added a research item
Project
Long term study of the population of Whooper Swan Cygnus cygnus in south Poland [Długoterminowe badania populacji łabędzia krzykliwego w południowej Polsce]
Updates
0 new
0
Recommendations
0 new
0
Followers
0 new
8
Reads
1 new
304
Project log
![[object Object]](https://c5.rgstatic.net/m/435982309481010/images/template/default/author/author_default_m.jpg)
The Whooper Swan Cygnus cygnus (Linnaeus, 1758), along with the Mute Swan
and Trumpeter Swan, is the largest representative of the Anseriformes (Table 1). It is
a monotypic species, one of the six presently existing taxa of the genus. Throughout
its range the most distinctive, varying feature is the changeable bill pattern (Fig. 1).
There is no clear sexual dimorphism; however, males are slightly larger and heavier
than females. The average weight of an adult male during winter is 10.2 kg (7.2-13.5
kg), while that of a female – 9.2 kg (5.6-13.1 kg; Table 2). Of all swans, the Whooper
Swan has the broadest range. It inhabits Iceland, Scandinavia and a wide area in Asia,
up to the Pacific Ocean in the east (Fig. 2). The species breeds between 45°N and
70°N, mainly in the taiga. To the north of the continent, the natural range is limited
by the short period of summer, free of ice, and the length of the breeding cycle, associated
with the species’ substantial size. In Europe whooper swans are most numerous
in the north, with the largest populations in Finland (5,000-7,000 pairs), Sweden
(5,400 pairs), European part of Russia (at least 3,000-3,700 pairs) and Iceland (1,500-
2,500 pairs); moreover, 350-600 pairs breed in Norway (Table 3). Increasing populations
are present in the countries on the eastern coast of the Baltic Sea (Lithuania,
Latvia and Estonia) – 600-670 pairs (Table 4), as well as in Poland (131 pairs) and in
Germany (30-40 pairs)...
Waterfowl (Anatidae) are a group of birds in which parental care is performed by both parents (a pair) or, less often, by females only. Alternative social systems in this group have been recorded only occasionally. This paper describes three unusual cases of prolonged association between a pair and an additional male (the offspring or sibling of the primary pair) in breeding Whooper Swans (Cygnus cygnus). In all instances the three birds displayed no antagonistic behaviour towards family members, participated in territorial defence, and bred successfully. These cases are unusual in light of what is currently known about the social system of the
highly territorial Whooper Swan in particular and of Anatidae in general, and are typical of cooperative breeding. This shows that swans may occasionally form an alternative social system.
