We report herein on the results of the scientific monitoring of breeding populations, habitat use and the phenology of waterbird target species for the year 2019 under Action D1 of LIFE Prespa Waterbirds. The 2019 breeding season was marked by two events that significantly affected the condition of the reedbed and consequently the nesting of waterbirds. A heavy snowfall in November 2018 caused the reeds to recline, creating an unprecedented situation in the reedbed. This situation had a significant impact on waterbirds as the space available for nesting decreased dramatically. In addition, at the beginning of 2019, extensive fires that spread rapidly due to this irregular condition of the reedbed burned down a considerable area of 300 hectares. The lake level during the period April-May 2019 was between 854.03 and 853.98, which is even lower than that of 2017. As a result, shallow water areas on the outskirts of the lake were very few, 10-15 % of the total, compared to about 25% in 2017 and 50-60% in 2018.
The number of Dalmatian pelican breeding pairs was estimated at 1405 and breeding success at 0.74 young per br. pair, at similar levels to 2018. The number of great white pelican breeding pairs was estimated at 614 and the breeding success at a maximum of 0.70 young per br. pair.
As a consequence of the reedbed state in early 2019 the pygny cormorant and the herons sought alternative sites to nest, occupying various parts of the reedbed in the periphery or inside the lake, many of which were used for the first time. The restriction of the appropriate nesting area has led to the break-up of the colony into many smaller units. A total of nine discrete units were identified. Great white egrets appeared to be more affected by the limitation of traditional nesting sites. 2019 was the first time that a great white egret colony had been so much divided, into seven units. In all breeding units, a total of 2655 pygmy cormorant nests, 101 great white egret nests, 145 little egret nests, 265 night heron nests, 59 squacco heron nests were counted. No glossy ibis nest was detected. The great white egret breeding success was estimated in 2019 at 1.7 young per br. pair (n = 40), well below the one in 2018 and closer to that of 2017.
During the pre-breeding and breeding season 26 individuals of ferruginous duck were present in the northern part of Lake Lesser Prespa and the estimated number of breeding pairs was 4 to 12.
The results of the foraging sites monitoring showed that there were very few areas suitable for feeding given the low waterlevel in 2019. Total number of species observed in the sampling areas was low, though higher than in 2017, while average densities of all waterbirds in 2019 were even lower than in 2017 and less than half of those in 2018. However, in comparison to 2017, when there were hardly any managed areas, there were more birds in the areas managed in 2018 (even if observed in small numbers due to limited surfaces under management). This demonstrated clearly that the lower the waterlevel of the lake, the more vital becomes the increase of managed areas of reedbeds for the target waterbird species.
Action D1. Scientific monitoring of breeding populations habitat use and the phenology of waterbird target species for the year 2019