Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Cygnus
Synonyms: Anas olor Gmelin
Common names: Russian: Lebed-shipun; Azerbaijani: Fysyldayan gu gushu; English: Mute swan
Adult individuals are pure white. At maxilla basis there is a big black outgrowtgh, less pronounced in females. The major part of beak from the end is red, only the nail, maxilla borders, nostril area and bare space between beak and eye are black, i.e. the beak basis (excluding nail) has black color. Legs are black. Eyes are dark-brown. Unlike adults young specimens are dark gray with gray-brown beak and red legs. By autumn of the second year of life they attain coloration typical of adults.
Total length is 1,520 mm, wing – 570-620 mm, shank - 100-128 mm, beak (from mouth corner) – 98-108 mm. Weight is 8-13 kg, sometimes up to 16 and even 22.5 kg (Ivanov et al., 1951; Dementiev et al., 1951; Tuaev, 1977). When at water, the neck of the bird is bent and resembles question mark. The voice is hissing.
Intraspecific forms. None
Related forms. In the Caspian region there are 2 more swan species of : whooper swan
(Cygnus cygnus) and Bewick's swan (Cygnus columbianus bewickii or Cygnus
bewickii). Their beaks are not red-black but black-yellow. Black color is at
the end of beak unlike that of mute swan. Whooper swan is similar to mute swan in size (weight up to 11 kg), Bewick’s swan is twice smaller (up to 6.5 kg) and differs from whooper swan by the bigger space of black color on the beak (the border between black and yellow is almost in the center of the beak, closer to eyes).
In Azerbaijan the species can be found during wintering and in little quantities - at nestling (Shirvanskii nature reserve) along the coast and in the inland lakes. Along the Caspian coast it is concentrated at traditional wintering places in bays, between islands of Apsheron and Baku archipelagos as well as in coastal lagoons from Agzybir lake (Divichnskiy firth) to Kyzylagach reserve including Gushgel lake (Chala, Shorgel) in Shirvanskii reserve. In summer one can frequently find birds who neither left for the north nor nested. In the opinion of a number of Azerbaijani authors mute swan’s wintering occurs only in Kyzylagach reserve and adjacent areas (Vereschagin, 1950), however records of 1990-s showed that this species could be found wintering at farther north areas (along Apsheron coast, Shirvanskii reserve, etc.), though whooper swan prevailed in these areas.
Status as per International Red Data Book: N/A
Status as per National Red Data Books: rare species
Ecologo-taxonomic group. Waterfowl.
Origin. European.
World distribution. The species is distributed from Europe (except south-west) to Kazakhstan, southern Siberia and the northern China, in the mountainous areas of China and in the Central Asia, it is not found in tundra and northern part of taiga. Wintering takes place, mainly, in subtropical and tropical zones to the south from nesting places (eastern Mediterranean, the Black and Caspian Seas, Persian Gulf area, Middle (Central) Asia, Yellow Sea area).
Habitat. Water bodies with reed, bushes and other vegetation.
Migrations. The birds arrive to Azerbaijan in December (in warm winters – in mid-January) for wintering, leaves in late February-March. In cold severe winters the birds sag because of the lack of food and therefore leave in late March (Karabanova, 1991).
Relation to temperature. Mute swan can easily resist low temperatures but cannot live if the water body is frozen. High temperatures ( above
30-35oC), apparently, hamper the reproduction due to intensive development of ectoparasites and cause discomfort because of well-developed fuzz under contour feathers.
Vertical distribution. Mute swan prefers waters with depth of not more than 1-5 m, as it feeds on underwater plants and invertebrates at the bottom or in the water column, submerging into water at full length of the neck.
Relation to fluctuations of the sea level. The rise of the Caspian Sea level leads to increase of shallow areas and, consequently, swan habitat areas.
Feeding type. Mixed (feeds on aquatic plants and invertebrates).
Feeding behavior. Takes food from the bottom of water bodies, in the water column or from the surface. Swan does not dive but can plunge into water at the full length of the neck (up to shoulders) instead
Food spectrum. Aquatic plants and invertebrates
Food supply. Reeds of underwater plants, benthos.
Quantitative characteristics of feeding. Food consumption composes about 20-25% of body weight per day.
Reproduction type. Sexual. Swans create couples once in a lifetime, partner can be substituted only in case of its death.
Terms of reproduction. Egg laying starts in late April-early May.
Fecundity. 7-9 olive-green eggs in a clutch.
Limiting factors. Accessibility of places for nesting and night rest to terrestrial predators and man.
In the south of the habitat area - high temperatures and excessive development of ectoparasites, in the north – competition with relative species.
Life-history stages. The nest is constructed in thick growth of reed only by female . Incubation lasts for about 35 days. Nestling starts flying at the age of 4 months.
The basic stages of the year cycle: wintering, spring flight, reproduction, molting, autumn flight. Full molting with loss of flight ability occurs in July-August, partial change of contour rectrix – in September-December.
Relation to environmental factors. N/A.
Age of maturity. Mute swan matures at the age of 4 years old.
Thermal conditions of development. High temperature (above 30-350 C) hampers reproduction and normal growth of nestlings.
Quantitative characteristics of growth. N/A.
Sexual structure. Sexual ratio is close to 1:1.
Size-age structure. Mute swan live for 15-20 years and more. Not less than 50% of the
population are young birds (immature). The quantity of birds during spring migration comprises approximately 40% of birds during autumn migration.
Quantitative characteristics. IIn 1993, the mute swan number in the entire Caspian region was estimated as 200 thousand birds (Krivenko, 1993).
Total number of swans in Azerbaijan, counted through air survey in 1993, comprised 6560 specimens (the winter was rather severe). The abundance of mute swan at wintering sites (as well as that of the other swans of the Caspian) depends on winter temperature. It declines sharply during warm winters, that is why most places of traditional wintering here are not regular.
Biomass (supposing average weight is 10 kg) amounts to 197,000-205,000 kg for the Northern Caspian, 215,000-152,000 kg for the eastern coast of the Caspian, 19,000-13,000 kg for Dagestan, and 65,600 kg for Azerbaijan.
Population trends. Mute swan was listed in the USSR Red Book and Azerbaijan Red Book. In 1960-s – 1970-s this species was not abundant, starting with 1980-s itsabundance increased significantly throughout its area. The Caspian-Central-Asian population number increased approximately from 40-45 thousand birds in 1970-s to 250 thousand birds in 1990-s (Krivonosov et al., 1977; Krivonosov, 1991; Scott, Rose, 1996).
In the Caspian biocenosis mute swan is in the middle of the pyramid as it feeds on aquatic plants and invertebrates. However, because of big size it has no enemies among birds and aquatic predators and it is not a regular food for other animals.
Certain birds may suffer from the attacks of mammal predators at shallow waters. Mute swan is aggressive to other birds, especially during the period of reproduction. Excessive increase in abundance at certain places can lead to the decrease in abundance of game species, specifically, ducks.
Formerly mute swan was one of the most important commercial species for local population along the Caspian
coast. It has a great aesthetic value as one of the most beautiful birds of the Caspian fauna.
Human impact/Threats. In Caspian region men can be considered as the most important danger to mute swans. Even after the ban on hunting the cases of poaching are not uncommon, there are even cases of open selling the killed birds at the roads and markets.
Swans are very vulnerableto oil pollution. Birds swimming in water do not recognize an oil spot as danger and swim in it until their plumage sticks and they lose the ability to fly. As a result of dissolved feathers’ oiling due to hydrocarbon contamination, birds lose thermo insulation characteristics and freeze in water during winter period. Polluted birds lose weight and die from exhaustion. When trying to clean off oil from the plumage birds inevitably swallow it that leads to intoxication . In 1990, there was recorded a mass swans mortality from oil pollution at Tashagyl (Apsheron) lake where regular oil pollution took place, the lake became an oil trap for birds for many years (Sultanov, 1991). Occasional oil spills in the Caspian (Vereschagin, 1946; Sultanov et al. 1998; Sultanov, 1998) led to mass mortality of waterfowl not once (up to 35 thousand birds from one spill) and these present a potential threat for swans, especially for those spending winter along the sea coast, where oil spills could be disseminated from far distances (hundreds kilometers).
Conservation measures. The conservation of existing Caspian reserves and sanctuaries, which are important places of mute swan concentrations at wintering, nestling or flight.
Vereschagin N.K. 1950. Wintering and hunting of waterfowl in Azerbaijan. Proc. Zoological Institute, AN Azerbaijan SSR. Vol. 14. Baku (in Russian).
Dementiev G.P. 1951. Birds of the Soviet Union. Vol.2, Anseriformes, M.-L. (in Russian)
Karabanova N.I. 1991. Migrations of birds of north-east Azerbaijan. Abstract of Ph.D. thesis. Kishinev. 22 p (in Russian).
Krivonosov G.A., Vasiliev V.I., Rusanov G.M., Morozkin N.I., Pishvanov Yu.V. 1977. Waterfowl wintering at the Caspian in 1974-1975. In: “USSR waterfowl resources, their reproduction and use”. M., Nauka publishers.Pp. 55-56.
Sultanov E.G. 1991. Anthropogenic causes of birds mortality during their flight along the western shore of the Caspian sea. Abstr. 1st International Conference on the Caspian sea problems. Baku. Elm publishers. Pp. 75-76 (in Russian).
Sultanov E., S.Gumbatova, T.Kerimov, and N. Agaeva 1998. The case of mass mortality of birds from oil at the Gil islands in March 1998. In: “Regional studies and protection of environment in Azerbaijan. (Proc. Conference) Baku. Pp. 63-65 (in Russian).
Sultanov E., T.Kerimov, S.Aliev, S.Gumbatova, and N. Agaeva. Potential Ramsar territories (Wetlands of International importance) in Azerbaijan (ed. E.G.Sultanov). Baku. Wetlands International AEME, 152 pp. (in Russian and Azeri).
Sultanov E.G. and A.M. Musaev. 2000. Wildlife of Azerbaijan (Ed. M.A. Musaev). Vol.3. Vertebrates. Baku. Elm publishers. Pp. 290-301 (in Russian).
Sultanov E.G. and G.T. Mustafaev. 1994. Main results of winter air survey of birds in Azerbaijan. Proc. 1-st International Conference. “Birds of Caucasus”. Stavropol. Pp. 47-48 (in Russian).Tugaringov A.N., E.N. Kozlova 1951. Anseriformes. In: “Birds of USSR, M.-L., 1: 90-155 (in Russian)..
Krivenko V.G. 1991. The current status of waterfowl resources and their habitats in the Middle region of the former USSR. In: Moser M. and van Vessen J. (eds), Wetland and waterfowl conservation in South and West Asia. Proc. Int. Symp., Karachi. Pakistan. P.72077/IWB Special publication No.25; AWB Publication No. 85.
Krivonosov G.A. 1991 The status and distribution of the mute swan Cygnus olor in the USSR, A review with recent census. In: Sears J. (ed), Proc. 3rd International Swan Symposium, pp. 33-38, Wildfowl Supplement No. 1.
Derek A. Scott and Paul M.Rose. 1996. Atlas of Anatidae Populations in Africa and Western Eurasia. Wetlands International Publication. 41, 336 pp.
Elchin Sultanov. 1998. Mass mortality of birds from oil near the Caspian coast of Azerbaijan in March 1998. In: “Strategies for Conserving Migratory Waterbirds”. Proc. workshop 2, 2nd International Conference of Wetlands and Development, Dakar, Senegal. Wetlands International Publication.
E.G. Sultanov (Zoological Institute,Azerbaijanian Academy of Sciences, Baku, Azerbaijan)