Dejan Bordjan (Author), Matej Gamser (Author), Aleksander Kozina (Author), Jure Novak (Author), Mitja Denac (Author), Aleksander Kozina (Photographer)

Abstract

Several bird species utilize artificial structures for communal roosting. Between 26 May and 28 Jun 2012, the selection of buoys and times of departure by Mediterranean Shags Phalacrocorax aristotelis desmarestii were studied at three communal roosts within shellfish farms in the Bays of Sv. Jernej (Debeli rtič), Strunjan and Piran (Sečovlje). A total of 3,110 buoys were counted and categorized into two groups according to their shape (horizontal and vertical) and colours. The black horizontally floating buoys were of two types (barrelshaped and oval). The Shags chose to utilize the horizontally floating buoys only, most often black and white in colour. Owing to their poorer stability and smaller standing surface, the vertically floating buoys are clearly unsuitable for them. The highest share of Shags with regard to the number of buoys of separate types was registered on black barrel-shaped buoys. As the percentage of occupied buoys was similar at all roost sites (36–39%), it was deduced that Shags distribute evenly among roosts, regardless of the number of individuals present in the Slovenian sea. At the larger roost at Debeli rtič, the percentage of adult individuals (73.5%) was greater than at Strunjan (42.5%). This could be due to the competition for better places, given that competitively stronger individuals select safer larger roosts. Between 5.42 and 9.00 hrs, 53.3% and 69.1% of Shags departed from the roost sites at Debeli rtič and Strunjan, respectively, with the majority of departures recorded between 7.50 and 8.30 hrs. They left their roosts mostly individually (48.7%) or in pairs (23.3%), at Debeli rtič predominantly in the SW (58.9%) and W (16.9%) directions, and at Strunjan in the NE (42.3%) and N (38.5%) directions.

Keywords

sredozemski vranjek;Phalacrocorax aristotelis desmarestii;prenočišče;boje;slovensko morje;Mediterranean Shag;roost-site;buoys;Slovenian coast;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: NIB - National Institute of Biology
UDC: 591
COBISS: 31306969 Link will open in a new window
ISSN: 0351-2851
Parent publication: Acrocephalus
Views: 26
Downloads: 22
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Other data

Secondary language: Slovenian
Secondary title: Značilnosti prenočišč sredozemskega vranjeka Phalacrocorax aristotelis desmarestii v slovenskem morju
Secondary keywords: sredozemski vranjek;Phalacrocorax aristotelis desmarestii;prenočišče;boje;slovensko morje;
URN: URN:NBN:SI
Type (COBISS): Not categorized
Source comment: Soavtorji: Matej Gamser, Aleksander Kozina, Jure Novak, Mitja Denac; Besedilo v angl.;
Pages: str. 5-11
Volume: ǂLetn. ǂ34
Issue: ǂšt. ǂ156/157
Chronology: 2013
ID: 24644252