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Habitats

Breeding Sites

During the breeding season the NBI can be found on semi-arid and rocky plains, in close proximity (less than 15-20 km) to cultivated land, steppe and meadows which it uses to forage. It is a colonial breeder and the nests of loosely constructed twigs and vegetation are placed on cliff ledges at least one-metre-wide which may be sea or large river cliffs and occasionally, even large buildings. It will also use artificial ledges. The height, size and shape of the ledges are all important in terms of safety from predators and other disturbance and also the aspect and the amount of shade provided (Pegoraro 1996). Morocco: the remaining population exclusively uses sea cliffs (Bowden et al. 2003). Syria: birds use limestone rock faces (Serra et al. 2009) – all of which are extremely difficult for humans to access. Turkey: the semi-wild population occupies mainly artificial nest boxes as well as some provided rock platforms and a small minority nests on natural rock faces and caverns.

Feeding Sites

The diet of the Northern Bald Ibis includes any available animal life including insects, spiders, scorpions, earthworms, snails and vertebrates such as fish, amphibians, lizards and snakes (Aghnaj et al. 2001, Serra et al. 2008), and even occasional small rodents and birds. It will also feed on vegetation including berries, shoots, duckweed, and rhizomes of aquatic plants (Hancock et al. 1992).

The altitude of the feeding areas increases through the season from spring to the summer months (Serra et al. 2008). The substrate of feeding areas varies enormously between soft mobile sand, through a full range of other substrates to almost entirely rocky areas if there is a temporary abundance of prey in the area, but these are all open terrain areas.

The birds need sufficient visibility to avoid approaching predators and also sufficiently open spaces to allow their characteristic (often fast walking) foraging style, which is mainly tactile by probing within soft substrate, preferably soil and sand. But they are also able to hunt using optical cues on and above the substrate surface.

During the breeding season it is important that the vegetation is either sparse and open (semi-arid areas) or not taller than 10 to 15 cm (meadows and pasture). Changes in vegetation structure and in cultivation may lead to quick abandonment of feeding areas and nesting grounds (Hirsch pers. comm.) Little is known about the use of habitats whilst birds are on migration, although satellite tracking and surveys in the field have shown that, in addition to open arid habitats, they also use recent or active cultivations (Serra et al. 2010), and GPS data from European birds indicate that they use similar habitats as in the breeding season i.e. mainly meadows and pastures with low vegetation.

Morocco: primarily littoral steppe, fallow areas of cultivation, and occasionally active but un-intensively cultivated areas. Feeding areas during the breeding season in Morocco were always within 26 km of the nesting sites, but most areas were less than half that distance (Bowden et al. 2003).

Syria: not dissimilar to feeding sites in Morocco, but somewhat inferior, usually in undulating and degraded steppe with sparse dwarf shrubland within a large drainage basin of mountain ranges (providing sheer cliffs for nesting). Probably due to the advanced degree of degradation of the original feeding habitats, birds rely on temporary abundance of young toads living in human-made artificial reservoirs (Serra et al. 2008).

Central Europe: free-flying birds almost exclusively use meadows and pastures as feeding areas (Fritz & Unsöld 2011).

Turkey: the semi-wild population frequently forages in the surrounding areas despite the food provisioning there. Areas used include a large tree nursery, agricultural fields, margins of the Euphrates River and areas of grassland steppe.

Winter Sites

Western

In the main Moroccan breeding areas, the winter distribution is largely similar to that during the breeding season. There are some seasonal variations and areas of littoral steppe still within the Souss-Massa National Park, which are used more extensively outside the breeding season, as are some otherwise more heavily disturbed and unprotected areas north of Agadir.

Eastern

Satellite tracking has uncovered the main wintering grounds and the majority of the relict population has consistently returned to a very restricted area in highland Ethiopia. The birds utilise wet and dry pastures, including recently cut hayfields, in an area where human disturbance is low, but it is also notable that there is no evidence of any hunting pressures. Repeated visits have shown that the birds consistently use the same areas (mostly just 9 km2) and utilise tall trees for roosting (Serra et al. 2013).