Ecological importance of middle intertidal mudflats for shorebirds on the west coast of Peninsular Malaysia

The west coast of Peninsular Malaysia, within the East Asian–Australasian Flyway, is an important stopover site for migratory and passage shorebirds to refuel for their long journeys by taking advantage of seasonal fluctuations in food availability. Coastal areas, particularly intertidal zones and mudflats, are vital foraging grounds for shorebirds. However, their specific patterns of mudflat use along the west coast of Peninsular Malaysia remain poorly understood. This study examined the habitat preferences and foraging patterns of shorebirds in different intertidal mudflat zones by focusing on two coastal Important Bird and Biodiversity Areas – the North-Central Selangor Coast and Teluk Air Tawar-Kuala Muda Coast. The middle zone supported a high abundance of foraging shorebirds, suggesting a preference for this zone due to its optimal combination of intertidal areas, mudflats, and shallow water zones, being neither submerged for too long nor exposed to the sun for extended periods, and providing an optimal environment for invertebrates. Shorebirds were classified into spatial specialist, partial specialist, and generalist species, with five species specialising in the lower, middle, or upper mudflat zone. Some shorebird species, such as the Eurasian Curlew (Numenius arquata) and Ruddy Turnstone (Arenaria interpres), are considered tidal followers, as their ecological patterns were significantly influenced by the tidal cycle. The observed shorebird populations' preference for middle tidal flats, along with the presence of endangered species, such as Nordmann's Greenshank (Tringa guttifer), in this zone, highlights the critical importance of conserving mudflat habitats, particularly middle tidal flats, and underscore the need for detailed ecological insights in conservation planning.