L’Anatra marmorizzata Marmaronetta angustirostris nidifica in Sardegna

Nell’estate del 2013 è stata riscontrata la prima nidificazione di Anatra marmorizzata in Sardegna. L’evento è particolarmente interessante in quanto la specie, oltre ad essere considerata minacciata a livello globale da BirdLife International, in Italia nidifica solo in Sicilia con singole coppie.

La notizia è stata ufficializzata sulla rivista British Birds (Podda & Grussu 2014 – Marbled Ducks breeding in Sardinia and Sicily – British Birds 107: 485-488); la località di nidificazione, per motivi evidenti, è stata mantenuta segreta. Di seguito alleghiamo il testo della nota, pubblicata di recente. Un articolo più approfondito e con un maggior numero di fotografie è in preparazione da parte degli stessi AA. per il prossimo Aves Ichnusae.


British Birds 107 • August 2014 • 485– 488

Marbled Ducks breeding in Sardinia and Sicily
Massimiliano Podda & Marcello Grussu

The Marbled Duck Marmaronetta angustirostris is classified as ‘Vulnerable’ by the IUCN. Four separate biogeographical populations have been identified; the west Mediterranean population breeds in Morocco, Algeria, Tunisia and Spain and is believed to winter in North Africa and sub-Saharan West Africa. Largely because of extensive habitat loss, but also fluctuating patterns of rainfall and water levels in wetland areas, the population declined throughout much of the twentieth century, although the last 20 years or so have seen some recovery. In Spain, for example, the population declined from several thousand pairs at the end of the nineteenth century to 30–40 pairs in 1994 (BirdLife International 2004), recovering to 96 pairs in 2007, with a handful of pairs now breeding in the Balearics and 30–200 pairs in the Canary Islands during 1994–2001 (Martí & del Moral 2003; GOB 2010). However, this apparent increase in the west Mediterranean population may reflect improved awareness and observer coverage rather than a true increase (www.birdlife.org). The Marbled Duck has always been a rare and irregular visitor to Italy. The species may have bred occasionally in the past, although there is no confirmed evidence. For example, about 50 documented records in the nineteenth century included a group of c. 70 in June–August 1892 on Lago di Massacciucoli near Lucca, Tuscany, which led Giglioli (1907) to suspect that breeding had occurred. There were just 20 records of Marbled Duck in Italy in the twentieth century but, since 2000, breeding has occurred in Sicily, the first confirmed breeding records for Italy. This note documents a further breeding record, from Sardinia in 2013.

Breeding in Sardinia
On 5th May 2013, MP discovered a pair of Marbled Ducks on a wetland in southwestern Sardinia. The site was visited regularly after that and on 30th June a female and 14 ducklings (judged to be about one week old) were seen (Plate 01). Fourteen young were still present on 10th July, but the brood had declined to ten on 4th August, while at least four and possibly six young were present on 19th August. The wetland concerned is rich with emergent vegetation, including Phragmites australis, Thypa, Juncus, Carex, similar to the breeding sites elsewhere in the species’ range (Green 1996). Since the incubation period is approximately 25–27 days (BWP), the first observation suggests that the clutch was completed around 28th May, followed by hatching on or about 23rd June. In Spain, broods have been recorded between mid April and mid September, with a mean hatch date of 20th June (Green 1996). There are about ten historical records of Marbled Duck in Sardinia, two in the twentieth century (Grussu 2001; Brichetti & Fracasso 2003), an adult bird near Portoscuso, Cagliari, on 27th May 2007 and then up to three birds present in wetlands near Portoscuso from 26th August to 3rd October 2012 (MP and MG pers. obs., Roberta Corsi pers. comm.). Clearly, the habitat conditions in southwest Sardinia are currently suitable for breeding and, if these can be maintained, it is hoped that further breeding will occur. The species is fairly numerous in North Africa (several thousand were recently discovered in Algeria and Tunisia; www.birdlife.org), and this is probably the source of the recent records in Sardinia.

Breeding in Sicily
In 2000, five adults, including one pair with eight chicks, were found in the Trapani region of western Sicily (Sciabica 2002). Subsequently, 1–2 pairs have occasionally nested at this site, while 1–3 pairs have bred irregularly in southeastern Sicily (Corso 2005; Ruggieri & Sighele 2007; Ruggieri & Nicoli 2009; Nicoli et al. 2011). There were six records (of 1–15 birds) in Sicily in 2012 but breeding was not established in that year. It appears that the status of Marbled Duck in Sicily is slowly changing from that of a vagrant and occasional breeder; most records are in the period from April to September, but it remains rare in winter (Corso 2005; Nicoli et al. 2013).

Plate 01 - Adult Marbled Duck Marmaronetta angustirostris with 14 ducklings (approximately seven days old), Sardinia, June 2013. The first breeding record of this species in Sardinia (Massimiliano Podda).

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Grussu, M. 2001. Checklist of the birds of Sardinia. Updated to December 2001. Aves Ichnusae 4: 2–55.
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–– & Nicoli, A. (eds.). 2009. Annuario 2008. EBN Italia, Verona.
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Massimiliano Podda, maxpodda@lanaturadelsulcis.it
Marcello Grussu, porphyrio@tiscali.it