BIRDWALKERMONDAY

Wednesday, 10 November 2021

3-11-2021 BIOPARC, VALENCIA - ADDAX (MALE - SUMMER COAT) (Addax nasomaculatus)

The addax (Addax nasomaculatus), also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus Addax, it was first described scientifically by Henri de Blainville in 1816. As suggested by its alternative name, the pale antelope has long, twisted horns – typically 55 to 80 cm (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males. Males stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). They are sexually dimorphic, as the females are smaller than the males. The colour of the coat depends on the season – in the winter, it is greyish-brown with white hindquarters and legs, and long, brown hair on the head, neck, and shoulders; in the summer, the coat turns almost completely white or sandy blonde.

The addax inhabits arid regions, semideserts and sandy and stony deserts. It even occurs in extremely arid areas, with less than 100 mm annual rainfall. It also inhabits deserts with tussock grasses (Stipagrostis species) and succulent thorn scrub Cornulaca. Formerly, the addax was widespread in the Sahelo-Saharan region of Africa, west of the Nile Valley and all countries sharing the Sahara Desert; but today the only known self-sustaining population is present in the Termit Massif Reserve (Niger). However, there are reports of sightings from the eastern Air Mountains (Niger) and Bodélé (Chad). Rare nomads may be seen in northern Niger, southern Algeria and Libya; and the addax is rumoured to be present along the Mali/Mauritania border, though there have been no confirmed sightings. The addax was once abundant in North Africa, native to Chad, Mauritania and Niger. It is extinct in Algeria, Egypt, Libya, Sudan and the Western Sahara. It has been reintroduced into Morocco and Tunisia.

3-11-2021 BIOPARC, VALENCIA - PIN TAILED SANDGROUSE (Pterocles alchata)

The pin-tailed sandgrouse (Pterocles alchata) is a medium large bird in the sandgrouse family. It has a small, pigeon-like head and neck and a sturdy, compact body. It has long pointed wings, which are white underneath, a long tail and a fast direct flight. Flocks fly to watering holes at dawn. The call is a loud kattar-kattar. This gregarious species breeds on dry open treeless plains and similar habitats. Its nest is a ground scrape into which two or three cream-coloured eggs with cryptic markings are laid. Both sexes incubate the eggs.

The pin-tailed sandgrouse is about 35 centimetres (14 in) long. Its head and upperparts are yellowish-green. The underparts are white with a chestnut breast band separating the belly from the green neck. Sexes are somewhat similar, but the female is better camouflaged and has a shorter tail than the male. There are two subspecies; P. a. alchata breeds in southern Europe and P. a. caudacutus breeds in northwestern Africa, the Middle East and southeastern Asia. It is a partial migrant, with some Asian birds moving to the Middle East and northern Pakistan in winter. Males of the eastern race have duller underparts than the European birds, and the females have white, rather than yellow, wing coverts.The pin-tailed sandgrouse is a robust, medium-sized bird about 31 to 39 centimetres (12 to 15 in) in length. The general colouring is cryptic, a blend of barred and flecked olive green, brown, buff, yellow, grey and black. The underparts and the feathered legs are dull white.

The sexes are different and the male's plumage varies with the time of year. In the breeding season, the male has the crown, most of the neck, the back and under-wing coverts a yellowish-green colour with dull yellow spots in the shoulder region. The cheeks are also yellow with a narrow black line extending from the beak, through the eye to the nape of the neck. The irises are brown and the beak is slatey grey. There is a black patch on the throat immediately below the beak and below this, there is a broad, reddish-brown band round the breast, bordered by a thin black stripe above and below the band. The outer wing coverts are chestnut edged with black and white and the primaries are black with pale edges which gives both the leading and trailing edges of the wing the appearance of a black rim in flight. The rump and the tail are distinctly barred in black and brownish-yellow and the streamers on the central tail feathers are slate-grey. Outside the breeding season, all the upper parts, including the crown and cheeks, are barred in black and brownish-yellow and the throat loses its black patch, becoming whitish.

The female is generally similar to the male but the colours are duller. The cheeks and neck are golden-buff and lack the greenish tinge of the male. There is a black stripe running through the eye. The chin is white and there is an additional yellow-buff band across the breast with a broad black stripe above, another thinner one about a third of the way down and a further narrow black stripe at the base. The back and wings are grey, barred with black. The rump and the tail (which has shorter central feathers than the male) are similar in colouration to the male but have finer black barrings.

In flight, the pin-tailed sandgrouse can be identified by its bright, white underparts and under-wing coverts, and the long feathers in the centre part of its tail. It is usually silent when on the ground but in the air communicates with other birds with a frequently uttered, loud "kattar-kattar", a nasal "ga-ga-ga" and a low-pitched "gang gang".

The pin-tailed sandgrouse breeds in North Africa and the Middle East, Turkey, Iran, Iraq and Kazakhstan. In Europe it breeds in Spain, Portugal and the southern part of France. Eastern populations, particularly those from Kazakhstan, migrate to Pakistan and parts of northern India in winter.

The pin-tailed sandgrouse inhabits open areas of stony land, semi arid areas at the edge of deserts, treeless plains and occasionally dried-out mud flats. In winter it may visit ploughed or fallow land but prefers sandy soils and is much less reliant on vegetation cover than the black-bellied sandgrouse (Pterocles orientalis) which has a similar range. It does not occur at elevations above about 1,000 metres (3,300 ft).