An Ornithological Sketch of the Barycz Valley in Poland by A

An ornithological sketch of the Barycz valley in Poland By A. Mrugasiewic^ and J. WitkowsM Zoological Institute, University of Wroclaw (Plates 50-57) INTRODUCTION THE BARYCZ VALLEY, in western Poland, has long been famous for its birds. It is one of the few places in central Europe where such rare species as White-tailed Eagle, Lesser Spotted Eagle, Kite, Grey Lag Goose, Crane, Black Stork, Purple Heron* and others are con centrated in a relatively small area, and, equally important, it forms a reserve of major importance for nesting and passage duck of many kinds. The Barycz, a tributary of the Oder in the northern part of Lower Silesia, is a small lowland river, some 100 miles (162 km.) long; its fall is insignificant, amounting to no more than 12.5 inches per mile (22 cm. per km.) in its middle and lower reaches. It has many tribu taries, rills and rivulets in a large fluvo-glacial valley. The valley itself is bounded by the Trzebnickie hills on the south, while in the north it passes gradually into the Wielkopolsko-Kujawska plain. It is widest, up to 16 miles (25 km.), in the Milicz district. In the glacial period a great river flowed here in front of a thawing glacier. Since the beginning of the 14th century, the area has been noted as a centre for the large-scale production of Carp (Cyprinus carpio). The flat, gently sloping terrain enabled large areas to be covered with artificial ponds at small cost for the breeding of fish. In the Middle Ages, this was carried on by monks, mainly Cistercians, and by the middle of the 17th century the total area of the ponds had reached 20,863 acres (8,443 hectares), but later a number were drained and converted into agricultural land, the mud providing a fertile sediment some 16 inches (40 cm.) thick. The present area of the fish ponds is 16,113 acres (6,521 hectares) and the production of Carp in recent years has varied between 1,237 aQd *>386 tons (between 1,258 and 1,408 metric tons). Since the war, a valuable series of national parks and nature reserves has been built up in Poland, and a considerable area in the Barycz valley has been designated as a bird reserve (the "Wood- and-Pond" Reserve), with shooting under rigorous control. This has led to the nesting of a number of rare species, in some cases after an interval of many years, and increases in the breeding populations of 'Scientific names are all given in Appendices A and B on pages 268-272, as well as in the tables. 245 ZMIGROD DALE FIG. I . Map of the Barycz valley, Poland, the boundaries coinciding with those of the former administrative district of Milicz and the groups of ponds being indicated by numbers: i Radzia_dz, 2 Ruda Sulowska, 3 Milicz, 4 Krosnice and 5 Potasznia (see page 249) (drawn by Robert Gillmor from a sketch by the authors) 246 MILICZ DALE boundary of area woods rivers, canals, etc. narrow-gauge railway main roads ponds other important roads 247 BRITISH BIRDS others, despite the fact that this fertile valley has a not inconsiderable human population. The area has long been of interest to ornithologists, both Polish and German. It was first "discovered" ornithologically and described by Floericke (1891). Among pre-war observers, three deserve particular mention, F. Pampel, F. Pax and A. Schlott. Pampel (1922) listed as many as 172 species of birds in the Barycz valley. After the war, Szarski (1950) was the first to publish a list of the region; it included 130 species, of which 118 were breeding. In our own observations during the years 1954-61 we have identified 215 species; of these, 161 have nested and five others probably do so. DESCRIPTION OF THE TERRAIN The area covered by our investigations consists mainly of ponds, woods and meadows in the district of Milicz, situated in a region which was formerly inundated and traversed by numerous arms of the river. The present woods are remnants of a vast swampy forest which surrounded the Barycz some centuries ago. Trie river now flows in a single bed; the former river arms and inundated land have in the course of centuries been transformed into the ponds where the Carp breed, and the swamp}' areas have been drained and turned to woods and meadows. The common feature of the three types of habitat is that they are interconnected by the former river beds. Most of these are now dry, but they are still quite conspicuous. The area covered by our study is a strip of land varying in width from about six to sixteen miles (10-25 km.) situated on both sides of the Barycz between two towns, Zmigrod in the west and Bartniki in the east (Fig. 1). The reserve occupies 60% of the strip. This tract of land, however transformed by man, has always been a favourite nesting haunt of many birds, especially aquatic species, and during migration periods it serves as an inland oasis for migrants which can rest and feed there. In this section of the Barycz valley there are two smaller valleys where large groups of ponds are concentrated—the valley of Milicz, approximately 330-360 feet above sea level, in the east, and the valley of Zmigrod in the west. In the vicinity of SUIQW these two valleys are separated by a ridge 426 feet (130 m.) above sea level, the main valley narrowing here to a mile (about 1.6 km.). The largest group of ponds is found in the Milicz valley. The environments are of two kinds. In the Zmigrod valley, and also in the southern part of the Milicz valley, the ponds are enclosed by extensive swampy meadows and deciduous woods, while in the remaining part of the Milicz valley they are surrounded by dry meadows and fields. Accordingly, there are certain differences in the bird popu- 248 ORNITHOLOGY OF THE BARYCZ VALLEY lation, the most outstanding being that on the ponds situated within woods. These have fewer geese and grebes, but some Passerines and bird of prey occur in large numbers. Moreover, a more marked species differentiation of the bird population can be seen there. Ponds The ponds are concentrated in four big groups which correspond to the administrative divisions of the fishing farms: (a) Radziadz in the west and south-west of the Milicz district; (b) Ruda Sulowska in the central part; (c) Milicz and Potasznia in the north-east; and (d) Kros- nice in the south-east (Fig. i). Most of them are drained each autumn so that the Carp may be caught and they are filled again between February and April. In each of the four groups, however, there are some ponds stocked with fry; these are filled with water all the year round. The sizes of the ponds vary greatly from no more than a dozen acres to several hundred acres or even larger. The largest pond in the Radziadz group, "Stary" ("The Old One"), has an area of about 1,040 acres (420 hectares). However, they are not deep. The most shallow, those in which fry are kept, are only twenty inches (some 50 cm.); and, though parts of the so-called "productive" ponds may be as much as seventy inches (about 180 cm.), they also have many shallow places where the water is barely more than 15 inches (about 40 cm.). In such places there is luxuriant water vegetation. AH ponds have a net of bed ditches as well as fisheries, i.e. places where fish resort when the ponds are being drained; the fisheries reach a depth of 10-13 feet (about 3-4 m.). The ponds may be divided into two distinct categories. In the first - (Fig. 2a), the emergent hydrophytes are markedly differentiated. The section adjoining the water's edge consists of woods, deciduous or mixed; these pass into thickets of alder [Alnus) and osier (Salix), and then, as the water becomes deeper, there are sedges (Carex) and reeds (Phragmites communis). In addition, there are islets of reed scattered all over the water surface and along the bed trenches. In the second category (Fig. 2b) the emergent hydrophytes, chiefly reeds, make up about 50% of the whole area. These form an edge zone, which is mainly narrow though its tongues may reach far into the pond, and there are also reed islets of varying size. On some ponds of this type are found marshy meadows which extend from the banks into the water, gradually passing into sedges growing in tufts and then into the zone of reeds. Ponds of this kind make up two-thirds of the Milicz water area. Apart from these two types, one can distinguish sections of ponds which owe their origin to the building up of new, higher dykes and 249 BRITISH BIRDS FIG. 2. Diagrammatic sketches of the two main types of ponds in the Barycz valley, Poland. In the first (a), there are deciduous and mixed woods adjoining the water's edge; these pass into thickets of alder and osier and thence into sedges and reeds. In the second (b), the water plants make up half the whole area, with tongues reaching into the pond and reed islets of varying size; there are often also marshy meadows extending from the banks into the water, gradually passing into sedges and then the edge zone of reeds. For a fuller explanation see page 249 250 ORNITHOLOGY OF THE BARYCZ VALLEY the consequent rise in the water level.

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