Nesting birds. Regularly occurring in the Lake Ladoga area
today are 256 bird species belonging to 17 orders (see Table 3.12). Twenty-two more species have recently
gone extinct or are accidental visitors. This comprises 89% of the total number
of bird species in the Leningrad region (Kondratjev et al., in press) and more than
the total number in Karelia (Zimin et al.,
1993). Lake Ladoga area is a most valuable area for the conservation of rare and endangered bird species. The bird fauna of the region numbers 103 "Red Data Book" species, 72 of which nest or are presumed to do so in the area.
High diversity of the bird fauna in the Lake Ladoga area is due to the diversity of environments satisfying the ecological requirements of highly varied bird groups.
To mention a few regionally rare species, black-throated diver, and (in northern Lake Ladoga area) red-throated diver and smew regularly occur on inland lakes. Mires in the east and south of the Lake Ladoga area are nesting grounds for golden plover, Eurasian curlew, whimbrel, Jack snipe, black-tailed godwit, common redshank, osprey.
Another important reason for the high bird abundance is the
geographic position of the region (south-western periphery of the taiga zone,
borderline between Fennoscandia and the Russian plain) resulting in the
interpenetration of heterogeneous faunistic elements. The "mixing" of the
faunas was intensified even more by human-induced changes in the native
vegetation of the region, which made the bird fauna shift towards a more
southern type, this process still continuing. According to V.B. Zimin (1988) in Karelia in general, 42% of all bird species live in the northern margins of their ranges, whereas for some species the area is the eastern, western or southern limit of their permanent nesting range.
The Lake Ladoga as a habitat for birds
The Ladoga itself - is an attractive aquatory for numerous waterfowl and shorebirds.
The northern part of the lake is characterized by the unique complex of shorebirds, typical of marine islands and coasts, but almost never for inland freshwater body. This part of Ladoga is biotopically similar to the neighbour areas in the Gulf of Finland and the White Sea.
The southern part of Lake Ladoga is favourable for grebes, Ciconiiformes, rails, ducks, waders, gulls, terns, as well as birds of prey such as osprey, white-tailed sea eagle and marsh harrier. The southern part of the lake is much shallower and highly productive, while the shore is comprised of vast sandy beaches alternated by thick reed stands, wet meadows, mud flats and fens. The abundance of nesting shorebirds is particularly high near the estuaries of large rivers - Svir, Volkhov and Syass.
The continental part of the Lake Ladoga area is rich in wetlands, rivers, and streams, that provide for the high population density and rich species composition of hydrophilous birds. Another complex of dendrophilous species typical for the Russian Northwest is also well represented in this area covered in forests, chiefly represented by coniferous and mixed coniferous - secondary deciduous stands with some scattered nemoral elements. Intensive forestry caused the growth in the abundance of forest edge and shrub birds, as well as species typical for open areas
Migrating birds. Ladoga is an essential link in the European largest White Sea-Baltic Flyway, through which millions of birds from the Russian North migrate to their winter grounds in Western Europe and Africa. Lake Ladoga is an important factor influencing the distribution of migration routes and mass stopping places of migrating birds. In the spring most species migrate in the north-eastern direction. The summer-autumn migrations of shorebirds across Ladoga proceed chiefly in the south-western direction.
Over 50 species of birds of passage were noted in the Lake Ladoga
area in spring and autumn. The Ladoga region migration links cover an area from
Iceland to India, and from south Africa to Novaya Zemlya (Rezviy et al., 1995).
Lake Ladoga as a "crossroad" of migration routs
Rout No. 1 (spring migration). In the first half of spring swans and ducks (mallard, northern pintail, Eurasian wigeon, teals, mergansers, tufted duck, etc.) head to the Petrokrepost, Volkhov and Svir bays through the Neva bay of the Gulf of Finland and the southern part of the Karelian isthmus.
Rout No. 2 (spring migration). In the second half of May sea ducks (greater scaup, long-tailed duck, common and velvet scoters) and most brent and barnacle geese pass the area through the Gulf of Vyborg and north of the Karelian isthmus, coming to the Ladoga shore in the vicinity of Priozersk and forming aggregations around Valaam and in north-western Ladoga.
Rout No. 3 (spring migration). Tens of thousands of land birds approaching the lake from the south-west often refuse to take the risk of crossing a large body of water, and turn along the shore to the north or east forming narrow migration streams.
Rout No. 4 (autumn migration). During the end of summer and in autumn shorebirds migrate in the south-western direction without forming large-scale aggregations in the stopping places. The majority of birds moves along the northern and western coasts of the Lake.
Rout No. 5 (autumn migration). In the autumn land birds form a powerful stream of migrants along the Ladoga eastern shore.
The total number of migrating birds exceeds several millions both in spring and in autumn. From 1 to 3 million individuals of arctic ducks pass through the northern Ladoga, about 1.5 million of geese, over 400,000 of other waterfowl, as well as tens of thousands of passerines, pigeons, birds of prey and other land birds are passing through the southern Ladoga region in spring. In time of autumn migrations in some years over 3 million birds, chiefly passerines, pass along the Svir bay shore in the daytime, while total flow of diurnal migrants through Valaam in the autumn is about 400,000 individuals.
Most important for the spring migration of geese (bean,
white-fronted, graylag, lesser white-fronted) are stopping places where the
birds stay for 1-2 weeks to feed and regain energy. Feeding grounds are
confined to fields and meadows, which are limited in number in the region.
Hence, huge numbers of geese concentrate in the few suitable areas which are
traditionally held to for decades. Favourable conditions in the stopping places
are essential not only for the successful completion of the spring migration,
but also for the success of breeding in Arctic tundras. The largest goose
stopping places are found in the Svir lower reaches (up to 150,000-200,000 ind.
through spring) and in southern Karelia (up to 1 million ind. through spring;
Rezvy, 1997; Zimin et al., 1997). Smaller stopping places
of geese were recorded also near Sortavala and Pitkaranta (Zimin, 1999).
Thus, in the Lake Ladoga region, in general interesting area in
ornithological respect, a certain number of the most valuable territories for
bird fauna can now be identified (Fig.
3.3.2.2). Some of them were granted the national protection status
(zapovedniks, zakazniks, reservs, etc.). One area (Svirskaya bay) has been
proposed as a Ramsar site and thus has an international status. Several
territories have been already named or are under consideration as "Important
Bird Areas (IBA)" by the international non-governmental organization
BirdLife International.
