BRANTA — Svetla Y. Dalakchieva
Breeding biology of waders order Charadriiformes (families Haematopodidae, Recurvirostridae, Burhinidae, Glareolidae and Scolopacidae) nesting along the Bulgarian Black Sea coast
Institution: Academy of Sciences, Sofia, Bulgaria
Supervisors: D Nankinov
Details: PhD 2004(Completed)
Address: Bulgarian Ornithological Centre, Institute of Zoology, BAS, Boul. 'Tzar Osvoboditel! 1, Sofia 1000, Bulgaria (Jan 2006) Email
Subject Keywords: Breeding biology, waders, Bulgaria
Species Keywords: Eurasian Oystercatcher Haematopus ostralegus, Black-winged Stilt Himantopus himantopus, Pied Avocet Recurvirostra avosetta, Stone-Curlew Burhinus oedicnemus, Collared Pratincole Glareola pratincola, Northern Lapwing Vanellus vanellus, Little Ringed Plover Charadrius dubius, Kentish Plover C. alexandrinus
Abstract
The Black Sea coast is a unique part of Bulgaria with many lakes, lagoons, salt-pans, rivers, rocks and dunes. This is the region of the country with the highest concentrations of wader species during the breeding season, as well as during migration and winter. For some species, this is the only area in the country where they breed.
The aim of the study was to investigate different aspects of the breeding biology of several wader species, which nest in various wetlands along the Bulgarian Black Sea coast. The main focus was mapping the location of breeding pairs and collecting various measurements in relation to the nests and eggs. Fieldwork covered the breeding seasons 2000-2003. Information was collected for eight species: Eurasian Oystercatcher Haematopus ostralegus, Black-winged Stilt Himantopus himantopus, Pied Avocet Recurvirostra avosetta, Stone-Curlew Burhinus oedicnemus, Collared Pratincole Glareola pratincola, Northern Lapwing Vanellus vanellus, Little Ringed Plover Charadrius dubius and Kentish Plover C. alexandrinus. A total of 1,736 nests were found and described and 6,319 eggs were measured.
In comparison with previous studies during 1977-1979, the number of breeding wader species was found to have decreased from 17 to the eight mentioned above. The most numerous breeding species was Pied Avocet (400-500 pairs), followed by Black-winged Stilt (70-105 pairs), Little Ringed Plover (100 pairs), Northern Lapwing (70-100 pairs), Kentish Plover (50-70 pairs), Collared Pratincole (16-30 pairs), Stone-Curlew (35 pairs) and Eurasian Oystercatcher (3-4 pairs). Over the past 20 years, numbers of Pied Avocets, Black-winged Stilts and Kentish Plovers have suffered a 4/5-fold decline and only Little Ringed Plovers have shown a major increase. The most important habitats for breeding waders are coastal lakes and beaches, followed by arable land, steppe habitats and wet meadows. All nests were classified according to their location and the arrangement of the building material. The eight species constructed nests in 18 different types of location, but most frequently they were built on open, flat surfaces. The building material was arranged in eleven different ways. Most frequently, nests were well-constructed scrapes with building material arranged evenly on the sides and bottom. Pied Avocet nests were the most varied. Sixty-two different types of building material were found in the nests of the eight species with dry twigs, grass stems, stones and small pieces of cinder being the most common. Several cases of intra- and interspecific nest-parasitism were recorded.
Waders breeding along the Bulgarian Black Sea coast are affected by many negative factors of which the most important are habitat degradation, predation and increased numbers of people. Conservation needs over the next few years include regular breeding population surveys as well as habitat monitoring and restoration.
Published Papers
Nankinov D. & Dalakchieva, S. 2001. State of the Stone Curlew Burhinus oedicnemus in Bulgaria. Russian Journal of Ornithology 152:603-613.
Nankinov D., Dalakchieva, S., Popov, K. & Kirilov, S. 2002. Die Geschichte der Rostflugel-Brachschwalbe Glareola pratincola in Bulgarien. Ornithologische Mittelungen 54 7/8: 234-242.
Dalakchieva S. 2002. Nest-sites and nest construction of the Little Ringed Plovers Charadrius dubius in Bulgaria. Wader Study Group Bulletin 98: 12-15.
Dalakchieva S. 2003. Nest location and nest-types of Avocet (Recurvirostra avosetta L.) in Bulgaria. Acta Zoologica Bulgarica 55 1:21-27.
Dalakchieva S. 2003. Changes in Breeding Population Numbers of Kentish Plover Charadrius alexandrinus at Atanasovsko Lake. Ornis Hungarica 12-13: 289-291.