Nest‐site habitat selected by Short‐toed EaglesCircaetus gallicusin Dadia Forest (northeastern Greece)

Abstract

Data concerning habitat characteristics and general physiographic characteristics at 29 Short‐toed Eagle Circaetus gallicus nest‐sites (circular plot of 0.4 ha centred on the nest tree) were collected and compared with the same number of paired randomly selected plots in Dadia‐Lefkimi‐Soufli forest complex, northeast Greece. Short‐toed Eagles used southern slopes for nesting and nest‐sites were often located on the upper third of each slope. Nest trees were found significantly closer to rain water gullies, to the boundary of a different habitat type, and to the nearest forest opening greater than 0.5 ha than the randomly selected nest trees. Nest‐sites had a significantly lower mean score of human disturbance than random sites and were found in mature pine forest associations, dominated by Calabrian Pine Pinus brutia or Black Pine P. nigra. The total tree density of Short‐toed Eagle nest‐sites was lower than random sites. Canopy cover in the dominant and intermediate tree layer at nest‐sites was lower than at random sites. Short‐toed Eagles tended to select sites for nesting that provided a combination of easy access and maximum shelter of the nest content from predators and inclement weather. The preservation of open structure of mature pine stands on south facing slopes near clearings may be critical for the continued conservation of the Short‐toed Eagle in actively managed forests, such as the Dadia‐Lefkimi‐Soufli forest complex.

Description of the Short-toed Eagle Circaetus gallicus breeding cycle at two sites in SW Slovenia during the years 2010 and 2011

“…Nekateri avtorji ugotavljajo, da so takšni primeri pri kačarju redki; Petretti (2008) navaja, da je par kačarjev od 39 spremljanih gnezdenj v osrednji Italiji isto gnezdo v dveh zaporednih letih uporabil le v dveh primerih, v treh zaporednih letih pa le v enem primeru. Bakaloudis et al (2000) so v svoji raziskavi v SV Grčiji prišli do podobnih rezultatov: v 35 gnezdenjih je sedem parov popravilo in ponovno uporabilo isto gnezdo v dveh zaporednih letih, medtem ko so le trije pari isto gnezdo uporabljali več kot dve leti. Nasprotno pa Cramp (1980) navaja, da kačar pogosto vnovič uporabi isto gnezdo, čeprav ne nujno v zaporednih letih.…”

“…Tudi sicer kačar gnezdi pretežno na odraslih iglavcih, navadno 3-14 m nad tlemi, na stranskih vejah, pogosto pa tudi v vrhu krošnje drevesa (Bakaloudis et al 2000, Campora & Cattaneo 2006, Petretti 2008. Za kačarja sta pri izbiri lokacije zelo pomembni tako dostopnost gnezda iz zraka kot običajna smer prileta oziroma odleta (Bakaloudis et al 2000). Izbira vrste gnezditvenega drevesa je odvisna od geografskega območja.…”

“…Izbira vrste gnezditvenega drevesa je odvisna od geografskega območja. V Grčiji kačar za gnezdenje izbira turški bor Pinus brutia (83 %) ter črni bor Pinus nigra (17 %) (Bakaloudis et al 2000). V italijanskih Alpah je 83 % kačarjevih gnezd lociranih na iglavcih, med njimi sta tudi macesen Larix decidua (17 %) in smreka Picea abies (16 %).…”

“…Prednostna izbira iglavcev za gnezdenje je razvidna tudi iz izbire manjšega sestoja črnega bora na vipavski lokaciji, ki je sicer del obsežnih, pretežno listnatih gozdov s prevladujočimi hrasti Quercus spp. Premer debel dreves z najdenimi gnezdi kačarja v JZ Sloveniji v letih 2010 in 2011 je v povprečju 40 cm, kar je nekoliko manj od rezultatov drugih avtorjev, konkretno 43,5 cm (Vlachos & Papageorgiou 1994) oziroma 49,7 cm (Bakaloudis et al 2000), ustreza pa navedbam o izbiri odraslih dreves za gnezdenje.…”

Systematic Raptor Monitoring as conservation tool: 12 year results in the light of landscape changes in Dadia-Lefkimi-Soufli National Park

“…The Short-toed eagle is a specialist predator with a narrow niche diet of reptiles (Bakaloudis 1998), along with specific habitat needs for nesting (Bakaloudis 2001). Within the NP, forests have begun encroaching on abandoned agricultural land, increasing the extent of closed canopy (Adamakopoulos 1995) and negatively impacting biodiversity (Zakkak 2014).…”