Ladoga Research Papers - Academia.edu (original) (raw)

The Ladoga Ornithological Station (LOS) of the Biological Research Institute of Saint-Petersburg
University for 37 years serves as a research observatory for regular visual observation of bird
migration, as well as a place for capturing, ringing and recording the parameters of living birds. The
results of the studies as well as characteristics of environmental conditions of the place were
published earlier (Noskov, Zimin, Rezvy, 1975; Noskov et al, 1981; Noskov, Smirnov, 1998; Rezvy,
Noskov, Gaginskaya et al, 1995; Rezvy, 1997; Gaginskaya et al, 2001, Noskov, Smirnov, Rymkevich,
2001; Noskov, Rymkevich, Smirnov, 2002).
The observations were carried out according to E. V. Kumari’s method (1955, 1979). The method
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was partially modified: the evening route was replaced by a bird recording made from the tower
located on the coast of Lake Ladoga on the territory of the LOS.
To evaluate the number of individuals and dates of migrations of some species, the results
of visual bird counts were used along with the data on birds trapped by big stationary traps
functioning since the beginning of the study. The «method of decoy birds» was used to record rare
and sparse species.
The four years presented in this study were notably different in weather conditions. The earliest
spring warming was detected in 2002. It started in the third ten-days period of March, however, the
first ten-days period of April happened to be cold (the average temperature for the period was
negative). The long-term frosty weather did not return anymore that year.
Substantial returns of cold weather were recorded in the spring of 2001 (between 11 and 17 April
and between 22 and 26 May) and 2003 (between 24 and 28 April). The most stable warm weather
without cold spells stayed throughout the spring of 2004.
In 2002, large flats and beaches were formed as a result of the lowest for the last 50 years water
level of Lake Ladoga. Migrating geese, waders, gulls were attracted by these circumstances that
explains the maximal numbers of these birds recorded for this year. The year 2004 was characterized
by the highest water level; all the beaches were flooded.
The costal zone of the Svir Bay of Lake Ladoga was cleared from the ice, forming conditions for
stopovers of waterfowl in 2001 – on 14 April; in 2002 – on 27 April; in 2004 – on 4 May (but
a narrow lane of open water appeared on 22 April, 2003). Spaces of open water were recorded in
river mouths on 18 April, 2004; the ice was flown away by the eastern wind.
An analysis of the observation results allows us to make the following conclusions:
The early onset of warm weather in spring of 2002 affected the dates of migration of the birds
of many species arriving in the early period of spring migration. Most of the species arrived 8-16 days
earlier than long-term average. At the same time, the May chill weather, that came 9–12 May and 17–25
May, shifted the arrival dates of the migrants arriving in mid-May closer to the long-term average, and
resulted in slight retardation of birds appearing at the observation point in the third decade of the month.
The southwestern direction along the coastal line prevailed in most land migrants during all four
studied seasons, as well as in other years. The opposite, northwestern, direction was kept by
Crossbills, Redpolls and some of the Hooded Crows. Most waterfowl (geese, swans, dabbling and
diving ducks, Common, Black-headed, and Little Gulls), as well as Snow Buntings, Skylarks and
Woodlarks moved north-north-eastwards. They approached from the water of the Bay and crossed
the shoreline close to the observation point. A part of flocks of dabbling ducks, Scaups, Common and
Velvet Scoters flew from the open water area of the Svir Bay north-north-westwards along the
shoreline within 3 to 8 km from the coast.
The greatest fluctuations in the bird numbers during these four seasons were found for thrushes,
the Chaffinch, Siskin and Redpoll. The data on records of rare species for this area, such as the
Garganey, Pochard, Smew, Booted Warbler, Wood Lark, Black Redstart, and Hawfinch are presented.