Is-Simar is less than 5ha in area. Despite its small size, the wetland supports a variety of birds throughout the seasons. Due to Malta’s position along the narrow Central Mediterranean bird migration route, most turn up in Spring and Autumn, though their stays are usually short.
This is evident at Is-Simar too, with birds from barn swallows to great white egrets dropping in for a snack and a rest. Wagtails and hirundines often roost in large numbers, in the thick reed bed that grows at the site.
The reed beds are also important foraging and potential nesting sites for summer visitors, like the reed warbler and the little bittern. Also, for year-round residents, like the moorhen and the little grebe. Wintering birds, on the other hand, include the water rail and the common coot.