Black-necked Grebe
Podiceps nigricollis (C. L. Brehm, 1831)
Colymbus nigricollis Brehm: Klain1909: 132; Podiceps caspicus Hablizl.: Patev, 1950: 256, Peshev, Boev, 1962: 260; Colymbus caspicus Hablizl.: Petrov, Zlatanov, 1955: 104.
Order Podicipediformes
Family Podicipedidae
Conservation status: in Bulgaria: Critically endangered CR=[A1a,c; B1a,c (iv); D], BDA-III; International: BeC-II.
General distribution. An Old World species. It breeds in a scattered fashion in Western and Central Europe, the southern half of the territory of Russia, Byelorussia, the Ukraine, Romania, Western Siberia, Kazakhstan, Mongolia, the Far East, Northeastern China, Asia Ninor, Iran, Iraq and Pakistan; in Africa – Kenia, Tansania and South Africa; the western parts of Northern America.
Distribution and abundance in Bulgaria. A rarely breeding summer visitor, a mainly passage migrant and wintering species. In the past, it mainly inhabited the larger marshes along the Danube and the Burgas Lakes [1, 2]. At present, singular pairs breed irregularly in the Srebarna reserve [3] and in the Kalimok fish farms near Tutrakan. The population abundance in the country does not exceed 40 breeding pairs. During migration it is found in the larger water basins in the whole country. It winters mainly along the Black Sea coast and the lakes near the shore, less frequently in the internal water basins of the country [2, 4]. For the period 1977-1996, the average numbers of wintering birds were 1 573 (517-3049) individuals, with a maximum in 1994; after 1996 the average numbers slightly increased and reached 2 130 individuals; the largest abundance was registered in Varna Lake – 1 030 individuals in the winter of 1998 [4].
Habitats. In the breeding period it prefers large freshwater lakes, fish farms with large separate basins, richly overgrown with vegetation, on which it builds its nests. In the winter it is close to the sea shore and in the shore lakes, less frequently in large, non-freezing freshwater basins, reservoirs, etc.
Biology. It breeds in colonies different in size; less often singularly. It usually forms mixed colonies with the Whiskered Tern. It builds a floating nest on the open water surface or on the overgrowth of Fringed Water-lily and Water Chestnut. It lays in May. The clutch contains 3-8 elongated white eggs. The young ones are nidifugous. After hatching the family resettles in another part of the water basin. The young ones become independent at the age of about 3 weeks [2]. Food: small fish, crustaceans, mussels, water plants, water insects and their larvae.
Similar species. The Slavonian Grebe (Podiceps auritus).
Negative factors. The abandoning of the existing fish farms along the Danube. The bad management and the impermanent water regime in the reserves Belene and Srebarna; the loss of the major microhabitat in the marshes of Belene – overgrowths with Fringed Water-lily and Water Chestnut necessary for the breeding of the Black-necked Grebe. Bulgaria is the southern border of the breeding area, hence its numbers have additional fluctuations, dependent on the state of the population in the rest of the territory.
Conservation measures taken. The major breeding habitats are in the reserves Belene and Srebarna.
Conservation measures needed. Restoration of the water regime in the Belene reserve and improvement of its state. Restoration of the Kalimok wetland and the fish farm in the village of Mechka, Ruse region. Improvement of the conditions in the Srebarna reserve by maintaining a high water level.
References. 1. Red Book of Bulgaria, 1985; 2. Simeonov et al., 1990; 3. Kambourova, 2005; 4. Michev, Profirov, 2003.
Author: Bozhidar Ivanov
