Numbers of wintering waterbirds in the Czech Republic: long-term and spatial-scale approaches to assess population size

Figures & data

Figure 1. Distribution of wetland sites investigated in 1982–85 (solid circles) and investigated in other years between 1966 and 2013 (open circles) in the Czech Republic. The grid of squares represents squares used by AWB (12 km × 11.1 km in size). Grey squares were not investigated.

Figure 2. Illustration of the calculation of overlap proportion for Goosander.

Table 1. National population size estimates of wintering waterbirds based on data gathered as part of the IWC and AWB between 1982 and 1985 (mean and max values across the four years).

Common name	Species	IWC	AWB	Overlap	Late-departing/early-arriving migrants
Mute Swan	Cygnus olor	3800–4400	2900–4000	1	0
Tundra Swan	Cygnus columbianus	0	0–3	0	1
Whooper Swan	Cygnus cygnus	6–6	0–15	1	1
Bean Goose	Anser fabalis	960–1800	20 000–40 000	0	1
Pink-footed Goose	Anser brachyrhynchos	0	0–12	0	1
White-fronted Goose	Anser albifrons	15–35	400–800	0	1
Lesser White-fronted Goose	Anser erythropus	0	0–1	0	1
Greylag Goose	Anser anser	80–130	400–900	0	1
Canada Goose	Branta canadensis	0	0–5	0	1
Barnacle Goose	Branta leucopsis	0–1	0	0	1
Common Shelduck	Tadorna tadorna	0	0–1	0	1
Wood Duck	Aix sponsa	0–1	0–1	1	1
Eurasian Wigeon	Anas penelope	40–45	10–50	1	1
Gadwall	Anas strepera	3–9	50–100	0	1
Common Teal	Anas crecca	1100–1400	1200–2500	1	1
Mallard	Anas platyrhynchos	133 000–155 000	100 000–300 000	1	1
Northern Pintail	Anas acuta	9–10	5–14	1	1
Garganey	Anas querquedula	0	0–10	0	1
Northern Shoveler	Anas clypeata	4–7	10–60	0	1
Red-crested Pochard	Netta rufina	1–2	1–15	1	1
Common Pochard	Aythya ferina	1500–1900	3000–7000	0	1
Ferruginous Duck	Aythya nyroca	7–20	1–5	0	1
Tufted Duck	Aythya fuligula	1000–1400	2500–5000	0	1
Greater Scaup	Aythya marila	9–10	5–15	1	0
Common Eider	Sommateria mollissima	0–1	2–10	0	1
Long-tailed Duck	Clangula hyemalis	4–5	2–10	1	0
Common Scoter	Melanitta nigra	0–2	0–5	1	0
Velvet Scoter	Melanitta fusca	3–10	8–20	1	0
Common Goldeneye	Bucephala clangula	590–650	500–1000	1	0
Smew	Mergellus albellus	15–25	30–60	0	1
Red-breasted Merganser	Mergus serrator	6–70	4–8	1	1
Goosander	Mergus merganser	1500–2600	800–2000	1	0
Red-throated Diver	Gavia stellata	0	2–10	0	1
Black-throated Diver	Gavia arctica	3–6	10–30	0	1
Great Northern Diver	Gavia immer	0	0–1	0	1
Little Grebe	Tachybaptus ruficollis	930–990	1000–2000	0	1
Great Crested Grebe	Podiceps cristatus	170–190	400–900	0	1
Red-necked Grebe	Podiceps grisegena	0–2	2–20	0	1
Horned Grebe	Podiceps auritus	0–1	1–15	0	1
Black-necked Grebe	Podiceps nigricollis	0–1	1–10	0	1
Great Cormorant	Phalacrocorax carbo	600–810	500–1500	1	0
Great Bittern	Botaurus stellaris	1–1	0–3	1	1
Night Heron	Nycticorax nycticorax	0	0–1	0	1
Great White Egret	Egretta alba	4–15	50–100	0	1
Grey Heron	Ardea cinerea	1100–1800	3000–6000	0	1
Black Stork	Ciconia nigra	0	0–1	0	1
White Stork	Ciconia ciconia	0	4–10	0	1
Glossy Ibis	Plegadis falcinellus	0	0–1	0	1
Water Rail	Rallus aquaticus	4–4	20–50	0	1
Common Moorhen	Gallinula chloropus	500–570	700–1500	0	1
Common Coot	Fulica atra	16 000–18 000	18 000–36 000	0	1
European Golden Plover	Pluvialis apricaria	0–1	0–3	1	1
Grey Plover	Pluvialis squatarola	0	0–1	0	1
Northern Lapwing	Vanellus vanellus	10–180	800–1600	0	1
Little Stint	Calidris minuta	0–1	0	0	1
Dunlin	Calidris alpina	0	0–10	0	1
Jack Snipe	Lymnocryptes minimus	0	0–2	0	1
Common Snipe	Gallinago gallinago	10–20	30–70	0	1
Eurasian Woodcock	Scolopax rusticola	0	0–3	0	1
Eurasian Curlew	Numenius arquata	0–1	0–20	1	1
Common Sandpiper	Actitis hypoleucos	0	0–5	0	1
Green Sandpiper	Tringa ochropus	15–20	40–100	0	1
Black-legged Kittiwake	Rissa tridactyla	0	2–15	0	1
Black-headed Gull	Larus ridibundus	10 000–17 000	80 000–140 000	0	1
Little Gull	Larus minutus	0–1	0–3	1	1
Common Gull	Larus canus	700–1900	600–1300	1	0
large gulls	Larus argentatus/cachinans	9–20	10–30	1	1
Great Black-backed Gull	Larus marinus	0	0–1	0	1
Western Marsh Harrier	Circus aeruginosus	0	0–5	0	1
Hen Harrier	Circus cyaneus	0–3	700–1500	0	1
Montagu's Harrier	Circus pygargus	0	0–1	0	1
White-tailed Eagle	Haliaeetus albicilla	10–15	40–80	0	0
Osprey	Pandion haliaetus	0	0–3	0	1
Common Kingfisher	Alcedo atthis	75–110	400–800	0	1
Meadow Pipit	Anthus pratensis	0	1500–3000	0	1
Grey Wagtail	Motacilla cinerea	7–8	500–1000	0	1
White Wagtail	Motacilla alba	0	700–1400	0	1
White-throated Dipper	Cinclus cinclus	290–340	1800–3500	0	0
Bearded Tit	Panurus biarmicus	0	0–60	0	1
Eurasian Penduline Tit	Remiz pendulinus	0	0–4	0	1
Reed Bunting	Emberiza schoeniclus	0–7	800–1600	0	1

Late-departing/early-arriving migrants coded as 1 and others (resident species) coded as 0.

Table 2. GLM analysis of effect of migratory strategy and of population distribution and population size on overlap between IWC and AWB population estimates for n = 81 species in all models. Distribution and population size obtained from IWC data in (a) and AWB data in (b); parameter estimates are presented with robust standard errors in parentheses; * P < 0.05, ** P < 0.01, *** P < 0.001.

	Overlap		Overlap proportion (AWB)		Overlap proportion (IWC)
	(a)	(b)	(a)	(b)	(a)	(b)
Migratory strategy	−3.07*** (0.86)	−3.45*** (0.80)	−1.87*** (0.50)	−2.15*** (0.53)	−2.20*** (0.67)	−2.63*** (0.63)
Distribution	−0.40 (1.20)	−1.16 (0.97)	−2.25 (1.20)	−1.02 (0.83)	0.30 (1.00)	−1.59 (0.92)
Population size	0.45 (0.60)	0.58 (0.59)	1.12 (0.60)	0.34 (0.47)	−0.10 (0.59)	0.75 (0.56)
Constant	1.20 (0.84)	2.18** (0.85)	−1.24*** (0.36)	−0.28 (0.66)	0.34 (0.68)	1.39 (0.76)

Table 3. Population size estimates according to data from the IWC between 2009 and 2013.

Common name	Species	Population size	1% Threshold
Mute Swan	Cygnus olor	3000–4000	35
Whooper Swan	Cygnus cygnus	0–15	0
Swan Goose	Anser cygnoides	0–1	0
Bean Goose	Anser fabalis	1100–14 000	70
Pink-footed Goose	Anser brachyrhynchos	0–3	0
White-fronted Goose	Anser albifrons	6000–58 000	240
Lesser White-fronted Goose	Anser erythropus	0–2	0
Greylag Goose	Anser anser	1900–5700	40
Bar-headed Goose	Anser indicus	0–1	0
Canada Goose	Branta canadensis	0–4	0
Barnacle Goose	Branta leucopsis	0–20	0
Red-breasted Goose	Branta ruficollis	0–6	0
Egyptian Goose	Alopochen aegyptiaca	0–8	0
Ruddy Shelduck	Tadorna ferruginea	0–3	0
Shelduck	Tadorna tadorna	0–1	0
Muscovy Duck	Cairina moschata	0–17	0
Ringed Teal	Callonetta leucophrys	0–2	0
Wood Duck	Aix sponsa	2–15	0
Mandarin Duck	Aix galericulata	0–36	0
Eurasian Wigeon	Anas penelope	100–160	1
American Wigeon	Anas americana	0–1	0
Chiloe Wigeon	Anas sibilatrix	0–1	0
Gadwall	Anas strepera	65–170	1
Common Teal	Anas crecca	460–690	6
Mallard	Anas platyrhynchos	162 000–194 000	1800
Northern Pintail	Anas acuta	10–15	0
Northern Shoveler	Anas clypeata	3–20	0
Red-crested Pochard	Netta rufina	0–6	0
Common Pochard	Aythya ferina	800–2000	15
Ferruginous Duck	Aythya nyroca	0–9	0
Tufted Duck	Aythya fuligula	4100–5800	50
Greater Scaup	Aythya marila	20–100	0
Common Eider	Sommateria mollissima	0–1	0
King Eider	Clangula hyemalis	0–6	0
Common Scoter	Melanitta nigra	0–3	0
Velvet Scoter	Melanitta fusca	15–115	0
Common Goldeneye	Bucephala clangula	850–1300	10
Great Smew	Mergellus albellus	70–120	0
Red-breasted Merganser	Mergus serrator	1–8	0
Goosander	Mergus merganser	2800–4000	35
Ruddy Duck	Oxyura jamaicensis	0–1	0
Red-throated Diver	Gavia stellata	0–4	0
Black-throated Diver	Gavia arctica	3–9	0
Great Northern Diver	Gavia immer	0–2	0
Little Grebe	Tachybaptus ruficollis	470–1000	7
Great Crested Grebe	Podiceps cristatus	140–260	2
Red-necked Grebe	Podiceps grisegena	0–1	0
Slavonian Grebe	Podiceps auritus	0–8	0
Black-necked Grebe	Podiceps nigricollis	0–2	0
Great Cormorant	Phalacrocorax carbo	10 600–14 100	120
Pygmy Cormorant	Phalacrocorax pygmeus	0–1	0
Great Bittern	Botaurus stellaris	1–7	0
Little Egret	Egretta garzetta	0–1	0
Great White Egret	Egretta alba	260–630	4
Grey Heron	Ardea cinerea	2000–3000	25
White Stork	Ciconia ciconia	0–3	0
Water Rail	Rallus aquaticus	1–5	0
Common Moorhen	Gallinula chloropus	390–800	5
Common Coot	Fulica atra	9200–12 800	110
Eurasian Crane	Grus grus	0–1	0
Northern Lapwing	Vanellus vanellus	9–20	0
Jack Snipe	Lymnocryptes minimus	0–1	0
Common Snipe	Gallinago gallinago	0–4	0
Green Sandpiper	Tringa ochropus	9–25	0
Eurasian Curlew	Numenius arquata	0–1	0
Black-headed Gull	Larus ridibundus	8300–10 500	95
Mediterranean Gull	Larus melanocephalus	0–1	0
Little Gull	Larus minutus	0–3	0
Common Gull	Larus canus	990–2900	25
Lesser Black-backed Gull	Larus fuscus	0–1	0
large gulls	Larus argentatus/cachinans	470–2500	10
Marsh Harrier	Circus aeruginosus	0–1	0
White-tailed Eagle	Haliaeetus albicilla	120–200	2
Osprey	Pandion haliaetus	0–1	0
Common Kingfisher	Alcedo atthis	80–250	2
Grey Wagtail	Motacilla cinerea	25–50	0
Pied Wagtail	Motacilla alba	15–35	0
White-throated Dipper	Cinclus cinclus	400–730	6
Bearded Tit	Panurus biarmicus	0–22	0