Davorin TOME

Nacionalni inštitut za biologijo, SI-1000 Ljubljana, Večna pot 111

E-mail: davorin.tome@uni-lj.si

IZVLEČEK

Prispevek opisuje avifavno šestih pivških jezer. Zaradi presihajočega značaja jezer na tem območju najdemo predvsem vrste, ki so značilne za kulturno krajino. Za gnezditev ptic sta pomembni le Petelinjsko in Palško jezero. Čeprav število gnezdečih parov posameznih vrst ni veliko, so gnezditvene gostote pisane penice (Sylvia nisoria), rjavega srakoperja (Lanius collurio) in velikega strnada (Miliaria calandra) med najvišjimi v Sloveniji. Visoke gostote dosegajo tudi prepelica (Coturnix coturnix), kosec (Crex crex) in rjava penica (Sylvia communis). Obe jezeri sta lahko referenčni območji za izračune potencialne velikosti populacij ptic v kulturni krajini notranjskega dela Slovenije.

Ključne besede: pivška presihajoča jezera, avifavna

SINTESI

L'articolo descrive l'avifauna dei sei laghi di Pivka. A causa del periodico dissecamento di tali laghi, nell'area troviamo soprattutto specie caratteristiche del paesaggio culturale. Per gli uccelli in periodo di nidificazione sono particolarmente importanti i laghi di Petelinje e Palčje. Sebbene il numero di coppie nidificanti di ogni singola specie non sia alto, le densità di nidificazione della bigia padovana (Sylvia nisoria), dell'averla piccola (Lanius collurio) e dello strillozzo (Milaria calandra) sono tra le più alte in Slovenia. Presentano valori alti di densità anche la quaglia (Coturnix coturnix), il re di quaglie (Crex crex) e la sterpazzola (Sylvia communis). Entrambi i laghi possono venir considerati stazioni di riferimento per il calcolo della grandezza potenziale delle popolazioni di uccelli nel paesaggio culturale della regione interna della Slovenia.

Parole chiave: laghi intermittenti di Pivka, avifauna

Davorin Tome

National Institute of Biology, SI-1000 Ljubljana, Večna pot 111

E-mail: davorin.tome@uni-lj.si

Summary

The present contribution deals with avifauna of the six Pivka lakes. Due to their intermittent character, however, largely birds typical of cultural landscape are found in the district. Only Petelinjsko jezero and Palško jezero are important as birds' breeding habitats. Although the numbers of separate species' breeding pairs are not high, the densities of the breeding Barred Warbler (Sylvia nisoria), Red-backed Shrike (Lanius collurio) and Corn Bunting (Miliaria calandra) are amongst the highest in Slovenia. High densities are also reached by Common Quail (Coturnix coturnix), Corn Crake (Crex crex) and Common Whitethroat (Sylvia communis).

In the articles dealing with the birds of cultural landscape, we are more and more frequently describing the changes that took place in the numbers of separate species' breeding pairs between the surveys carried out in several temporally distant periods. The assessed differences are normally used as a nature conservationist argumentation for the district's threat status. Quantitative surveys have been carried out in our country only in the last 5 or 10 years, when practically the entire Slovene cultural landscape has been strongly influenced by intensive human pressures. For an authentic recording of the changes as a result of intensive farming, however, data on the numbers of birds prior to the pressures being carried out would be needed. These values could be called potential population sizes, for they indicate the number of birds that could still breed in our country if the conditions were favourable enough. At least partly objective estimate as far as these sizes are concerned could be reached with the aid of the data on densities of the birds in lowly exploited districts that can still be found and surveyed here and there. The data on the birds of Petelinjsko jezero and Palško jezero can certainly be one of the reference values for the estimate of bird populations' potential sizes in cultural landscape in the Notranjska region of Slovenia.

Key words: Pivka intermittent lakes, avifauna