Great Crested Grebe
Podiceps cristatus Linnaeus, 1758
Order Podicipediformes
Family Podicipedidae
Conservation status: in Bulgaria: Vulnerable VU=B[1(biii)]+C+C[2(a(i)b(iv))]+D[1], BDA-III; International: BeC-III.
General distribution. A species of the Old World. It is found in the temperate and southern parts of Europe, Asia, Africa, Australia and New Zealand. The European population is estimated at 580 000 – 870 000 pairs [1].
Distribution and abundance in Bulgaria. A breeding summer visitor, passage migrant and winter visitor. At the end of the 19th century it bred throughout the country, then a depression followed and during the first half of the 20th century it inhabited only the Danubian and the Black Sea coast; after the 1960s it increased its numbers by settling water basins also within the country with a total of about 30 breeding places [2]. At present, it incubates along the Danubian and the Black Sea coast, the Danube valley, the Sofia field, the valleys of the rivers Maritsa and Tundzha with total numbers 800 – 1 000 [3], 400-600 breeding pairs [4]. In the winter, the numbers are many times larger, especially in the Black Sea wetlands and the non-freezing water basins of Southern Bulgaria. The average winter numbers for the 1977-96 period was 2 192 individuals [5]. In 1980 along the Black Sea coast and the wetlands around it, record numbers of 12 031 individuals were registered [5].
Habitats. Freshwater water basins, fish farms and microreservoirs. It prefers water basins, overgrown in a ring-like fashion with a wide but not very thick section of rush or reed; in the winter – large freshwater lakes, reservoirs, lagoons and shallow sea bays.
Biology. The breeding section has an area of 350 - 500 m2 in singular breeding and 50 - 150 m2, in colonial breeding; the period of laying the eggs is extended from the end of April to the end of August; the clutch contains 2-6 eggs [6]. It feeds on fish, frogs, crustaceans, coelenterates, water insects and their larvae, water plants.
Similar species. None.
Negative factors. Destruction of the overgrowths of reed and rush in freshwater fish farms and the reduction of their numbers. Purposeful killing by lessees of water basins. Abrupt changes of the water level in freshwater fish farms and reservoirs during the breeding period.
Conservation measures taken. Protected according to the Biological Diversity Act. A considrebale part of the breeding places are included in the Natura 200 protected zones.
Conservation measures needed. Measures must be envisioned in the future Management Plans of the territories included in Natura 2000 against killing and disturbance of the breeding birds by lessees of fish farms and microreservoirs.
References. 1. Wetlands International, 2006; 2. Simeonov et al., 1990; 3. Nankinov et al., 2004; 4. Iankov (in press); 5. Michev & Profirov, 2003; 6. Nikolov et al., 1986.
Author: Hristo Nikolov
