Winter ecology of great grey shrike, Lanius excubitor (Aves: Laniidae)

V letih 2000–2013 smo izvedli raziskavo biologije zimske populacije velikega srakoperja (Lanius excubitor), na območju Dravskega in Ptujskega polja. V časovnem oknu 13 let smo opravili 144 terenskih popisov na 12 popisnih območjih (Dravsko in Ptujsko polje smo razdelili na 12 manjših območij). Z uporabo metode štetja na površini (neposredno štetje vseh osebkov ciljne vrste na izbranem območju) smo zabeležili 424 osebkov. V sklopu raziskave smo ugotavljali povezavo med številčnostjo velikih srakoperjev in klimatskimi spremenljivkami, testirali prostorsko avtokorelacijo v številu osebkov med območji, določili zgostitve osebkov, ugotavljali povezavo med velikostjo območja in številom srakoperjev, opisali prehranjevalni habitat, ter analizirali lovne strukture in prehrano velikega srakoperja. Dobljeni rezultati izkazujejo, da variabilnosti v številu srakoperjev ni mogoče pojasniti s klimatskimi dejavniki. Zgostitve srakoperjev so bile povezane s strukturiranostjo habitata. Na gostoto osebkov je vplivala raba prostora in ne površina prehranjevalnega habitata. Srakoperji so za prehranjevalni habitat izbirali polja s krajinskimi rekviziti (grmi, drevesa, električnimi vodniki itd.). V prehrani so prevladovali vretenčarji. Kmetijsko okoljski ukrepi niso zadostni za dolgoročni obstoj populacije velikega srakoperja.In the years 2000 to 2013 the first research of many years standing about biology winter population of a great grey shrike was carried out on the region of Dravsko and Ptujsko polje. Within the 13 years time window 144 field surveys on 12 regions were done (extensive Dravsko and Ptujsko polje were divided into 12 smaller regions). There were 424 specimen recorded. The method of counting on the area was used, which includes counting all the specimen of target species directly on the chosen area. As a part of the research we determined the relationship between the numerosity of great grey shrikes and climate variables, tested spatial autocorrelation, determined the density of individuals and the relationship between the area size and the number of shrikes, studied food habitat and analysed hunting structures and the diet of a great grey shrike. Survey results indicate that the variability in the number of great shrikes can not be explained with climatic factors. Greater density of great shrikes was connected to to bigger habitat structuring. The use of environment and microstructures had the influence (effect) on the density and not the feeding habitat area. In our research shrikes preferentially chose fields with landscape structures (such as bushes, trees, electric lines etc.) for their feeding habitat. Vertebrates prevailed in shrikes\u27 diet. Agri-environmental measures are not sufficient for the long-term existence of a great shrike, because they do not ensure conservation of the species in the long run