The Leschenault Estuary and its range of tidal habitats attract a diversity of waterfowl and other bird species. It is an important part of the network of wetlands used by waterbirds in the south-west of Western Australia. Migratory birds travel half way around the world to use the estuary. Surveys in the 1980s to 1990s identified more than 60 bird species, of which 18 species were JAMBA-listed (Japan-Australia Migratory Bird Agreement) and CAMBA-listed (China-Australia Migratory Bird Agreement) birds. The Leschenault Peninsula National Park surrounding the estuary on its west side is the bird’s main wetland habitat and can host up to 5000 birds at any one time.
The surveys identified that waterbirds used the estuary and fringing wetlands in different ways. The open water habitats were mainly used for feeding by the larger species of birds. The fringing habitats supported a greater density and diversity of birds, which use the areas for feeding, roosting and breeding. In the hot summer months, freshwater seeps along the peninsula are thought to be a strong attraction for birds. This specificity of habitat use highlights the importance of preserving the different foreshore habitats and outlying wetlands around the estuary.
Activities which affect bird life include:
- Reclamation – loss of habitat and reduced nesting and feeding areas.
- Dredging –reduces feeding grounds for birds which feed on plants, invertebrates and fish. Increases in turbidity makes it difficult for birds that fish by sight.
- Mosquito control – can introduce toxins into the food chain. Insect larvae and crustaceans (food for birds) are killed by pesticides.
- Boating – causes a disturbance to birds, which may be displaced to quieter areas.
- Public access to foreshores — litter can cause physical injury and death to birds through entanglement or consumption. Human activities such as digging for bait, fishing or walking can disturb birds using the habitats.