The Warta Mouth National Park is a kingdom of birds, thus their protection and habitats conservation are the basic functions of our Park.
The floodlands of Warta River are of key importance for many birds species. The specific hydrological conditions and human economy (logging, melioration, mowing and pasturing) in the valley of Warta and its mouth section, influenced the formation of a mosaic of wetland habitats (the world of plants). As a consequence, in this area dwell characteristic bird groups. Depending on the season of the year, you can observe here breeding, migrating, wintering and molting species as well as those that appear here rarely. The Park’s bird record includes 270 species with 170 breeding ones.
A very crucial group are birds from Charadriiformes order. From few dozen of years we observe a decrease of their population in Poland and Europe. The main reason is a loss of habitats used while breeding as well as resting and feeding during migration. The state of conservation and regeneration of these habitats in Warta Mouth National Park makes it a vital place for these birds in Europe. Charadriiformes birds that regularly breed in Warta Mouth National Park are: Lapwing, Redshank, Snipe, Black-tailed Godwit, Curlew, Little Ringed Plover, Oystercatcher. The last one is an extremely sparse breeding bird in Poland. It is nesting mainly near the sea coast. In the inland it is even more rare, thus regular nesting of 5 pairs of this species in Warta Mouth National Park is a ornithological curiosity. An equally rare bird is Great Snipe, its breeding have not been evidently cofirmed, however some individuals may be observed during mating season and some while protecting their teritories. To the Charadriiformes order belong also gulls and terns which are quite numerously represented in the Park. Among the six tern species regularyly nesting in Poland five breed here: Black Tern, Whiskered Tern, White-winged Black Tern, Common Tern and Little Tern. Common and Little Terns nest on gravel roads and sandy hills, wherease Black, Whiskered and White-winged Black Terns nest in colonies located on floating plants and skins formed by dead vegetation. Among the gull species in the Park appear the nesting in colonies Black-headed Gulls and sparse Common, Herring, Little and Mediterranean Gulls which appear together with Black-headed Gulls.
Another group of birds bound with wetlands and nesting in Warta Mouth National Park are birds from Anseriformes order. Depending on the water level about 250-500 pairs of Greylag Geese nest in the Park. It is a only domestic, breeding goose species in Poland whose number is estimated at 2800 - 3000 pairs. The Mute Swan, being the biggest representative of the Anseriformes order, is a species easy to notice and observe. When the water level rises swans build their nests above the water surface, thus they are frequently very big constructions. The most abundant breeding species is Mallard. Some years are also good for Gadwall that is almost as numerous as Mallard. In the Park nest also Shovelers, Tufted Duck, Common Pochard, Common Goldeneye and rarely Common Teal, Pintail and Wigeon. A little known and very beautifully coloured bird belonging to the Anatidae order is Shelduck. In Poland nest from 120 to 140 pairs of Shelducks of which a maximum of 20 pairs in the Park. Equally beautiful is Goosander that nests in old hollow willows growing along Warta River.
Warta Mouth National Park is also a site for grebes i.e. Great Crested Grebe, Red-necked Grebe and Little Grebe, and especially for Black-necked Grebe, because 10% of all pairs nesting in Poland dwells here forming big colonies.
A very numerous bird is also Cormorant that concentrates in breeding colonies. Currently there are two colonies of about 500 nests in total in the Park. Close to Cormorants their nests build representatives of the Ciconiiformes order like: Grey Heron and rare Great White Egrets and Night Herons. Furthermore, in the Park nests Black Stork and its only nest is hidden in the alder swamp in Northern Polder. Sometimes in the Park appear Cattle Egret and Squacco Heron. In 1998, before forming Warta Mouth National Park, in “Słońsk” Reserve a probable nesting of Little Egret was affirmed so together with the brood recorded in 2003 in the valley of upper Vistula River these are the only cases when this species nested in Poland. In 1998 close to “Betonka” (“Bird’s Trail”) breeding of Black-winged Stilt was recorded, this species is a rarity in Poland. During the nights of May and June upon the wetland spread voices of Spotted Crake, Water Rail and Little Crake. In dryier parts of the Park in the Northern Polder you may hear voice of Corncrake that reaches a number up to 160 singing males.
The most abundant, about 10 pairs, species from the Falconiformes order in Warta Mouth National Park is the Marsh Harrier. It is a bird that is very well adapted to live in open-space meadows and different types of rushes. It builds its nest deep in the reeds and flies low over the meadows to hunt. While flying Marsh Harrier’s wings form the letter ‘V’. Species that build its nests on trees are: Buzzard, Red Kite, Black Kite, Honey Buzzard, Goshawk and Sparrowhawk. In the Falconidae family, there are species which do not build its own nests but use abandoned nests of crow birds like Hooded Crow or Raven, in the Park nest Kestrels and Hobbies. The biggest species from the Falconiformes order is White-tailed Eagle, that regarding its habitat preferences, constructs its nests more likely in big forest complexes north and south-east of the Park, thus this species is more numerous there. Three known sites of this species are located in the Park, but only one pair is successfully breeding and raises one nestling.
An especially abundant bird group appearing in the Park are warblers. Within this group the most attention arresting species are those which are rare or listed in the 1st attachement to Birds Directive, or these being an object of special attention of IUCN (International Union for Conservation of Nature), i.e species from the so called red lists. Examples of such species are Red-backed Shrike, Bluethroat, Barred Warbler, Bearded Tit. After few years of absence to its breeding grounds returned Aquatic Warbler, a small warbler which is globaly, i.e everywhere it appears (www.wodniczka.pl), endangered by extinction. Very interesting species that are worth mentioning are: wintering in India Scarlet Rosefinches, Great Grey Shrike which impales its food (small rodents, lizards) on thorns of bushes, building exceptional nests Penduline Tit, and beautifully singing Nightingale and Trush Nightingale.
In June and July among willow bushes, hide molting ducks, coots, greylag geese and swans and among high grasses flee flightless cranes which during molting season exchange simultaneously all flight feathers and lose for some time their flight ability. During migration season in summer, in the Park appear flocks with Wood Sandpiper, Spotted Redshank, Greenshank, Curlew and sandpipers. In ditches and on flooded meadows flocks of Black Storks hunt for fish.
Autumn is an especially crucial season when we can observe one of the most spectacular events in the live of birds, the autumn migration. These days are the most crowded time for the wetlands of Warta Mouth National Park. Especially picturesque are crane flocks landing with shriek at sunset (up to 7 000 individuals). A more sensitive ear may catch the characteristic squeaky voice of young cranes. The gathering cranes are acompanied by geese flocks which also want to spend a save night in the Park. The number of geese simultaneously spending night in the Park is between 70 000 - 90 000 and sometimes even 150 000, sumpremely 200 000. In these huge flocks appeare also Pink-footed and Lesser White-fronted Geese as well as Barnacle Geese, Brent Geese, Red-breasted Geese and Canada Geese. Besides geese in the Park appear few species of ducks, coots and swans forming a flock of almost 250 0000 individuals. This birds abundance arrests attention of White-tailed Eagles groups of which are easy to observe in autumn and winter.
With the begining of winter from the far north come Whooper Swans. Yearly, in Warta Mouth National Park winters up to 3 000 individuals and it is one of the biggest clusters of Whooper Swans in Europe. On the dry meadows of Northern Polder winter Rough-legged Buzzards which while hunting hang in the air for a moment and look out for a prey. In this part of the Park appear also Hen Harriers and Merlins, but the night belongs to Long-eared Owl, Barn Owl and Short-eared Owl.