Acrocephalus 110 - lll.qxd  19.12.2002  11:02  Page^HB
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Acrocephalus 23 (110-111): 35 — 37, 2002
The actual status of Slender-billed Gull Larus genei on the southern Dalmatian coast
Status zalivskega galeba Larus genei na ju`nodalmatinski obali
Borut Rubinic , Luka Bozic  & Peter Sackl
Pra`akova 11, SI - 1000 Ljubljana, Slovenia, e-mail: rubinic@siol.net Pintarjeva 16, SI - 2106 Maribor, Slovenia, e-mail: luka.bozicwsiol.net
3 F          ,                  ..         "T.            nI     •       T T      r"            F                     •   1        /     T        J                             T
rorschungsstätte   Pater Blasius rianf   am rurtnerteich, c/o Landesmuseum Joanneum, Raubergasse 10, A - 8010 Graz, Austria, e-mail: peter.sackl@stmk.gv.at
The Slender-billed Gull Larus genei inhabits a discontinuous breeding range from the inland seas of Central Asia to the Caspian and Black Sea area. In the western parts of its range the species breeds more locally throughout the Mediterranean, southwards to the W. African coast in Mauretania and Senegambia. Whereas southern populations are largely resident, with limited dispersal, large numbers from the Black Sea area winter in the E. Mediterranean northwards to the Ionian Sea off W. Greece, the Strait of Otranto and S. Albania (Cramp 1983, Handrinos & Akriotis 1997)- Since the 1960s, in the course of an overall increase of eastern populations, the species established new breeding colonies in Sardinia, S, France and S, Spain (Serebryakov & Zubakin 1997) as well as in Valli di Comacchio (since 1978), Valle Bertuzzi (1987) and Margherita di Savoia (1988) on the Italian side of the Adriatic Sea (Boldreghini et al. 1989, Fasola & Brichetti 1993).
Despite its status as an established breeder away from its immediate nesting areas, Slender-billed Gulls are recorded only occasionally throughout the N. and E. Adriatic. Since 1945, there have been only 2 accepted records for Slovenia, with a total of 2 birds – April 11    1990 in Hotinja vas (Vogrin 199°)» and
March 10th – April 7 1991 in Se~oveljske soline (Jančar & Kmecl 1992, Božič 2001). In other republics of former Yugoslavia, Sage (1966) recorded the species in 1964 on Lake Prespa in S. Macedonia. In Croatia, according to I. Tutman, two Slender-billed Gulls were killed during the 1970s in the surroundings of Dubrovnik (Kralj 1997)- Although one of these birds is said to be preserved in the ornithological collection of the Dubrovnik Museum, neither origin nor date of collection for the specimen is documented (Kralj 1997, Lukač & Baltic 2001). Nevertheless, based on this record, Lukač (1998) included Slender-billed Gull in his most recent list of Croatian birds, as a rare visitor for the region.
During about 10 ornithological excursions to the S. Dalmatian coast since 1997 we saw the species on five occasions in the estuary of the Neretva river, near the harbour of Plo~e (Neretva delta). The bird faunas of the lower Neretva were studied intensively, by long-term recording and collecting, by Rucner (1993) in the last century. In contrast to Rucner, who does not mention the species for the area, we could record the species repeateatly in the delta since the late 1990s (Table 1). During our first observation in 1997 and again in late April 2001, we managed to take a series
Table 1 Observations of Slender-billed Gulls Larus genei in the Neretva estuary between 1997 and 2002 Tabela 1: Opazovanja zalivskega galeba Gulls Larus v delti Neretve med letoma 1997 in 2000
Date / Datum
No. of individuals / Št. osebkov
Age / Starost
Observers / Opazovalci
October 2nd 1997 April 29th 1998 May 1st 1998 April 27th 2001 May 5th 2002
ad. winter ad. summer ad. summer ad. summer ad. summer
B. Rubini~ B. Rubini~ B. Rubini~ L. Bo`i~, P. Sackl B. Rubini~
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B. RubiniČ et. al.: The actual status of Slender-billed Gull Larus genei on the southern Dalmatian coast
Figure 1: Adult winter Slender-billed Gull Larus genei resting on the water in the estuary of the Neretva river, S Dalmatia (Croatia), October 2nd 1997 (photo: B. Rubini~)
Slika 1: Odrasel zalivski galeb Larus geneiv zimskem perju po~iva na vodi v ustju reke Neretve, ju`na Dalmacija, 2.10.1997 (foto: B. Rubini~)
of photographs of the birds resting in the delta near the coast line at low tide (Figure 1 & Colour appendix - Figure 1). On almost all occasions, Slender-billed Gulls apparently stayed together, congregating while resting or feeding with Black-headed Larus ridibundus, Yellow-legged L. cachinnans and Mediterranean Gulls L. melanocephalus, as well as small numbers of Sandwich Terns Sterna sandvicensis, on tidal mudflats and on low sandbanks along, or immediately off, the coast line. Furthermore, during migration, mixed flocks of waders fed or rested in close association with the Slender-billed Gulls.
Our observations from the Neretva delta fit well into the period of the main autumn (July – October) and return passages (March – early May) of the species in the E. and central Mediterranean (Cramp 1983, Flint & Stewart 1983, Iapichino & Stewart 1989, Hadrinos & Akriotis 1997). It is not possible to decide, without further evidence, whether the birds we recorded on the lower Neretva since 1997 belong to breeding colonies on the Italian side of the Adriatic or if they constitute a fraction of vagrant migrants entering the N. Adriatic Sea outside the breeding season. Nevertheless, according to the very limited evidence for the occurrence of Slender-billed Gulls in the Neretva estuary (Rucner 1993) and elsewhere along the E Adriatic coast from the late 19 to 20 centuries   (Reiser  &  Führer 1896,   Reiser  1939,
36
Matvejev & Vasic 1973), the species appears to occur at present mainly as a rare visitor. Thus, our local results correspond quite well with recent increases of eastern populations (Heath et al. 2000). The species has established new breeding colonies in the W. Mediterranean, on the Italian coast of the Adriatic (approx. 1050 and 775 pairs in 1998 and 1999, respectively (F. Perco in lit.)), and is recorded more frequently in inland S. and W. Europe (Serebryakov & Zubakin 1997, Schmid et al. 2001).
Summary
The occurrence of Slender-billed Gulls Larus genei in Croatia was known by only a single record from the S Dalmatian coast. We report five new observations of the species for the area, in the estuary of the Neretva river near Plo~e between 1997 – 2002. We document our observations by photographs taken in the estuary in October 1997 and April 2001. In the course of long-term investigations during the last century on the birds of the lower Neretva, the species was not recorded. Thus, the more frequent occurence of the species as a rare migrant in the area during the late 1990s is apparently related to an overall increase of population numbers and the establishment of new breeding colonies on the Italian side of the Adriatic Sea.
Povzetek
Pojavljanje zalivskega galeba Larus genei na Hrva{kem je bilo znano le prek edinega podatka z ju`nodalmatinske obale. Navajamo pet novih opazovanj vrste za to obmo~je z izlivnega dela Neretve blizu mesta Plo~e med letoma 1997 in 2002, dokumentirana s fotografijami, posnetimi na ustju Neretve oktobra  1997 in aprila 2001   (slika  1   &
barvna priloga - slika 1). V ~asu raziskav ptic
spodnje Neretve zalivski galeb v teku 20. stoletja ni bil opazovan. Iz tega sklepamo, da je rednej{e pojavljanje vrste kot redke selivke na tem obmo~ju v ~asu poznih 90-ih let prej{njega stoletja povezano s splo{nim pove~anjem {tevil~nosti populacij in pojavom novih gnezditvenih kolonij na italijanski strani Jadrana.
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Prispelo / Arrived: 4.4.2002 Sprejeto / Accepted: 23.9.2002
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Acrocephalus 110 - lll.qxd  19.12.2002  11:02  Page^rS
barvna priloga / colour appendix
Figure 1: Slender-billed Gulls Larus genei resting together with Black-headed Gulls L. ridibundus and Sandwich Terns Sterna sandvicensis on low sandbanks in the Neretva estuary during low tide, April 27th 2001 (photo: P.Sackl) - see page 36
Slika 1: Po~ivajo~i zalivski galebi Larus genei v dru`bi re~nih galebov L. ridibundus in kri~avih ~iger Sterna sandvicensis na polojih v ustju reke Nertve med oseko, 27.4.2001 (foto: P. Sackl) - glej str. 36
Slika 2: Tur{ka kotorna Alectoris chukar, hrib Marijin Vijenac nad delto Neretve (J Dalmacija), 30.4.2001 (foto: J. Smole) - glej str. 56
Figure2: Chukar Partridge Alectoris chukar, Marijin Vijenac hill over the Neretva delta (S Dalmatia), April 30th 2001 (photo: J. Smole) - see page 56
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