A study published last July in the journal Animal Conservation provides the very first national-scale estimate of the breeding population size of the Marbled Teal (Marmaronetta angustirostris) in Morocco, also known as the Marbled duck.
Conducted by a team bringing together Tour du Valat, École Pratique des Hautes Études, GREPOM/BirdLife Morocco, the Faculty of Sciences Ben M’sik in Casablanca and BioSphère Environnement, this research fills a gap that had previously made it difficult to reliably assess the species’ status in the country and, consequently, to effectively plan its conservation.
A threatened nomadic species
The Marbled Teal is classified as globally threatened and vulnerable in Europe by the IUCN. Unlike most waterfowl, it does not follow a typical migratory pattern: its often erratic movements follow water availability in temporary wetlands, making it particularly difficult to monitor and count.
A large-scale field monitoring protocol
Launched in 2023, this national monitoring programme is based on a two-stage random sampling design: 35 primary units of 100 km², within which 187 secondary sampling units of 0.25 km² are nested, covering the entire Moroccan territory from the mouth of the Moulouya River in the north to the Saharan wadis in the south. The objective was to estimate the size of the Marbled Teal breeding population and identify key breeding habitat features.
A national Marbled Teal population estimated at 386 broods
At the scale of the sampled sites, covering 46.75 km² of wetlands, the best model estimated a total of 24 broods, with an average detection probability of 0.71, highlighting the need to account for imperfect detection in field surveys. Extrapolated to all Moroccan wetlands (748 km²), this estimate corresponds to a national breeding population of 386 broods. The field data were analysed using models designed to correct for biases associated with the species’ imperfect detectability. These results provide the first robust national-scale estimate of Marbled duck breeding population size in Morocco.
Emergent vegetation and wetland type, particularly ponds, emerged as the main predictors of brood abundance at a site — a valuable lead for guiding future habitat-focused conservation actions.
A new monitoring protocol adaptable to other contexts
Beyond this reference figure, the authors propose a monitoring and modelling protocol that can be applied to other species and other regions, helping to sustainably improve the monitoring and conservation of threatened waterbird species in North Africa.
Publication reference
📄 Bouchri, H., El Hamoumi, R., Musseau, R., Béchet, A. & Champagnon, J. (2026). Using Two-Stage Random Sampling and N-Mixture Models to Estimate the Breeding Population Size of a Threatened Nomadic Species in Morocco. Animal Conservation. https://doi.org/10.1111/acv.70087