attempted.

Remarks.
House Sparrow is known from Djibouti (Ash and Atkins 2009) and has been present there since 1999 (Gedeon et al. 2015). The subspecies in Djibouti, P. d. indicus, is thought to have originated from the Red Sea coast of Arabia (Jennings 2010) and Somalia (Ash and Miskell 1998). P. d. indicus has been reported to hybridize with Somali Sparrow in Somalia (Ash and Colston 1981, Ash and Miskell 1998, Borrow 2010. Borrow (2010), Cohen and Mils (2010), Redman (2012), Caratāo (2018), and Moreiro (2018) have reported possible hybrids in Djibouti on birding websites and to eBird but specimens obtained on these surveys are the first known specimen records of possible hybridization in Djibouti. More study, including genetic analysis and additional voucher specimens, will confirm hybridization between Somali and House Sparrow in Djibouti.
Identification. This waxbill easily identified by the red streak through the eye, crimson rump, and red edges to wing coverts (Fig. 23) (Redman et al. 2011

Discussion
The Smithsonian Institution has not conducted biological surveys in Djibouti since the 1911-12 Child's Frick Expedition to Africa. Edgar Mearns was part of this expedition and spent two days (November 25-26) in Djibouti on his way to "Dire Daoua" (Dire Dawa) Ethiopia in 1911. According to his notes and catalogues (Smithsonian Institution Archives 2018), he collected fewer than a dozen species of birds on his short visit to Djibouti (French Somaliland), but he observed bustards and other birds that we did not record on our recent expeditions. Parts of Djibouti are being rapidly developed for strategic global port transport and military operations (Paris 2019) and as such, faces huge environmental challenges. The beaches and shoreline near Camp Lemonnier are heavily littered with old tires, plastics, and other trash that washes ashore and the area is frequented by local Djiboutian camel and goat herders. Most of the 200 ha within Camp Lemonnier is barren desert landscape that is rapidly being developed along with adjacent areas that are now mainly covered with Acacia/Prosopis scrub. Post-construction landscaping at the southeastern corner of Camp Lemonnier created a large holding area of fresh water inside the facility fence that serves as a safe feeding and resting place for many species of birds. This area attracted many more species of birds in 2016 than observed there in 2014. The Ambouli River wadi near the small village of Chabelley area is heavily used by locals for crafting cobblestones from the nearby rocks that are sold as pavers. Much of the road from Camp Lemonnier to the village of Chabelley was under construction in 2016 by the Chinese Government as part of a new infrastructure project.
The Day Forest, one of the few Afromontane areas in Djibouti, is designated as a protected area by the Djiboutian Government. Although heavy grazing was observed in the area of our survey, inaccessible wadis and cervices in the Day Forest may be refuges for wildlife. The endemic Djibouti Spurfowl lives in Day Forest and is in danger of extinction due to loss of habitat from timber harvest, over grazing and widespread death of the native junipers in these high elevation forests (Fisher et al. 2009). The global populations size was estimated as 285-705 individuals (Fisher et al. 2009). Our frequent encounters with sounds or sightings of Djibouti Spurfowl in the Day Forest gives hope that this species can survive with future management and conservation efforts. Although we observed many signs of cattle and camel grazing at higher elevations near where this bird was observed, we did not have trouble locating this species. Mammalogists on this expedition collected one specimen of Abyssinian Genet Genetta abyssinica Rüppell, 1835 (Ferguson et al. 2018) in Day Forest, a likely predator of the Djibouti Spurfowl (McGowan et al. 2019).
A species of Fringillidae persists in the Day Forest and was observed in 2016. This bird was located (no specimen collected) on several occasions in February 2016, photographed (Fig. 24), and voice was recorded very near the location noted in Mills and Cohen (2015) at the remnants of the old governor's house 11.7544° N; 42.6517°E; elevation 1457 m. The individuals appeared similar to the Yellow-rumped Seedeater Crithagra xanthopygia (Rüppell, 1840) but had a lightyellow throat patch instead of white and other characteristics similar to those described by Mills and Cohen (2015). We observed a few individuals singing from the tops of trees (> 9 m) but they rarely came down below 3 m and none were captured even though the canopy net was within the flight path between perches. This fringillid (Crithagra sp.), with a faint yellowish throat, has been very well described by Mills and Cohen (2015). Edgar Mearns collected a series of Crithagra (formerly included in the genus Serinus) seedeaters from Ethiopia in 1912 during the Childs Frick Abyssinian Expedition and specimens are in the NMNH collections. Three of the specimens from that expedition (USNM 246634, 246635, 24658), collected near Sidamo or Bodessa, Ethiopia, are labeled as Reichenow's Seedeater Serinus reichenowi (now considered Crithagra reichenowi (Salvadori 1888)) but another specimen (USNM 246632), collected in Ethiopia (Gamo Gofa), Gato River near Gardula at 4000 feet [1220 m], was labeled by Mearns as Crithagra xanthopygia. Examination of this specimen did not reveal any significant characters to separate it from other specimens in the series and was presumably identified based on geographic location. All these previously collected specimens appear smaller overall in size than the birds observed in Day Forest. We only observed adult birds during our visit to Day Forest but Clement (2019) describes juveniles of Yellow-rumped Seedeater as sometimes having a yellowish throat patch, adding to the complexity of the identification of this species in the Day Forest. Yellow-rumped Seedeater is reported from Djibouti (Redman et al. 2011) and is thought to commonly occur in the Goda and Mahla mountains (Houssein Rayaleh pers. comm. 2019) whereas Reichenow's Seedeater is questionable in Djibouti (Redman et al. 2011). We agree with Mills and Cohen (2015) that it is impossible to assign the Djibouti birds to one taxon and further study of this species complex is needed to determine the taxonomic status of this seedeater in the Day Forest, or other locations in Djibouti.
Recently reported new avian records by Hering et al. (2015), Dove et al. (2017), and Buechley et al. (2019) indicate that more survey work is greatly needed throughout the country to document and describe the avifauna of Djibouti more thoroughly. While the avian surveys presented here are limited, they provide a glimpse of the biodiversity of Djibouti. Describing and documenting wildlife, including urban and invasive species of the country, will serve for better planning and development in the future.