Table 2 Diet composition (volume % of species in the fecal samples) of Mute Swan, Bewick’s swan and Whooper swan in spring

20 February – 20 March

Chlorophyta

60.63 (4.03)

-

55.25 (6.38)

 Chaetomorpha sp.

0.13 (0.13)

-

0 (0)

 Cladophora sp.

59.94 (4.09)

-

55.13 (6.43)

 Oedogonium sp.

0.19 (0.19)

-

0 (0)

 Rhizoclonium sp.

0.38 (0.26)

-

0.13 (0.13)

Phaeophyta

2.63 (0.98)

-

1.81 (0.74)

 Fucus sp. + Dictiota dichotoma

2.63 (0.98)

-

1.81 (0.74)

Bacillariophyta

0.69 (0.51)

-

0 (0)

 Tabellaria fenestrata

0.63 (0.51)

-

0 (0)

 Diatoma elongatum

0.06 (0.06)

-

0 (0)

Roots, rhizomes and tubers of vascular submerged and coastal plants

5.06 (1.62)

-

13.63 (5.33)

 Phragmites australis

3.75 (1.25)

-

11.25 (4.37)

 Bolboschoenus maritimus

1.31 (0.55)

-

0.81 (0.45)

 Schoenoplectus tabernaemontani

0 (0)

-

1.19 (0.79)

 Agrostis sp.

0 (0)

-

0.38 (0.26)

Vegetative parts of vascular submerged and coastal plants

9.88 (1.93)

-

5.56 (1.55)

 Stuckenia pectinata

8.69 (1.91)

-

4.06 (1.29)

 Potamogeton perfoliatus

1.19 (0.42)

-

1.5 (0.96)

Detritus

21.13 (4.4)

-

23.75 (6.51)

21 March – 28 April

Chlorophyta

47.33 (4.85)

47.80 (6.98)

14.33 (5.53)

 Chaetomorpha sp.

2.3 (0.58)

0.1 (0.07)

0.07 (0.07)

 Cladofora sp.

29 (5.54)

36.4 (5.83)

11.83 (4.86)

 Microspora amoena

0.23 (0.2)

0 (0)

0.03 (0.03)

 Mougeotia sp.

0.37 (0.19)

0.3 (0.19)

0.78 (0.36)

 Oedogonium sp.

1.57 (0.48)

0.1 (0.07)

0.07 (0.05)

 Rhizoclonium sp.

6.4 (3.49)

2.93 (1)

0.43 (0.24)

 Spirogyra sp.

0.1 (0.07)

1.27 (0.62)

0.92 (0.39)

 Stigeoclonium sp.

2.17 (0.76)

6.5 (3.83)

0.03 (0.03)

 Ulothrix zonata

0.17 (0.08)

0.03 (0.03)

0 (0)

 Ulva sp.

5.03 (1.88)

0.17 (0.17)

0.17 (0.17)

Phaeophyta

0 (0)

6.43 (2.42)

0.03 (0.03)

 Pylayella littoralis

0 (0)

6.43 (2.42)

0.03 (0.03)

Rhodophyta

4.3 (1.18)

0 (0)

0.07 (0.07)

 Ceramium tenuicorne

4.3 (1.18)

0 (0)

0.07 (0.07)

Xanthophyta

0.9 (0.44)

0 (0)

0 (0)

 Vaucheria sp.

0.9 (0.44)

0 (0)

0 (0)

Bacillariophyta

18.27 (2.33)

0 (0)

0 (0)

 Melosira varians

3.9 (1)

0 (0)

0 (0)

 Tabellaria fenestrata

2.37 (0.39)

0 (0)

0 (0)

 Diatoma elongatum

3 (0.48)

0 (0)

0 (0)

 Navicula sp.

2.87 (0.44)

0 (0)

0 (0)

 Gomphonema constrictum

2.47 (0.46)

0 (0)

0 (0)

 Cocconeis placentula

2.93 (0.56)

0 (0)

0 (0)

Other Diatom species

0.73 (0.21)

0 (0)

0 (0)

Roots, rhizomes and tubers of vascular submerged and coastal plants

6.7 (3.15)

11.20 (3.71)

52.83 (6.3)

 Phragmites australis

4.63 (2.01)

4.43 (1.15)

45.97 (6.51)

 Bolboschoenus maritimus

2.07 (1.19)

0.27 (0.19)

2.4 (1.85)

 Schoenoplectus tabernaemontani

0 (0)

0.83 (0.42)

1.67 (0.69)

 Agrostis sp.

0 (0)

0.57 (0.4)

0.53 (0.37)

 Calamagrostis sp.

0 (0)

0 (0)

0.03 (0.03)

 Phalaris arundinacea

0 (0)

1.33 (1.33)

0.33 (0.33)

 Carex sp.

0 (0)

1 (0.69)

0.48 (0.25)

 Eleocharis palustris

0 (0)

0 (0)

0.42 (0.34)

 Stuckenia pectinata

0 (0)

2.77 (2.43)

1 (0.84)

Vegetative parts of vascular submerged and coastal plants

13.5 (3.66)

25.73 (7.44)

32.73 (6.07)

 Phragmites australis

0 (0)

5.5 (3.49)

12 (3.88)

 Bolboschoenus maritimus

0 (0)

0 (0)

1.33 (0.76)

 Schoenoplectus tabernaemontani

0 (0)

2.33 (1.59)

0.17 (0.17)

 Agrostis sp.

0.7 (0.35)

0 (0)

0 (0)

 Phalaris arundinacea

0 (0)

0.17 (0.17)

0 (0)

 Carex sp.

0 (0)

0.33 (0.23)

0 (0)

 Alisma plantago-aquatica

0 (0)

0 (0)

0.07 (0.07)

 Eleocharis palustris

0 (0)

0 (0)

0.17 (0.17)

 Butomus umbellatus

0 (0)

1 (0.5)

0.23 (0.18)

 Sparganium sp.

0 (0)

3.33 (1.75)

3.67 (1.64)

 Sagittaria sagittifolia

0 (0)

0.17 (0.17)

4.33 (2.14)

 Nuphar lutea

0 (0)

4.5 (2.19)

5.5 (2.25)

 Hydrocharis morsus-ranae

0 (0)

0 (0)

0.27 (0.19)

 Zannichellia palustris

6.93 (2.19)

0.23 (0.18)

0 (0)

 Myriophyllum heterophyllum

0 (0)

0.5 (0.5)

0 (0)

 Stuckenia pectinata

5.73 (1.7)

6.27 (2.31)

4.23 (1.61)

 Potamogeton perfoliatus

0.13 (0.08)

1.40 (0.58)

0.77 (0.4)

Detritus

9 (3.24)

8.83 (3.21)

0 (0)