Златозар Боев [Zlatozar Boev]
27 December 1991 · volume 3
· pp. 75–91 · PDF [full text]
[no abstract available originally]
[Summary]: Data from literature, from museum collections throughout the Bulgaria, as well as unpublished material of Bulgarian and foreign ornithologists for the last 100 years are summarized constituting 216 observations of at least 949 specimens. Reported is a new nesting site of the species (islands on the Danube), the first one in North Bulgaria. The oystercatcher is a threatened species for Bulgarian bird fauna and generally a rare species throughout the country. Bulgaria is a peripheral area of its nesting range in Southeast Europe. The species occupies the range almost round the year, observations covering the period between February 14th and 31st of December. The majority of observations — 63,4% — were made during the breeding season. The winter months (November–February) comprise barely 2,8% of the occurrences of the species in Bulgaria, which shows that only separate individuals remain to winter around non-freezing basins as an exception. The main part of the migrants belong to the subspecies H. o. longipes, and actually, however rarely, H. o. ostralegus. Most probably the population .in the lower reaches of the Maritsa belong to the nominant subspecies with an Atlantic-Mediterranean distribution, while those nesting pairs along the Black Sea and Danubian coast line to the Siberian-East European subspecies H. o. longipes. Mating pairs have been registered in Bulgaria for the period 21st April–27th of July, egg laying period — 25th of April–15th of July, hatching of the young — 18th of May 27th of July. The maximum number of eggs established in nests is 4, those of the young in the clutch — 3. Nests are usually situated along open sandy beaches, close to the water. When nests are flooded, or the clutch is destroyed for other reasons, the pairs nest again. The largest groups of oystercatchers have been observed during the second half of July and in August. They usually number about 20–35 birds, the largest groups reaching above 80 oystercatchers. The first instance of Haematopus ostralegus nesting in Bulgaria was observed in 1973 in the middle reaches of the Maritsa river. In 1974 nesting was established in the middle reaches of the Tundzha river, in 1977 in the Atanasovsko Lake at the Black Sea coast, in 1982 along the lower reaches of the Maritsa, in 1987, in the Poda locality between the Mandrensko Lake and the Burgas Lake, and in 1989 on islands in the Danube. Judging from the common trends in the spread of the species in Europe, the process of oystercatcher penetration in the interior of the continent continues to this day on the Balkan Peninsula as well. For the past 17 years a total of 102 nesting pairs have been observed as the maximum numbers (about 50 pairs) during the 1982–1984 period. Seventy three oystercatchers have nested in Bulgaria during the past 6 years (1984–1989). A more massive spread is possible along the Danube, provided ecological conditions do not deteriorate.