From Latvia in the north-east to the Polish border in the far south, the eastern half of Lithuania is a broad swath of extensive forests and lakes. Yet, despite this abundance of water, there exists a paradox in that there is relatively little natural aquatic habitat of any great value to significant numbers of birds - most of the lakes are steep-banked, deep and provide little in the way of opportunities to either feed or breed.

The notable exceptions to this, including the internationally-important Nemunas Delta and the lakes of Zuvintas, Dusia and Metelys, are mostly in the south of the country or near the Baltic Sea. At these, the bird fauna is diverse and numerous, with both large numbers of breeding species and even greater numbers of migratory wildfowl. However, even though these sites are of extreme importance, they are also quite few in number, limited in geographical spread and, furthermore, of little use to the numerous waders that migrate across Lithuania, birds which require shallow water and exposed mud.

Fortunately, for all these birds, including the waders, there is an additional set of wetlands that have been created across the country, providing a range of habitats almost designer-labelled for birds. Of national importance in terms of biodiversity, these wetlands are the fish pools, a set of complex systems that are still run on a commercial basis. Their great attraction lies not only in the multitude of habitats available, including everything from open water to choked vegetation and reedbed, but also in the annual autumn practice of draining the pools in order to harvest the fish, thereby incidentally providing the habitat exceptionally rare in the Baltic area, that of exposed mud.

While the fish pools, which are dotted across most of Lithuania, vary considerably from one site to another in relation to their size and ornithological appeal, their overall importance cannot be understated. In the breeding season, many scarce species maintain strongholds on the pools, including Bitterns, grebes, and raptors, while come the passage periods the sites often literally throng with waterbirds of all descriptions, including the waders that are starved of feeding grounds elsewhere.

Of the numerous fish pools in Lithuania, there are very few that can match the excellent ornithological fauna to be found on the pools at Baltoji Vokė. The richness of these pools, along with the neighbouring Lake Papis, also excellent for birds, makes the area one of the most valuable wildlife sites in eastern Lithuania. Together, the lake, fish pools and adjacent peatlands support both an impressive selection of breeding species, many of which are listed in the country’s Red Data Book, and a concentration of migratory birds not found elsewhere in this part of the country.

Site Description

Baltoji Vokė lies in the Šalčininkai region of south-east Lithuania and is located between the Rivers Neris and Merkys, about 28 km south of the capital and only a little more from the Belorussian border. On almost all sides, the site is surrounded by extensive pine forests, namely Rūdninkų Giria to the south and east and Ropėjos Miškas to the north, while through the centre of the area flows the River Vokė, a tributary of the Neris. This river feeds both Lake Papis and the fish pools. Baltoji Vokė itself is characterised by a wealth of different habitats. Sitting almost as a centrepiece is the large shallow Lake Papis, with its wide fringe of reedbeds, peaty shallows and marshy islands. The lake hosts many different species, but amongst the most important are the breeding Bitterns and terns and large numbers of migratory wildfowl.

Surrounding the lake is a belt of damp alder woodland, as well as a system of collective gardens near the village of Mikašiunai and traditionally farmed fields and natural meadows to the south. To the immediate north of the lake are the peatlands, an expanse of reed and marsh broadly flanking the River Vokė. Through successive generations of peat extraction, now largely ceased, the area is characterised by a wide variety of habitats, ranging from regenerating scrub through to extensive reedbeds and shallow peaty pools. The peatlands are of key importance in that they provide breeding habitat for many wetland species, including wildfowl, waders, crakes and numerous passerines.

 Adjacent to these areas, and separated by shrubs and overgrown pools, are the fish pools. These are notable for their very high habitat diversity and thus appeal to birds. Some pools are dry, containing a mix of grass, shrub growth and damp sedge, while the rest are commercially farmed, though still biologically extremely varied with areas of open water, reedbeds, birch thickets, swampy margins and wet grassland. The more open pools are especially favoured by diving ducks, grebes and other wildfowl, whilst the shallower are characterised by grassy margins and islands, thereby attracting the greatest volume of herons, storks, dabbling ducks and waders, as well as breeding species such as Citrine Wagtail.In the autumn, usually from mid-August, the pools are drained one by one, creating excellent conditions for migrating birds, especially waders. A final link in the rich chain of biodiversity that exists at Baltoji Vokė are the dry land habitats, which include extensive pine forests, sandy dykes between pools, meadows both east and west of the pools, plus numerous patches of scrubland and regenerating growth. The forests support various raptors and owls, Hazel Grouse and Golden Orioles, whilst the meadowland holds Corncrakes and Quails, with Hoopoes, Red-backed Shrikes and occasional Blyth’s Reed Warblers scattered elsewhere.

Ornithological Outline.

Divers, Grebes, Cormorants and 'Long-legs'

In this broad grouping of birds, Baltoji Vokė is well represented. Not only do both Red-throated and Black-throated Divers occur as occasional migrants, but so too are all of Europe's regular grebes frequent, along with very good numbers of herons and storks. Of the grebes, the most abundant is Great Crested Grebe, with a breeding population of up to 25 pairs and a summer concentration of up to 150 birds. Two of its smaller relatives, namely Little and Black-necked Grebes, are also fairly common, with the former breeding in small numbers and the latter, although as yet not nesting, sometimes present throughout the spring and summer and surely a potential candidate for future breeding. Red-necked Grebe is another possible breeder, although is at present a fairly scarce annual migrant, as is usually the case with Slavonian Grebe. Slavonian Grebes, however, confounded all expectations in 1999 with a single pair breeding, only the second such case in Lithuania.

Cormorants, as in much of Lithuania, are growing in abundance at Baltoji Vokė. Their current status is that of a common migrant, occurring in particularly large flocks in the latter autumns of the period. To date, summer numbers remain comparatively low, although it would be reasonable to expect this to change in the future, with breeding always a possibility.

The shallow fish pools, especially those semi-dry or the process of being drained, are of great importance to Grey Herons, as well as Black Storks and occasionally Cranes, providing for each a vital feeding habitat. Whilst all these birds breed in the area (Grey Herons in Ropėjos Miškas and Black Storks and Cranes in Rūdninkų Giria), even greater numbers occur on passage. Creating a most impressive sight, Grey Herons and Black Storks are often present in very large flocks in the migration periods, with the counts sometimes peaking at over 350 and 30 respectively in August to September. This concentration of Black Storks, amongst the largest recorded in Lithuania, points to the importance of the fish pools as a feeding site for these birds.

Two further species worthy of mention are Bittern and Little Bittern – the first of these breeds in good numbers each year, while the latter occasionally occurs and probably breeds from time to time. Finally, the rich habitat at Baltoji Vokė is also of appeal to vagrants, including Lithuania's second and third Purple Herons, Lithuania’s fourth Night Herons, as well as a Little and large influxes of Great White Egrets each year.

Wildfowl

All three of Europe's swans, seven of its geese and over twenty species of duck have been recorded at Baltoji Vokė since 1997, as well as Coot, Moorhen and various rallids. Breeding species include Mute Swan, Whooper Swan, Mallard, Garganey, Pochard, Tufted Duck, Goldeneye, Goosander, Coot and sometimes Shoveler and Gadwall. Of these, the most abundant are Mute Swan, Tufted Duck, Goldeneye and Coot, though the most significant are the Whooper Swans (seven to eight pairs currently), a species not very abundant as a breeder in Lithuania. Whilst good numbers of these birds breed, Baltoji Vokė is moreover an excellent migration site. Both the lake and fish pools hold very important staging populations in spring and autumn, with the months of April and August to October being particularly good. In terms of volume, wildfowl occur in the greatest number in late September and early October, when totals can peak up towards 10,000.These are also the periods when rarities are most likely, the most noteworthy of which have been a group of four Pink-footed Geese (the first for Lithuania), a Red-breasted Goose, Ferruginous Ducks on two occasions, as well as occasional Barnacle Geese, both Velvet and Common Scoters and several Red-crested Pochard. Smew, Scaup and Long-tailed Ducks are all rather more common, the former occasionally occurring in number over 100.

Raptors

A rich variety of raptors, from White-tailed Eagle to Merlin, occur with  regularity at Baltoji Vokė. Indeed, over twenty species have been recorded, with almost half of them either breeding or doing so in the area and using the site for hunting.  Of the breeders, the impressive White-tailed Eagle is the most notable. Daily visitors from the earliest rays of spring through to late autumn, the population of Papis and the fish pools includes not only a breeding pair, in recent years a second pair, but also a number of immatures and sub-adults and, at certain times of the year, up to nine or ten birds can be seen.

Also regular is Lesser Spotted Eagle, both as a breeder and as a passage migrant. Its larger cousin, however, Spotted Eagle, is very rare and has only occurred as an accidental vagrant. Other eagles that occasionally occur include both Golden Eagles and Short-toed Eagle and, on one occasion, a Booted Eagle. Other species that have bred include Merlin (extremely rare), Montagu's Harrier, Black Kite and Honey Buzzard, whilst Osprey is frequent on passage and probably breeds nearby in some years. Of the other commoner breeding raptors, Marsh Harriers are the most abundant (with about five pairs) and Hobby, Sparrowhawk, Goshawk and Common Buzzard all breed in surrounding forest. Baltoji Vokė also attracts a number of migrant and winter raptors, including regular movements of Sparrowhawks and Goshawks and, more unusual, annual spring and autumn Peregrine Falcons, Merlins and Hen Harriers. On the Vokė and Lukna meadows in particular, good numbers of both Common and Rough-legged Buzzards are also recorded in the autumn, with smaller numbers usually staying on to spend the winter. Rarer still, an immature Gyr Falcon, a vagrant to Lithuania, has been found on the Lukna meadows on one occasion, whilst Red-footed Falcons, another vagrant species, have been seen several times, spring and autumn.

Gamebirds and Rallids

In this grouping, several species are represented. Both Spotted and Little Crake breed, particularly in the peatlands, as do Water Rails at Papis and presumably elsewhere. Grey Partridge can be encountered in meadows across the area and, in summer months, both Corncrakes and Quail occur, breeding in small numbers. Adjacent forests have Hazel Grouse and Black Grouse, the latter also occasionally occurring at the fish pools and peatlands. Finally, a Capercaillie has also been recorded on a single occasion, a female on a track between the fish pools in autumn.

Waders

In addition to Lapwings and Common Snipe, the rich habitats of the peatlands attract breeding Redshanks (two pairs) and both Wood and Green Sandpipers (at least three pairs and four pairs of each). As such, it is clear that the peatlands are of regional importance to these birds, especially given that two of the species are listed in the Red Data Book of Lithuania.  At the neighbouring fish pools, fewer species of waders actually breed and those that do - including Lapwing, Black-tailed Godwit, Common Redshank and Little Ringed Plover - usually suffer a rather limited success (due to fluctuating water levels that flood out their nests). This said, the value of the Baltoji Vokė fish pools to this group of birds is, nonetheless, immense and cannot be understated. Huge numbers of migrating waders descend upon the pools in both spring and autumn, annually approaching peaks of 1000 and sometimes totalling more than 3000. Almost 30 species are recorded annually, with the most abundant being Lapwing, Ruff, Wood Sandpiper, Dunlin and, depending on the year, Little Stint.

In addition, many species are recorded that are either scarce in Lithuania or at inland sites. These included annual Broad-billed Sandpipers and Red-necked Phalaropes, impressive numbers of Temminck's Stints, plus Whimbrels, Turnstones, Knots, Bar-tailed Godwits and, rare inland, Avocet. A number of extreme rarities have also occurred, including an American Golden Plover (first record for Lithuania), two Black-winged Pratincoles (first and second records), two Pectoral Sandpipers (second and third records), Terek Sandpipers and a Dotteral. One further species deserving special mention in this section is Marsh Sandpiper - this species is rare in Lithuania and prior to 1997 had not been recorded breeding. At Baltoji Vokė, however, Marsh Sandpipers are fairly regular, appearing every spring and indeed probably bred at the fish pools in 1997, probably did so in 1998 and again possibly in 2000.

Gulls and Terns

Gulls and terns are frequent. Over fifteen species have been recorded at Baltoji Vokė, of which six bred, four can be considered common visitors, four scarce migrants and one a new species for Lithuania. The most abundant species is Black-headed Gull, with a large colony of up to 350 pairs on Lake Papis and many more occurring as migrants. In addition, the colony also supports a few Common Gulls and sometimes Black Terns. Up to 40 pairs of Black Terns also breed in the peatlands, along with occasional pairs of White-winged Black Terns. Both these marsh terns are also common migrants, sometimes occurring in very large numbers, eg. an influx of 1140 White-winged Black Terns in May 1998. As well as these, numerous pairs of Common Terns breed and Little Terns sometimes attempt to do so at the fish pools (though are hindered by fluctuating water levels). The Common Tern population was enhanced in 2001 with the provision of artificial nesting rafts at the fish pools - an immediate hit, almost 70 pairs had colonised the two rafts by 2002. Of the less common migrants, there were three species of particular interest in the period. Most noteworthy, the first for Lithuania, an adult Mediterranean Gull appeared on the fish pools in May to June 1998, with remarkably a pair also found on Lake Papis in 2001. This species has since been recorded a number of times in Lithuania, including a single breeding record. Also not common in eastern Lithuania, there have been several records of Whiskered Terns. Not quite so rare, but still scarce, especially inland, are Caspian Terns. However, at Baltoji Vokė they appear fairly regular, with several per year, most of which in the autumn. Arctic Terns have also occurred.

Owls

The most widespread of the breeding owls is Long-eared Owls, breeding in both the extensive pine forests and within Baltoji Voke vilage itself. Rarer, but still widespread, Tengmalm’s Owl also occurs throughout the area, though is rarely seen by chance and is best found by voice in the early spring.  Discovered in 2002, there is also a pair of Eagle Owls breeding, though again are very difficult to locate. Tawny Owls has also been recorded, though appears to be scarce. it is likely that other species, such as Pygmy Owl, are also present.

Near Passerines

Although Baltoji Vokė is primarily noted for its waterbirds,  there are also several other special birds worthy of mention. In the late 1990s, Rollers and Hoopoes, both listed in the Red Data Book, maintained populations in the dry habitats around the fish pools. During the period, however, while Hoopoes continued to flourish, with as many as five pairs breeding annually, Rollers declined steadily and, by 2002, appeared to have become locally extinct. Also in the Red Data Book, a couple of pairs of Stock Doves breed, Turtle Doves most years and Kingfishers on occasion.  Of the more common birds in this category, Swifts and Cuckoos are abundant, whilst members of the woodpecker family include breeding Wrynecks and Lesser Spotted Woodpecker, plus Black Woodpecker in neighbouring forests and Middle Spotted Woodpecker as an accidental visitor.

Passerines

Over a hundred species of passerines have been recorded in the area around Baltoji Vokė, with about 80 of these breeding. The majority of the breeders are those which either favour reedbeds, such as the large numbers of Great Reed Warblers, Sedge Warblers and Reed Buntings, or associated damp areas and bushland, including such birds as Yellow Wagtails, Thrush Nightingales, River Warblers, Barred Warblers, Penduline Tits and Rosefinches. Neighbouring forests support all the typical species one might expect, along with Golden Orioles, Nutcrackers and a small number of Red-breasted Flycatchers A number of very scarce passerines also breed at Baltoji Vokė and include several listed in the Red Data Book. The most noteworthy of these are the five pairs of Citrine Wagtails, a species with a very limited range in Lithuania, Tawny Pipit, a minimum of three pairs of Blyth's Reed Warblers, up to six pairs of Great Grey Shrikes and good numbers of Red-backed Shrikes.

In addition, Bluethroats breed in the peatlands and are occasionally recorded at the fish pools and Bearded Tits occur annually, breeding most years. Many migrants also use the area during the spring and autumn passage periods, though a ringing programme needs to be established to quantify the importance of Baltoji Vokė for these birds. There have been two records of birds new to Lithuania: a Short-toed Lark (a new species) and a Yellow Wagtail of the race 'feldegg'  (a new sub-species). Also noteworthy, Rose-coloured Starling have occurred on a couple of occasions, Twite a few times and flocks of Shore Lark on a couple of occasions. Other interesting passerines recorded during the period included Snow Buntings and both Arctic and Lesser Redpolls (mixed with Mealy Redpolls).