Northern Bald Ibis breeding expansion: two new sites found in Morocco

By | 8 December 2017

The breeding of Northern Bald Ibis (Geronticus eremita) at the last viable wild colonies in southern Morocco during the last few years has been exceptional. The productivity ranged between 1 and 1.7 fledged chicks per breeding pair, and the overall population has been steadily increasing. However, this increase of population size is much slower than what we would expect from the high breeding output of the breeding pairs (even taking into account juvenile mortality). Importantly, it’s the number of breeding pairs that remained more or less stable (see table). So where the birds go?

The reason for the lack of significant increase of the breeding population is attributed to the dispersion of Northern Bald Ibises outside of their breeding areas located at Souss-Massa NP and Tamri cliffs (Oubrou & El Bekkay 2014). And we know that this dispersion is more often than not followed by something very interesting: breeding in the dispersion area. In this context, and already in 2015 when I first noticed this strange data (good breeding seasons but translated in slow increase of breeding population), I expected that the dispersing birds will establish new breeding colonies in the near future. And that’s exactly what happened.

The evolution of the breeding parameters of Northern Bald in Morocco during the period 2014-2016

Table showing the evolution during the last three years of the numbers of breeding pairs, fledglings and the total population size of the Northern Bald Ibis at the colonies of Souss-Massa National Park and Tamri cliffs combined.

New breeding colonies:

In spring 2017, Mohamed Aourir and his team discovered two breeding colonies with at least three confirmed active nests at two distinct coastal cliffs.

The first breeding site was discovered on the coastal cliffs north of Imsouane, at about 30 km north of the previously known colony of Tamri. Two active nests and a pair showing sexual behavior (copulation) were discovered at this site.

The second breeding site was found at about two kilometers north of the first one (c. 32 km from Tamri). An active nest and a pair for which the nest was not found (apparently non-nesting) were discovered here.

In addition to these confirmed breeding sites, the researchers found a flock of 11-15 Northern Bald Ibises at a roosting site located on the cliffs a few kilometers further north. However, they didn’t found any nest despite searching in the area.

This study provided evidence that Northern Bald Ibis is experiencing a breeding range expansion in Morocco. When these newly discovered colonies grow (and/or new colonies are found) and with the increase of the Spanish population, the species may soon be qualified to be downlisted from ‘Critically Endangered’ to ‘Endangered’. When this day arrive, it would be great. (Note that beside Morocco, I mentioned only the Spanish reintroduced population because the German/Austrian reintroduced population is still heavily managed, the Turkish population is semi-captive spending the winter in captivity instead of migrating to Africa, and the relict wild population in Syria is almost extinct).

Reference:

Aourir, M. Bousadik, H., El Bekkay, M., Oubrou, W., Znari, M. & Qninba, A. 2017. New breeding sites of the Critically Endangered Northern Bald Ibis Geronticus eremita on the Moroccan Atlantic Coast. Int J Avian & Wildlife Biol 2(3): 00021. PDF

References for the data presented in the table:

Oubrou, W. & El Bekkay, M. 2014. Rapport sur la reproduction de l’Ibis chauve dans la région de Souss-Massa, Saison 2014. Parc National de Souss-Massa, HCEFLCD. 7 pp

Oubrou, W. & El Bekkay, M. 2015. Rapport sur la saison de reproduction de l’Ibis chauve Geronticus eremita dans la région de Souss-Massa – 2015. Parc National de Souss-Massa, HCEFLCD. 8 pp

Oubrou, W. & El Bekkay, M. 2016. Rapport sur la saison de reproduction de l’Ibis chauve Geronticus eremita dans la région de Souss-Massa – 2016. Parc National de Souss-Massa, HCEFLCD. 7 pp

Northern Bald Ibis / Ibis chauve (Geronticus eremita), Souss-Massa National Park, Morocco (Lutz Dürselen)

Northern Bald Ibis / Ibis chauve (Geronticus eremita), Souss-Massa National Park, 29 Oct. 2017 (Lutz Dürselen).

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