Brood parasitism: the first nest of the Eurasian Oystercatcher in Lazio (Italy) could be an example

During the 2025 monitoring of the Kentish Plover, Anarhynchus alexandrinus, population nesting along the Lazio coast, a nest of a Eurasian Oystercatcher, Haematopus ostralegus, was found. The first egg was laid on April 30 on a sandy beach with limited and partly forbidden access. This is the first time that the species has nested in Lazio and it also represents the southernmost nesting site in Italy and one of the rare egg-layings along the Tyrrhenian coast. To lay its eggs, the Oystercatcher used an active nest of a Kentish Plover pair from which two eggs were removed. The cause is probably because the male Oystercatcher had a left tarsus without toes, and this may have prevented it from digging in the sand. The eggs were incubated for 24 days and then probably preyed upon by a Canidae. In addition to the Oystercatcher, the Little Ringed Plover, Charadrius dubius, and the Kentish Plover were found nesting in the same stretch of beach a few dozen meters away. Eggshells, found near the nest, were collected and used to determine some heavy metals such as chromium, nickel, mercury, manganese, and zinc.

Arcamone E., Meschini E. & Tartarelli G., 2024 – Accertata nidificazione di Beccaccia di mare Haematopus ostralegus nell’Italia peninsulare. Picus, 50: 37-40.

Ardamatskaya T. B., 2000 – Repeated nesting of the oystercatcher in the great cormorant’s nest. In Birds of the Azov-black Sea region at border of the millennium. Proc. of conference proceedings. Odesa: AstroPrint.

Arrigoni degli Oddi E., 1926 – Ornitologia italiana. Turin: Hoepli.

Barwisch I., Mewes W., Schmitz Ornés S. & Guenther S., 2024 – Heavy metal residues in eggshells of Common Cranes (Grus grus) nesting in an agricultural region in north-eastern Germany. Journal of Ornithology, 165: 507-520. DOI: https://doi.org/10.1007/s10336-023-02122-3

Battisti C., Perchinelli M., Luiselli L., Dendi D. & Vanadia S., 2022 – Cages mitigate predation on eggs of threatened shorebirds: a manipulative-control study. Conservation, 2: 450-456. DOI: https://doi.org/10.3390/conservation2030030

Becker P. H., Furness R. W. & Tasker M. L., 2003 – Seabirds as monitors of marine pollution. In: Seabirds as monitors of the marine environment. Furness R. W., Tasker M. L. (eds.). ICES Cooperative Res. 258: 3-25.

BirdLife International, 2017 – European birds of conservation concern: populations, trends and national responsibilities. Cambridge: BirdLife International.

Brichetti P. & Fracasso G., 2015 – Checklist degli uccelli italiani aggiornata al 2014. Rivista Italiana di Ornitologia, 85: 31-50. DOI: https://doi.org/10.4081/rio.2015.264

Brichetti P. & Fracasso G., 2018 – The birds of Italy. Volume I. Anatidae-Alcidae. Latina: Edizioni Belvedere.

Brunelli M., Fraticelli F. & Molajoli R. 2019 – Checklist degli uccelli del Lazio aggiornata al 2019. Alula, 26: 39-40.

Burger J., 1994 – Heavy metals in avian eggshells: another excretion method. Journal of Toxicology and Environmental Health, 41: 207-220. DOI: https://doi.org/10.1080/15287399409531837

Caterini F., 1932 – Nidificazione del Cavaliere d’Italia (Himantopus candidus L.) e della Beccaccia di mare (Haematopus ostralegus L.) presso Pisa. Rivista Italiana di Ornitologia, 2: 47-50.

Cramp S. & Simmons K. E. L., 1983 – Handbook of the Birds of Europe the Middle East and North Africa. The Birds of the Western Palearctic. Volume III, Waders to Gulls. Oxford: Oxford University Press.

Dittmann T., Becker P. H., Bakker J. & Bignert A., Nyberg E., Pereira M. G., Pijanowska U., Shore R., Stienen E. W. M., Toft G. O. & Marencic H., 2011 – The EcoQO on mercury and organohalogens in coastal bird eggs: report on the pilot study 2008 – 2010. (INBO.R.2011.43). Bruxelles: Research Institute for Nature and Forest.

Ens B. J. & Underhill L. G., 2014 – Synthesis of Oystercatcher conservation assessments: general lessons and recommendations. International Wader Studies, 20: 5-22.

Felici F., Prosdocimi M., Sabbatini M., Pascucci M. & Giacchini P., 2024 – Prima nidificazione di Beccaccia di mare Haematopus ostralegus nella regione Marche (Porto Ancona). Alula, 31: 69-72.

Grattini N. & Mantovani C., 2019 – Prima nidificazione di Beccaccia di mare Haematopus ostralegus nella Pianura Padana interna (provincia di Mantova, Lombardia). Rivista Italiana di Ornitologia, 89: 47-48. DOI: https://doi.org/10.4081/rio.2019.457

Ma Y., Choi C. Y., Thomas A. & Gibson L., 2022 – Review of contaminant levels and effects in shorebirds: Knowledge gaps and conservation priorities. Ecotoxicology and Environmental Safety, 242: 113868. DOI: https://doi.org/10.1016/j.ecoenv.2022.113868

McDonald M. A. & Bolton M., 2008 – Predation on wader nests in Europe. Ibis, 150: 54-73. DOI: https://doi.org/10.1111/j.1474-919X.2008.00869.x

Ninni E., 1938 – Gli uccelli delle lagune venete. Roma: Atti XXVI Riunione della Società Italiana per il Progresso delle Scienze; pp. 1-32.

Pietrelli L. & Biondi M., 2009 – Notes on Little Egret breeding biology and on mercury content in eggshells and feathers. Rendiconti Lincei Scienze Fisiche e Naturali, 20: 219-224. DOI: https://doi.org/10.1007/s12210-009-0050-z

Scarton F., 2022 – Beccaccia di mare: 198-199. In: Lardelli R., Bogliani G., Brichetti P., Caprio E., Celada C., Conca G., Fraticelli F., Gustin M., Janni O., Pedrini P., Puglisi L., Rubolini D., Ruggieri L., Spina F., Tinarelli R., Calvi G., Brambilla M. (eds.). Atlante degli uccelli nidificanti in Italia. Latina: Edizioni Belvedere.

Scarton F. & Valle R., 1994 – Nesting parameters of Oystercatchers, Haematopus ostralegus, in the Po Delta (Italy). Le Gerfaut, 84: 3-6.

Scarton F. & Valle R., 1996 – La Beccaccia di mare, Haematopus ostralegus, torna a nidificare in laguna veneta. Rivista Italiana di Ornitologia, 66: 202-203.

Simonetti P., Botté S. E. & Marcovecchio E., 2015 – Exceptionally high Cd levels and other trace elements in eggshells of American Oystercatcher (Haematopus palliatus) from the Bahía Blanca Estuary, Argentina. Marine Pollution Bulletin 100: 495-500. DOI: https://doi.org/10.1016/j.marpolbul.2015.09.006

Valle R. & Scarton F., 1996 – Nest-site selection and interspecific relationship of Oystercatchers Hae- matopus ostralegus on the Adriatic coast of Italy. Vogelwelt, 117: 75-81.

Valle R. & Scarton F., 1999 – Habitat selection and nesting association in four species of Charadriiformes in the Po Delta (Italy). Ardeola, 46: 1-12.

Valle R. G. & Scarton F., 2019 – Effectiveness, efficiency, and safety of censusing Eurasian Oystercatchers Haematopus ostralegus by unmanned aircraft. Marine Ornithology, 47: 81-87. DOI: https://doi.org/10.5038/2074-1235.47.1.1296

van de Pol M., Vindenes Y., Saether B.E., Engen S., Ens B. J., Oosterbeek K. & Tinbergen M., 2010 – Climate change and variability on population dynamics in a long-lived shorebird. Ecology, 91: 1192-1204. DOI: https://doi.org/10.1890/09-0410.1

van de Pol M., Atkinson P., Blew J., Crowe O., Delany S., Duriez O., Ens B. J., Hälterlein B., Hötker H., Laursen K., Oosterbeek K., Petersen A., Thorup O., Tjørve K., Triplet P. & Yésou P., 2014 – A global assessment of the conservation status of the nominate subspecies of Eurasian Oystercatcher Haematopus ostralegus ostralegus. International Wader Studies, 20: 47-61.