Vpliv plenilcev na talna in grmovna ptičja gnezda v antropogeno spremenjenih sonaravnih in urbanih okoljih

Rutnik, Katja (author), Kos, Ivan (mentor), Potočnik, Hubert (comentor)

Nizka uspešnost gnezdenja, kot posledica visoke stopnje plenjenja v urbanem, suburbanem območju ter odprti kulturni krajini, pomembno vpliva na populacijsko dinamiko. Raziskave na takšnih območjih so pokazale, da so glavni plenilci ptice iz družine vran. Študija plenjenja talnih, grmovnih in drevesnih umetnih simuliranih gnezd je potekala v 2 gnezditvenih sezonah. Za lažjo identifikacijo plenilcev je bila četrtina (polovica) gnezd naključno opremljena s kamerami. Izkazalo se je, da je stopnja plenjenja sive vrane odvisna od okoljskih dejavnikov. V prvem poskusu v bližini deponije kljub dolgotrajni izpostavljenosti gnezd ni bilo zabeleženega plenjenja s strani sive vrane. Le-te so raje izkoristile že znan vir hrane. V drugem poskusu so bila gnezda izpostavljena v 3–5-dnevnem obdobju na urbanem območju in ob plenjenju premeščena na novo lokacijo. Stopnja plenjenja umetnih simuliranih gnezd je bila kmalu po izpostavitvi visoka (30–100 %), kar nakazuje na prisotnost učenja ob dolgoročni izpostavljenosti. V večji meri so plenile sive vrane 79 %, srake 18 %. V tretjem delu smo v izogib učenju izbrali 4 prostorsko ločena območja ter gnezda izpostavili za največ 5 dni. Stopnja plenjenja je v tem primeru znašala 25–75 %.

• Language: Slovenian
• Keywords: siva vrana/sraka/plenjenje simuliranih ptičjih gnezd/suburbano območje
• Work type: Master's thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2017
• PID: 20.500.12556/RUL-98173
• COBISS.SI-ID: 4489807
• Publication date in RUL: 21.11.2017

RUTNIK, Katja, 2017, Vpliv plenilcev na talna in grmovna ptičja gnezda v antropogeno spremenjenih sonaravnih in urbanih okoljih [online]. Master’s thesis. [Accessed 14 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=98173

Secondary language

• Language: English
• Title: The impact of predation on ground and shrub bird nests in anthropogenically changed sustainable and urban environements

Abstract

Studies of ground-, shrub- and tree-nesting birds stress the importance of high nest losses as a factor influencing population dynamics. We conducted a two-season predation study with three field experiments, using artificial ground, shrub and tree nests simulating songbirds' nests as well as nests of ground-nesting galliformes and other tree-nesting birds. A portion of randomly selected nests have been monitored with camera-traps to identify predators. The results of predation experiments showed that predation rate on bird nests by the hooded crow depend on different environmental factors. In the first experiment near a city landfill site, where large numbers of crows were feeding, we didn't detect any case of nest predation by the hooded crow. It seems that crows are focused on feeding upon known sources of food at such locations. In the second experiment in the urban area predation increased markedly after exposure to artificial nests ranged from 30 to 100 % (predominantly by hooded crows – 79 % and Eurasian magpies – 18 % of predated nests), indicated that crows have detected (learned about) the increased food source in the area. In the third experiment artificial shrub and tree nests were set on different locations in open sub-urban landscape and exposed in short periods only (5 days) in order to minimize the potential learning of crows. Total predation rates by hooded crows in that experiment ranged from 25 % to 75 %.

• Keywords: hooded crow/magpie/artificial nests predation/suburban landscape