See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/265293744

Melanism and plumage variation in macroura Ural

Article in Dutch Birding · January 2009

CITATIONS READS 5 1,813

1 author:

Al Vrezec National Institute of Biology - Nacionalni inštitut za biologijo

159 PUBLICATIONS 959 CITATIONS

SEE PROFILE

Some of the authors of this publication are also working on these related projects:

Slovenian Ringing Center View project

Ornithological museum collection View project

All content following this page was uploaded by Al Vrezec on 03 September 2014.

The user has requested enhancement of the downloaded file. Melanism and plumage variation in macroura Ural Owl

Al Vrezec

ral Owl uralensis is a northern boreal macroura and are therefore regarded as synonyms Uspecies with a large continuous Palearctic (Kohl 1977, cf König et al 1999). The Chinese breeding range extending from in population is also treated as a single subspecies, the west across to the Pacific coast of S u davidi (hereafter davidi) and, in recent taxo- , and in the east. According to nomic studies, has been regarded as a separate fossil remains, it was more widespread in glacial species, Sichuan Wood Owl S davidi (eg, del Hoyo times (eg, Scherzinger 2006). Today, there are at et al 1999, König et al 1999), although morpho- least three isolated southern populations regarded logical and bioacoustic studies did not support as glacial relicts which are clearly distinguished specific separation from Ural Owl (Scherzinger & from the northern in size and morphology: Fang 2006). Japanese Ural are the smallest in central and south-, in China and and comprise c three recognized subspecies (cf in Japan. In the of central and south- del Hoyo et al 1999, König et al 1999): S u fusces- eastern Europe, the subspecies S u macroura (here- cens, S u hondoensis (including ‘momiyamae’) after macroura) occurs; the Carpathian S u ‘car- and S u japonica (König et al 1999 also include pathica’ and Central-European S u ‘sumaviensis’ japonica in hondoensis). The other, northern, sub- can not clearly be separated morphologically from species are nominate S u uralensis (eastern Russia;

Figure 1 Distribution of Carpathian-Dinaric Ural Owl Strix uralensis macroura according to currently available data (population in Bohemian on borders of , and is introduced)

[Dutch Birding 31: 159-170, 2009] 159 Melanism and plumage variation in macroura Ural Owl including ‘buturlini’); S u liturata ( birds collected may not be an even representation to the Baltic region, and east to the river; the of the different populations as collectors tend to statement in König et al (1999) that this subspecies pay more attention to aberrant or rare birds than occurs in ‘eastern and Carpathians’ is incor- to ‘normal’ birds. In the present study, I have rect); S u yenisseensis (); therefore estimated the proportion of the four col- and S u nikolskii (Transbaikalia north to Sachalin, our morphs in the (sub)population of macroura in Russia, and south to Korea; including ‘daurica’, in the wild. To get unbiased proportion ‘tatibanai’ and ‘coreensis’). estimations, I have included the following data One of the characteristics of the isolated sub- into the study: 1 museum skins (only birds that species macroura are the dark or almost black in- were found dead in the field, ie, by passive col- dividuals that occur sporadically over the whole lecting); 2 data from breeding biology studies in range from the Carpathian mountains to the the field; and 3 photographs taken in the wild Dinaric Alps (Kohl 1977). This feature appears to with location details given. be unique for this subspecies since no such dark In this paper, a new up-to-date distribution map individuals have been reported from other parts of of macroura is given. The map is based on recent- the range of Ural Owl. ly published data but also some overlooked stud- The melanistic individuals found relatively fre- ies from the southern Dinaric part of the distribu- quently in macroura have only been treated brief- tion were included, especially in former Yugoslavia ly in the context of taxonomic differentiation from (Reiser 1939, Obratil 1977, Pietiäinien & Saurola other Ural Owl subspecies (eg, Kohl 1977, 1997, Rašajski & Vuc̆anović 1998, Tomiałojc̆ & Mikkola 1983, König et al 1999). The overall col- Stawarczyk 2003, Novcˇ ić 2004, Vrezec & Tutiš our variability, including the gradient of colour 2003, Feldner et al 2006, Genero & Benussi 2007, morphs from pale to melanistic, has not yet been Krištin et al 2007, Lukac̆ 2007, Vrezec 2007). studied in detail. As a consequence, there is still very little data available about this subject. The Population and distribution of macroura aim of this paper is to review current knowledge According to the most recent estimations, the about the plumage variation in populations of population size of macroura is 4200-6500 breed- macroura, with special emphasis on melanism. ing pairs (cf Mebs 2007). The northernmost part of the breeding range is southern from where Material and methods it is distributed across the Carpathian mountains This paper presents a review of current knowledge to the south-east. In , Ural Owl is still of colour morphs and more specifically of melan- common but further south and west it becomes ism in macroura, including results of previous scarcer. In and , it published studies and additional studies of muse- is currently considered to be rare. The status is un- um skins at the Slovenian Museum of Natural certain in Greece, Macedonia and Montenegro. History in , Slovenia, birds found dead, The taxon is common in and Slovenia field studies in a breeding population in Slovenia, (Vrezec & Tutiš 2003). The westernmost part of the and on photographic material collected in distribution is in north-eastern and southern Slovenia. The plumage coloration variation was Austria, where a few pairs have been found re- established by studies of museum skins and dead cently (Feldner et al 2006, Genero & Benussi birds as well as numerous photographs, from 2007). In the Bohemian Forest covering parts of which also the drawings of the four colour morphs Austria, the Czech Republic and Germany, Ural (figure 2) were prepared. For the whole range of Owl became extinct in 1926 but reintroduction macroura, rough estimations of the proportion of took place from 1970 onwards (Scherzinger melanistic owls in the population based on mu- 2006). Since the core area of macroura is con- seum collections have been published (eg, fined to the Carpathian mountains and Dinaric Ponebšek 1917, Kohl 1977, Vrezec & Tutiš 2003). Alps, the subspecies macroura can be referred to These studies made distinction between melanis- as ‘Carpathian-Dinaric Ural Owl’. The largest part tic and non-melanistic birds but not between the of the Carpathian-Dinaric population breeds in two intermediate morphs (see below). However, high elevated montane , predominantly in these proportions were only useful for relative mixed forests but also in a few lowland comparisons between different regions because forest fragments (especially oak) in Croatia, Serbia, museum collections are not the best reference for and Slovenia (Rašajski & Vuc̆anović estimating the proportion of melanistic individu- 1998, Vrezec & Tutiš 2003, Krištin et al 2007). als. The reason for this is that the provenance of

160 Melanism and plumage variation in macroura Ural Owl

173 Ural Owl / Oeraluil Strix uralensis liturata, southern , 19 April 2008 (Al Vrezec). Pale facial disk is typical for northern subspecies of Ural Owl. 174 Ural Owl / Oeraluil Strix uralensis ‘momiyamae’ (included in S u hondoensis), , Japan, 17 April 2004 (Aki Higuchi). In eastern part of range, southern Ural Owls are darker and more brownish than northern subspecies. 175 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 6 April 2007 (Al Vrezec). Facial disk of pale morph. 176 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 11 May 2007 (Andrej Kapla). Grey morph individual with prominent circumocular barring. 177 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 6 June 2007 (Andrej Kapla). Facial disk of melanistic morph. 178 Ural Owl / Oeraluil Strix uralensis macroura, Ljubljana, Slovenia, 20 November 2004 (Al Vrezec). Facial disk of melanistic morph; very dark individual with almost blackish facial disk.

161 Melanism and plumage variation in macroura Ural Owl

1 2

Figure 2 Variability of plumage coloration in Carpathian-Dinaric Ural Owls Strix uralensis macroura with four colour morphs: 1 pale morph, 2 grey morph, 3 partially melanistic morph, and 4 melanistic morph (Žarko Vrezec)

3 4

162 Melanism and plumage variation in macroura Ural Owl

Plumage coloration in subspecies of Ural Owl Ural Owl subspecies. The wing length is 354-415 Northern Ural Owls (eg, Fennoscandian subspe- mm, much larger compared with the northern cies S u liturata) are generally very pale with subspecies (310-396 mm), Japanese subspecies strongly contrasting black streaks on flanks and (259-347 mm) or davidi (371-372 mm; König et al head. The facial disk is pale, almost white. The 1999, Scherzinger & Fang 2006). Macroura has back and wings are more greyish but still a con- slight barring in the facial disk around the , trasting black-and-white pattern is prominent. resembling S nebulosa but not so There are no records of very dark or melanistic distinct (circumocular barring is present also in individuals and even birds with a darker or black- davidi). However, this pattern is reported to be ab- ish facial disk are extremely rare in liturata (Pertti sent in c 10% of the individuals and can be found Saurola pers comm). The other northern subspe- in some individuals from the northern subspecies cies, eg, nominate uralensis, are reported to be as well (Kohl 1977). In my data set from Slovenia, even paler (Kohl 1977, Mikkola 1983). However, circumocular barring was absent in c 14% (n=22) also in northern populations some colour varia- of individuals, excluding melanistic birds, where tion is noted, described as ‘light’ and ‘dark’ this barring is not visible anyway (table 1). The morphs in König et al (1999). In liturata from general impression of macroura compared with Finland, I noted that besides very pale individuals the northern subspecies is formed by the larger with a whitish facial disk (‘pale morph’), some size, longer tail and darker plumage with less con- birds have a more greyish facial disk (‘dark trasting patterns. morph’), but in general birds are still very pale In macroura, based on my studies, four (or compared with macroura. more) colour morphs can be separated. Of these, In southern populations, Ural Owls are general­ the two extreme morphs can be easily distin- ly darker than in northern. In the eastern part of guished, the ‘pale’ and the ‘melanistic’ morph. the range, they are more brownish (König et al The latter refers to individuals with a very dark, 1999) than in the western. Birds belonging to da- almost black facial disk and dark chocolate-brown vidi in China are dark brown with blackish-brown plumage with a much subdued streaking pattern scapulars, unicoloured brownish-black central and with an almost blackish appearance in the tail-feathers and a dark facial disk (Scherzinger & field. These are the two outermost morphs ina Fang 2006). Japanese Ural Owls are paler than cline of plumage coloration. In general, at least davidi with greyish-brown feathers and a darker two other, intermediate morphs can be distin- facial disk and the pattern on the upperparts shows guished, the ‘grey’ and the ‘partially melanistic’ less contrast compared with the northern subspe- morphs. The grey morph is represented by darker cies. In the western part of the range (macroura), grey individuals in which the pattern of streaking birds are dark greyish. However, the colour pat- is still prominent. In partially melanistic individu- tern in macroura varies strongly, from very pale to als, usually the head and facial disk are dark completely dark chocolate-brown, almost black, blackish as in completely melanistic birds but the with intermediate variations (see below). rest of the body is paler, although the degree varies strongly between individuals. According to Morphological characteristics of macroura my study of museum skins and field observations, Individuals of macroura are the largest among general estimations indicate that partially melan-

Table 1 Proportion of four colour morphs in the popula- Table 2 Proportion of melanistic, including partially tion of Carpathian-Dinaric Ural Owl Strix uralensis ma­ melanistic, individuals in museum collections across croura in Slovenia, and frequency of presence of circum­ distribution range of Carpathian-Dinaric Ural Owl Strix ocular barring in each morph uralensis macroura (after published sources: Kohl 1977, Vrezec & Tutiš 2003) colour morph % in population frequency of circumocular region % of melanistic number of barring individuals inspected birds pale 23.1% 57.1% grey 64.1% 100.0% North Carpathians 40.0% (n=10) 25 partially melanistic 2.6% 0.0% 6.7% (n=4) 60 melanistic 10.3% 0.0% Romania 2.6% (n=5) 194 n 39 26 former Yugoslavia 21.0% (n=20) 95 Slovenia and Croatia 14.9% (n=22) 148

163 Melanism and plumage variation in macroura Ural Owl

179 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 6 April 2007 (Andrej Kapla). Wing of pale morph. 180 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 11 May 2007 (Andrej Kapla). Wing of grey morph.

164 Melanism and plumage variation in macroura Ural Owl

181 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 6 June 2007 (Andrej Kapla). Wing of melanistic morph. 182 Ural Owl / Oeraluil Strix uralensis macroura, Ljubljana, Slovenia, 20 November 2004 (Al Vrezec). Wing of melanistic morph. Very dark individual.

165 Melanism and plumage variation in macroura Ural Owl

183 Variability of barring pattern on central tail-feathers in Ural Owls Strix uralensis macroura (Al Vrezec). Note that on the right feather from dark melanistic morph individual barring pattern is greatly reduced due to increase of melanin. istic birds are the rarest and individuals of the pale to dark is clinal, the number of distinguishable morph and grey morph are the most common morphs is difficult to define and the four morphs (table 1). Because the plumage variation from pale proposed here and their demarcation must be considered somewhat arbitrary. The first identification step to attribute an indi- Figure 3 First published illustration of melanistic morph of Carpathian-Dinaric Ural Owl Strix uralensis macroura vidual bird to one of the four morphs is the deter- given by Hacquet (1791) and described as ‘Strix nigra’ mination of the colour of the facial disk, which can be separated into three groups: 1 whitish (pale with very little dark marks resembling pale north- ern subspecies, eg, liturata; occurs in pale morph); 2 greyish (grey facial disk, which is in some birds very prominent since on photographs the colour of feathers on belly and flanks can be very varia- ble due to the light conditions during photograph- ing and are therefore an unreliable indication for identification; occurs in grey morph); and 3 dark (dark brown or blackish facial disk; occurs in par- tially melanistic morph and melanistic morph). The second identification step is to separate par- tially melanistic from melanistic birds, for which the colour of body plumage is important (the col- our pattern of wings was not considered since also in melanistic birds wings still have bright spots): 1 the whole body is dark brown with less prominent black streaks (melanistic morph), and 2 some parts of the body, especially distal parts from the head, are brighter with prominent black streaking (partially melanistic morph). Between different morphs, the colour of the bright yellow bill is not variable, although its ap- pearance is clearly more noticeable in dark indi- viduals because of the stronger contrast with the surrounding dark feathers. The characteristic feather wreath around the facial disk is distinct in

166 Melanism and plumage variation in macroura Ural Owl

184 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 14 December 2007 (Miha Krofel). Pale morph individual. 185 Ural Owl / Oeraluil Strix uralensis macroura, near Krakow, Poland, 2 May 2008 (Chris van Rijswijk/ birdshooting.nl). Partially melanistic morph individual. Appearance of partially melanistic or melanistic morph birds is almost blackish in the field. 186 Ural Owl / Oeraluil Strix uralensis macroura, near Krakow, Poland, 2 May 2008 (Chris van Rijswijk/birdshooting.nl). Grey morph individual.

167 Melanism and plumage variation in macroura Ural Owl

187 Ural Owl / Oeraluil Strix uralensis macroura, central 188 Ural Owl / Oeraluil Strix uralensis macroura, central Slovenia, 21 May 2008 (Al Vrezec). Fledgling of par- Slovenia, 21 May 2008 (Al Vrezec). Fledgling of pale or tially melanistic or melanistic morph, with no visible grey morph, with well distinguishable barring pattern on bars on back or belly and with dark facial disk. back and belly. individuals of the pale and grey morphs, much morph Ural Owls were found to occur over the less so in partially melanistic birds and almost im- whole Carpathian-Dinaric distribution range but perceptible in melanistic individuals. The circum­ according to museum collections, dark individu- ocular barring is present only in pale and grey als are more common in the southern part (Kohl morph individuals but not in melanistic birds. 1977; table 2). From the field, only data from the I have found that circumocular barring is present recent intensive studies of breeding pairs in the in all grey morph owls but is absent in c 43% of Dinaric Alps in Croatia and Slovenia are available, pale morph individuals (table 1). The increase of revealing that the proportion of partially mela­ pigments (melanin) is shown also in the barring nistic morph and melanistic morph individuals pattern of the primaries and secondaries, with the (taken together) is c 6% in the wild (n=54; Vrezec dark bars generally being larger in melanistic indi- & Tutiš 2003). Considering additional data from viduals than in pale or grey birds. Also in the tail- Slovenia collected for this study, my conclusion is feathers, especially the pair of central feathers, that the proportion of partially melanistic and only a few pale patches with no clear barring pat- melanistic individuals is 5-15% in the wild, but tern are present in melanistic individuals. Similar can vary locally. almost unicoloured central tail-feathers are also It seems that Ural Owls are becoming darker found in davidi (Scherzinger & Fang 2006). towards the south, ie, towards warmer and more The different colour morphs are distinguishable humid areas, as would be expected when consid- already in downy fledglings, especially between ering ‘Gloger’s rule’ (eg, Newton 2003). Melanism paler (pale, grey) and darker (partially melanistic, was so far confirmed only in macroura and not in melanistic) morphs. Melanistic young have dark other subspecies, so a mechanism of inheritance blackish down with no visible bars on the back or is in question. No in-depth genetic as well as mor- on the belly and have a darker facial disk. phological and ecological studies on melanism in macroura have been conducted yet but certain Melanism in macroura conclusions can be put forward on the basis of The first mention and published figure of a melan- current knowledge. Since melanistic owls are istic morph Ural Owl dates back to the 18th cen- blackish or dark brown, the increase of eumelanin tury when Hacquet (1791) described owls found is expected in a form of eumelanism (cf van in the Carpathian mountains as ‘Strix nigra’ (figure Grouw 2006). Colour morphs are frequently ge- 3). He correctly identified these dark owls as Ural netically controlled by simple Mendelian genes Owls, referring to the studies of Giovanni Antonio and can serve as genetic markers in population (Ioannis Antonii) Scopoli from Slovenia, who de- studies (Gill 1995). However, melanism is not scribed these birds as ‘Strix sylvestris’ (Scopoli necessarily caused by gene mutation. Also envi- 1769, Vrezec et al in press). Later, melanistic ronmental factors such as malnutrition, disease or

168 Melanism and plumage variation in macroura Ural Owl low exposure to sunlight can cause concentration Samenvatting of pigments (van Grouw 2006). In Ural Owl, it is Melanisme en kleedvariatie bij ondersoort macroura van not clear if melanism is genetically or environ- Oeraluil Oeraluil Strix uralensis is een overwegend bo- mentally determined but some observations are reale broedvogel in Eurazië met tenminste drie zuidelij- instructive. First, dark melanistic chicks occur in ke broedpopulaties die als glaciale relictpopulaties kun- nen worden beschouwd: in Japan (tenminste drie onder- mixed broods with pale chicks. Second, the plum- soorten), China (S u davidi, tegenwoordig vaak als age coloration is extremely variable in macroura, aparte soort beschouwd), en in Centraal- en Zuidoost- with all intermediate stages occurring, but paler Europa (S u macroura). De kern van de verspreiding van owls are much more common than dark ones. macroura ligt in de Karpaten en Dinarische Alpen Third, in the reintroduction programme in the (Dinaridi). Macroura is de grootste van alle ondersoor- Bohemian Forest, Germany, a stock of mixed sub- ten van Oeraluil met een langere staart en een donker- species was used with birds originating from litu- der verenkleed met meer contrastrijke tekening. rata and macroura but nevertheless after some Macroura is de enige ondersoort waarbinnen met regel- generations also dark melanistic owls occurred in maat melanistische exemplaren voorkomen. Vier (of meer) kleurvormen kunnen worden onderscheiden, these broods (Scherzinger 2006). These examples waarvan twee (‘licht’ en ‘melanistisch’) gemakkelijk te suggest that melanism in Ural Owls is most prob- onderscheiden zijn. Melanistische exemplaren zijn erg ably genetically determined as a recessive charac- donker met een bijna zwart masker en donker chocola- ter. Even in mixed broods between liturata and debruin verenkleed met een nauwelijks zichtbaar pa- macroura, the recessive genes can express them- troon van streping en lijken in het veld bijna egaal zwart. selves after some generations. However, it is not Er is een reeks van kleurvariaties en tenminste twee ‘tus- clear how the cline of variation is determined in sengroepen’ kunnen als aparte kleurvormen worden be- macroura and if colour morphs are really control- noemd, ‘grijze’ en ‘partieel melanistische’ exemplaren. led by simple Mendelian genes, as suggested De vier kleurvormen zijn weergegeven in figuur 2. Deze kleurvormen zijn zowel bij adulte vogels als bij above. However, it was shown in some birds that (nest)jongen te onderscheiden. Hoewel melanistische eumelanism is a response to environmental hetero­ en partieel melanistische exemplaren gevonden zijn geneity which generates diversifying selection, binnen het gehele Karpatisch-Dinarische verspreidings- where differently coloured individuals are adapt- gebied toonde onderzoek aan museumbalgen aan dat ed to different environmental conditions (Roulin donkere exemplaren vaker voorkomen in het zuidelijke et al 2008). deel van het verspreidingsgebied (tabel 2). Veldonderzoek The phenomenon of regularly occurring mela­ bij populaties in de Dinarische Alpen in Kroatië en nism in the populations of macroura is still very Slovenië gaf aan dat het aandeel donkere vogels (mela- poorly researched and this paper mostly presents nistisch en partieel melanistisch) hier 5-15% bedraagt (tabel 1). Melanisme bij Oeraluilen is nog niet diep- an overview of current knowledge. Future studies gaand onderzocht maar waarschijnlijk betreft het een should therefore focus on more detailed morpho- recessief genetisch kenmerk. logical characteristics of the colour variation in macroura, determine the mechanisms of inherit- References ance and search for a possible ecological function Feldner, J, Rass, P, Petutsching, W, Wagner, S, Malle, G, of this melanism considering breeding success Buschenreiter, R K, Wiedner, P & Probst, R 2006. and survival rate of melanistic individuals. Avifauna Kärntens – Die Brutvögel. Klagenfurt. Genero, F & Benussi, E 2007. New data and status of Acknowledgements Ural Owl (Strix uralensis) in Italy. In: Müller, J, Scherzinger, W & Moning, C (editors), European Ural For discussion and information on liturata Ural Owl workshop, Nationalpark Bayerischer Wald, Owls, I am grateful to Pertti Saurola. Davorin Grafenau, pp 36-41. Tome gave me some valuable comments on the Gill, F B 1995. Ornithology. New York. first draft of the manuscript. I would like to thank Grouw, H van 2006. Not every white bird is an albino: to Aki Higuchi, Andrej Kapla and Miha Krofel for sense and nonsense about colour aberrations in birds. supplying photographs and to Žarko Vrezec for Dutch Birding 28: 79-89. adding drawings to the paper. For the help in mu- Hacquet, B 1791. Neueste physikalisch-politische seum skin study, I thank Janez Gregori, curator of Reisen in den Jahren 1788-95 durch die Dacischen the Slovenian Museum of Natural History in und Sarmatischen oder Nördlichen Karpathen 2. Nürnberg. Ljubljana. For help in search of photographic ma- del Hoyo, J, Elliott A & Sargatal, J (editors) 1999. terial and valuable discussion over its analysis Handbook of the birds of the world 5. Barcelona. I want to thank to Tomaž Mihelic̆. Damijan Denac Kohl, S 1977. Über die taxonomische Stellung der helped me to prepare the map. Südost-europäischen Habichtskäuze, Strix uralensis macroura , 1810. Muzeul Brukenthal, Studii si

169 Melanism and plumage variation in macroura Ural Owl

Comunicäri – St nat 21: 309-334. Rašajaski, J & Vuc̆anovic̆, M 1998. Uralska sova (Strix König, C, Weick, F & Becking, J-H 1999. Owls: a guide uralensis macroura, Wolf, 1810), nova gnezdarica to the owls of the world. Mountfield. Vojvodine. Ciconia 7: 112-115. Krištin, A, Mihok, J, Danko, Š, Karaska, D, Pac̆enovsky, Reiser, O 1939. Materialien zu einer Ornis Balcanica, I S, Saniga, M, Bodova, M, Balazs, C, Šotnar, K, Kornan, Bosnien und Herzegowina nebst Teilen von Serbien J & Olekšak, M 2007. Distribution, abundance and und Dalmatien. Wien. conservation of the Ural Owl Strix uralensis in Roulin, A, Gasparini, J, Bize, P, Ritschard, M & Richner, Slovakia. In: Müller, J, Scherzinger, W & Moning, C H 2008. Melanin-based colorations signal strategies (editors), European Ural Owl workshop, Nationalpark to cope with poor and rich environments. Behav Ecol Bayerischer Wald, Grafenau, pp 8-15. Sociobiol 62: 507-519. Lukac̆, G 2007. Ural Owls (Strix uralensis) in Croatia – Scopoli, I A 1769. Annus I. Historico-Naturalis. their status and conservation. in Europe. In: Müller, J, Descriptiones Avium. Lipsiae. Scherzinger, W & Moning, C (editors), European Ural Scherzinger, W 2006. Die Wiederbegründung des Owl workshop, Nationalpark Bayerischer Wald, Habichtskauz-Vorkommens Strix uralensis im Grafenau, pp 32-35. Böhmerwald. Ornithol Anz 45: 97-156. Mebs, T 2007. Summary on population and conserva- Scherzinger, W & Fang, Y 2006. Field observations of the tion status of the Ural Owl (Strix uralensis) in Europe. Sichuan Wood Owl Strix uralensis davidi in western In: Müller, J, Scherzinger, W & Moning, C (editors), China. Acrocephalus 27: 3-12. European Ural Owl workshop, Nationalpark Tomiałojć, L & Stawarczyk, T 2003. The avifauna of Bayerischer Wald, Grafenau, pp 6-7. Poland. Wrocław. Mikkola, H 1983. Owls of Europe. London. Vrezec, A 2007. The Ural Owl (Strix uralensis macroura) Newton, I 2003. The speciation and biogeography of – Status and overview of studies in Slovenia. in birds. London. Europe. In: Müller, J, Scherzinger, W & Moning, C Novc̆ić, I 2004. List of Strigiformes species in the (editors), European Ural Owl workshop, Nationalpark Belgrade Natural History Museum bird collection. Bayerischer Wald, Grafenau, pp 16-31. Arch Biol Sci 56: 79-88. Vrezec, A, Smole, J & Vrh Vrezec, P in press. Descriptions Obratil, S 1977. Pregled istraživanja ornitofaune Bosne i of European owl species by Scopoli (1769): a prob- Hercegovine. Sarajevo. lem of overlooked European owl names? Ardea. Pietiäinen, H & Saurola, P 1997. Ural Owl Strix uralen- Vrezec, A & Tutiš, V 2003. Characteristics of Northern sis. In: Hagemeijer, E J M & Blair, M J (editors), The Dinaric Ural Owl (Strix uralensis macroura) popula- EBCC atlas of European breeding birds: their distribu- tion. In: Schwerdtfeger, O & Schwerdtfeger, J (editors), tion and abundance, London, pp 412-413. Ecology and conservation of European owls, 4th Ponebšek, J 1917. Naše ujede, I del: Sove. Ljubljana. Meeting of European Owl-Experts, Dornbirn, p 75.

Al Vrezec, National Institute of Biology, Vec̆na pot 111, SI-1000 Ljubljana, Slovenia ([email protected])

170

View publication stats