On 20 October 2021, four (4) heads of Common shelducks (Tadorna tadorna) were spotted in the mudflats of Tanza Marine Tree Park located in Tanza, Navotas during the regular monitoring of the Conservation and Development Division of DENR - National Capital Region.
Common shelducks are short-billed ducks with a goose-like appearance. They feed mostly on small invertebrates like snails, molluscs, crustaceans, insects and, sometimes, on small plant particles. Common shelducks are known to breed in Central Asia and East Siberia and winter in East Asia. This rare migrant has only been recorded a few times in the Philippines.
The Philippines is part of the East Asian-Australasian Flyway that serves as a staging site or a stopover area for over 500,000 migratory waterbirds annually. Birds migrating southwards arrive in the Philippines by around September with peak arrivals in January of the following year. These waterbirds temporarily congregate in coastal and inland wetlands (e.g. rivers, lakes, ponds, swamps, and marshes) in the country to feed and refuel as they continue their southward migration, crossing large ecological barriers like oceans, deserts, rivers, and mountains.
Tanza Marine Tree Park is a 26-hectare mangrove park, which is among the over 300 known migratory bird sites in the country. The occurrence of the Common shelduck in the park, among other threatened waterbirds, such as Chinese egret (Egretta eulophotes), Black-tailed godwit (Limosa limosa), Far eastern curlew (Numenius madagascariensis), and Great knot (Calidris tenuirostris) highlights the significance of the continuous protection of the area, which is among the few remaining mangroves and migratory bird habitats in Metro Manila.
Common shelducks and other migratory bird species are part of the country’s rich biodiversity. These waterbirds maintain the diversity of other organisms, control pests, and serve as bioindicators of wetland health. By protecting wetlands, the global connectivity of habitats used by migratory birds throughout their natural range is maintained, allowing them to complete their migration cycle.