Izvorni znanstveni članak
https://doi.org/10.21857/y54jofk34m
The long-term trend, reproductive performance and colony shifting of the Eurasian Griffon Gyps fulvus in Croatia
Goran Sušić
orcid.org/0000-0002-3036-3510
; Ornitološka postaja Rijeka, Zavod za ornitologiju, Hrvatska akademija znanosti i umjetnosti, Rijeka, Hrvatska
Sažetak
The Eurasian Griffon population in Croatia declined during most of the 20th century. Here the results related to the population trend and reproduction parameters and phenomena called colony shifting based on a 40-year research (1981 – 2021) are presented. The population declined from about 110-150 pairs in 10 colonies in 1981 to 78-95 pairs in 6 colonies in 1999, and subsequently increased to 141-150 pairs in 6 colonies in 2013. Since 1999, there have been no Griffons nesting in Paklenica, and it is possible that they all shifted to Kvarner, where 13% increase was recorded in 2000. In 2021, the total number was about 120 pairs on 5 islands: Cres, Plavnik, Krk, Prvić and Pag. Population density was estimated at 32.5 adult individuals/100 km2 and 13.75 breeding pairs/100 km2. Detailed population surveys were conducted during 15 years (2000 – 2014) to document cliffs’ saturation/occupancy, inter- and intra-colony nest movements, and for 10 years, to calculate reproductive arameters:
breeding success Bs = 0.60 ± 0.059 and productivity Pd = 0.55 ± 0.054. The nest site occupation was very low (M = 15.05%), implying that carrying capacity was not determined by cliff availability, and population is still far from saturation level. Six Kvarner islands’ colonies are functionally one single colony with many nest-clusters on the same or on different islands, annually pulsating with numbers of active nests on cliffs and regularly shifting from cliff to cliff and back.
Ključne riječi
population status; reproductive parameters; coloniality; nest-site movements; vultures
Hrčak ID:
274242
URI
Datum izdavanja:
23.3.2022.
Posjeta: 695 *