Matsalu National Park (previously Matsalu Nature Reserve, , often just Matsalu) is a nature reserve and national park situated in Lääne and Pärnu Counties, Estonia. Matsalu National Park spans an area of , comprising Matsalu Bay, the Kasari River delta, the village of Matsalu and surrounding areas. Matsalu Bay is one of the most important wetland bird areas in Europe, due to its prime position on the East Atlantic Flyway. Large numbers of migratory birds use Matsalu as a staging area. Every spring over two million waterfowl pass Matsalu, of which around 1.6 million are long-tailed ducks. Matsalu National Park is a home for a number of endangered species, many of which are listed in the Estonian IUCN Red List, including the white-tailed eagle of the highest conservation category, a lot of bird species of the second and third protection categories, 22 strongly protected plant species, the natterjack toad, and ten species of mammals of the second conservation category. Description Matsalu National Park covers a total area of , encompassing Matsalu Bay along with the delta of the Kasari River and its surrounding areas — floodplains, coastal meadows, reedbeds, woodlands, wooded meadows, and the section of Väinameri around the mouth of the bay, which includes more than 50 islands. of the protected area is terrestrial and is aquatic. Matsalu Bay is shallow, brackish and rich in nutrients. The bay is long and wide, but has an average depth of only and a maximum depth of . Water salinity is approximately 0.7 per mil. Shoreline length of the bay is about . The bay's shoreline lacks high banks and is populated mostly with shingle shores, with muddy and overgrown reed in the innermost, sheltered part of the bay. Kasari River is the biggest of several rivers that run into Matsalu Bay. The delta of the Kasari River is not in its natural condition due to dredging between 1930 and 1960; the alluvial meadow of the delta (), most of which is actively managed, is one of the biggest open wet meadows in Europe. Reeds and rushes surrounding the main channel expand westwards up to every year. Annual inflow into the Matsalu Bay from the Kasari River exceeds the volume of the bay itself approximately eight times; average seasonal variation of the Kasari River exceeds . The rivers carry large quantities of nutrient-rich sediments into the bay from an over drainage basin.