Translator Disclaimer
1 December 2009 Synthesis of 312 Studies on the Diet of the Long-Eared Owl Asio otus
Author Affiliations +
Abstract

In this literature review, I examined 475 publications with information on the global diet of the Long-eared Owl Asio otus. Data within 312 publications were entered into a database, and quantitative diet data were available from 194 of these publications. The composite data set identified 477 different prey: 180 mammal, 191 bird, 15 reptile, 7 amphibian, and 1 fish species, and 83 invertebrate groupings. In 798 prey lists reflecting 813 033 prey items, small mammals accounted for 93.3% and birds for 6.4% of the vertebrate prey. Prey ranged from 1–500 g, with the vast majority of prey consisting of species ≤50 g. Twenty-three species predominate the prey in at least one species list. Diet composition at the family level was similar in different regions, but considerable differences were shown at the species level.

INTRODUCTION

The Long-eared Owl Asio otus is distributed over wide areas of North America, Europe, Middle East and Asia, and is relatively common (Mebs & Scherzinger 2000). While a large number of publications reporting on the owls' diet from pellet analyses exist, a quantitative synthesis is missing. Many diet papers are either of an older date, restricted to subregions of the species' range, or do not provide quantitative information (Uttendörfer 1939, Uttendörfer 1952, Smeenk 1972, Schmidt 1975, Marti 1976, Marks et al. 1994). For owls, brood sizes and fledging rates (which are crucial measurements in population biology) depend on food availability. Consequently, understanding of diet and the dynamics of prey species become key elements in conservation efforts. The aim of this paper is to compile a synthesis of the global diet of the Long-eared Owl, to aid in understanding this species' ecology.

METHODS

Various bibliographies and databases were searched for Long-eared Owl diet papers (e.g. Clark et al. 1978, Muller 1996, Mammen et al. 1997, Muller 2000;  www.nisc.com, Ornithological Worldwide Literature OWL  http://egizoosrv.zoo.ox.ac.uk/OWL). Entries into the library of the Swiss Ornithological Institute Sempach were also checked. Data on Long-eared Owl prey was entered into a database. Country, place, longitude and latitude, date, type of prey, proportions of biomass and absolute number of prey items were recorded. If necessary, absolute numbers of prey items were calculated from published percentages. Cases in which this conversion was not possible were excluded from the analysis, e.g. if only proportions of biomass were given. Obvious misprints were corrected before being entered into the database. When a publication contained several sub-lists, i.e. several places, years or seasons, each list was entered separately.

For analyses on the overall prey spectrum in the diet, all sources were included. If all sub-lists together constituted more than 75% of the items in the total list, the sub-lists were used. For qualitative analyses only complete lists including at least 100 prey items were used. I excluded lists in which the following situations occurred: (1) the number of unclassified vertebrate prey items exceeded 10%; (2) ‘unclassified voles’ made up more than 20% of all classified items; or (3) ‘unclassified Microtus’ made up more than 20% of all Microtus individuals.

Body mass of the prey species were derived from the literature. For species below 100 g, the mean adult body mass was used. For larger species, the minimal adult body mass was used because Long-eared Owls are known to prefer smaller prey items. For all invertebrates, a body mass of 1 g was assumed. Percentages refer to the sum of all vertebrate taxa unless stated otherwise. Invertebrates are given as proportion per 100 vertebrates. Apodemus sylvaticus and A. flavicollis were considered as one prey type as well as species of the genus Mus, Peromyscus, Reithrodontomys and bats, birds, reptiles, amphibians and invertebrates, since they were usually not differentiated in the publications.

Each list was assigned to one or more of eight major geographical regions: North America, northern Europe (Scandinavia including Denmark, the Baltic States and northern Russia), the British Isles (including Ireland), Central Europe (Germany, Poland, Czech Republic, Slovakia, Austria, northern Switzerland, northern France, Benelux), southern Europe (Spain, Mediterranean France, Italy, Southern Switzerland), southeastern Europe (Slovenia, Hungary, Ukraine and countries south of it), Africa including the Middle East (North Africa, Middle East and Canary Islands), and Asia (excluding Middle East).

RESULTS

In this study, 475 publications with information on prey of Long-eared Owls were examined. Because of logistical constraints, I did not have access to, or necessary language translation support for another 198 references. A total of 312 publications with information on diet were included in the database. Quantitative data could be extracted from 194 publications with a total of 798 prey lists reflecting 813 033 prey items (Table 1; Appendix 1). The majority of prey information, 527 lists reflecting 509 955 prey items, came from Central Europe.

Prey spectrum

Worldwide, a total of 477 prey species of the Longeared Owl were found (Table 2). Prey reflected 180 mammal, 191 bird, 15 reptile, 7 amphibian, and one fish species. Many invertebrate prey remains could not be classified to the species level, rather they were assigned to 83 different invertebrate groupings. The vast majority (99.6%) of identified prey items were vertebrates (Table 1). Among the vertebrates, mammals made up the majority of the prey, on average 93.5%. Birds were the second largest group with 6.2% (Table 3). The remaining vertebrate classes summed to a fraction of a percentage. In southern Europe 1.8 invertebrates could be found per 100 vertebrates. By contrast, in African prey lists, there were 26.9 invertebrates per 100 vertebrates. When related to the body mass of the prey species, however, invertebrates accounted for only 1% of the biomass.

The broadest prey spectrum (195 species) was found in Central Europe (Table 2). Prey spectrums from the other regions were: southern Europe (168 species), North America (133 species), south-eastern Europe (102 species), the British Isles (74 species), northern Europe (59 species), Africa/Near East (59 species) and Asia (45 species). However, only a few studies were available from these latter two regions.

Body mass of adult prey items ranged from less than 1 g (invertebrates) to over 500 g, with the majority of prey consisting of species ≤ 50 g (Fig. 1). When preying on heavier species, mostly juveniles were taken. The heaviest verified prey seized by a Long-eared Owl were two Ruffed Grouse Bonasia umbellus (Sutton 1926); female grouse average 575 g (Rusch et al. 2000) in their first winter, while males and older females are heavier.

Table 1.

Number of prey lists and prey items of the Long-eared Owl grouped by regions.

t01_615.gif

Figure 1.

The global avian and mammal prey species of the Long-eared Owl, arranged by adult mass of the prey species. Black portion of bars reflect avian species, grey portions of bars, mammal species.

f01_615.eps

Table 2.

Number of prey species of Long-eared Owl grouped by systematic class and region.

t02_615.gif

Table 3.

Number of prey items of Long-eared Owl grouped by class and region.

t03_615.gif

Diet composition in major regions

Frequency of Prey. Overall, regional differences in the frequencies of vertebrate prey were small (Table 3). The percentages of mammals in the diet for the various regions were: North America (98.1%), northern Europe (96.6%), Central Europe (94.2%), south-eastern Europe (93.0%), southern Europe (89.0%), the British Isles (87.9%), Africa/Middle East (86.4%), and Asia (80.9%). The percentages of birds in the diet for the regions were: North America (1.8%), northern Europe (3.4%), Central Europe (5.8%), south-eastern Europe (11.0%), southern Europe (5.9%), the British Isles (12.0%), Africa/Middle East (6.8%), and Asia (19.1%). The African prey lists contained a relatively large number of reptiles (6.8%) (Table 3).

The largest prey class among the mammals were rodents which made up 91.7% of the vertebrates (lowest 79.5% in Asia, highest 93.3% in northern Europe). The next common mammalian group were insectivores, reflecting 1.2% of the vertebrates. The insectivores were relatively scarce in prey lists from Africa/Middle East, Asia, and Central Europe (<0.7%), but slightly more frequent in North America (4.1%), northern Europe (3.2%) and the British Isles (3.5%).

At the taxonomic level of family, the pattern in the prey lists is less uniform. In Central Europe, Arvicolinae dominate with 80.1% of the vertebrate prey. In the rest of Europe, in North America and Asia, this family was also predominate, although the proportions were markedly lower (minimum 43.1%). The Murinae were second in Europe and the dominant family in Africa/Middle East (71.5%) and Asia (59.8%) while they are nearly absent in North America. In North America, the Cricetinae were the second largest family (51.0%).

Even more pronounced differences were apparent at the genus level. The genus Microtus was the most frequent prey in five regions: M. arvalis was the most common species in Central Europe and in south-eastern Europe (72.5%, 46.7%, respectively); M. agrestis in northern Europe and British Islands (48.8% and 37.0%, respectively); and M. pennsylvanicus in North America (23.8%). In south-eastern Europe, Apodemus was the most numerous genus accounting for 21.0% of the prey frequency, while in the British Islands, northern Europe, and south-eastern Europe the same species accounted for 35.6, 24.7 and 22.1%, respectively. In Africa, 67.3% of the diet was comprised of the species Mus.

Table 4.

Maximum proportion of prey species in Long-eared Owl diet. Prey species which reached at least 50% by frequency in at least one list were included. The number of lists in which a certain prey species is dominant is given between parentheses.

t04_615.gif

Worldwide, there are at least 23 species which appear as the most frequent prey in at least one list (Table 4). In Central Europe Micotus arvalis is the most common prey species in 81.6% prey lists. In other Central European lists, Apodemus sp. (8.5%), birds (7.2%), Arvicola terrestris, Microtus agrestis, M. oeconomus and Clethrionomys glareolus predominate.

Biomass of Prey. The 394 vertebrate and 83 invertebrate groups were organized by categories, based on the mass of the adult for each species/group. Weight categories for bird and mammal species are shown in Fig. 1, as these were the major prey. The majority (66.5%) of the vertebrate species were <50 g. Overall, the percentages by biomass correspond largely to the percentages of prey items. Even at the level of prey types, the differences between percentages of prey items and biomass are usually small. In half the cases, this difference is below 3.5% and in 90% of cases it is less than 11.1% (Fig. 2). The only exception to this pattern is found in prey lists in which the genus Rattus is frequent. The largest differences between the percentages of biomass and prey items at the class level occur in Asia. Mammalia account for 73.1% of the biomass but make up 80.9% of the prey items; birds account for 26.5% of biomass and 19.1% of prey items.

Figure 2.

Percentages of prey items compared to percentages of prey biomass. Triangles = Rattus spec. n = 6072 prey items from 798 prey lists of the Long-eared Owl.

f02_615.eps

DISCUSSION

Representation of diet studies

Compared to the estimated global distribution of Long-eared Owls, diet studies are strongly reported in some areas, and under-represented in others. Data from Central Europe (especially Germany) is most strongly represented. There are only relatively few lists with quantitative data from North America. Diet lists from Africa and Asia are limited and likely under-represent actual prey arrays (however, lists from Asian areas exist but were logistically difficult to obtain, and language translation was not available to this researcher). Diet lists within a certain region are not necessarily representative either, with some papers reporting dietary exceptions, e.g. data from severe winters or special habitats such as islands.

Proportions and biomass

In this study, I refer to proportions of prey items because uncertainties are involved in the calculation of body mass proportions. In many prey species, body mass varies considerably with geographical location, sex and individual traits. Often body mass of the lightest adults is only half of that of the heaviest. Also, it has been shown that Long-eared Owls prefer smaller items of the larger prey species. Further publications containing data on sex, age classes and a species mean (and range) of mass for prey would be very helpful for biomass calculations (Tome 2000, Pirovano et al. 2000).

The composition of the Long-eared Owls' diet depends on an array of interacting factors (Fig. 3). Season and geographical location of the diet samples, which are usually indicated in the publications, both have an effect on prey diversity. Some papers mention various other factors. Usually, the most abundant species available are preyed upon most often (Canova 1989, Guidoni et al. 1999). The proportion of Microtus in the prey lists increases with increasing density of this species (Schmidt 1971, Veiga 1981, Wijnandts 1984, Korpimäki 1992, Tome 1994, 2003).

Aspects of predation

Prey abundance does not necessarily explain the degree of predation, as prey need to be accessible to the owls. Factors like vegetation, weather and prey behaviour can influence accessibility (Fig. 3). The Long-eared Owl prefers low and sparse vegetation for hunting (Nilsson 1981, Aschwanden et al. 2005). Therefore, prey lists from habitats with different vegetation structure and from different cultivation stages (e.g. before or after harvest of cereal grains) can vary considerably (Tinbergen 1932). Apodemus, for instance, is captured more frequently in or near woods (Wijnandts 1984).

Accessibility is influenced indirectly by the season (Fig. 3). Some authors reported no seasonality (Graber 1962, Marti 1974, Armstrong 1958 in Marti 1976) while others found differences between winter and summer (Degn 1976, Nilsson 1981, Wijnandts 1984, San Segundo 1988, Bertolino et al. 2001, Rubolini et al. 2003).

Weather has an influence on the accessibility of prey items. Many prey species profit from snow cover and this is mirrored in the diet lists (Elvers et al. 1979, Wijnandts 1984, Schmitz 1987, Ancelet 1987, Canova 1989). Hunting sites and hence prey composition differ in nights with and without wind (van Manen 2001). In America, however, wind did not influence hunting site selection in radio-tracked breeding Long-eared Owls (Craig et al. 1988).

The behaviour of a prey species can influence its availability for an owl. Young males of otherwise subterranean rodents display a dispersal pattern during which they can be found on the surface and are therefore more vulnerable to predation by owls. This is a possible reason for the preference of young Arvicola terrestre (Saucy 1988, Tome 2000) and Thomomys talpoides (Bull et al. 1989). Behaviour may also explain the vast differences in the genera Microtus and Pitymys in the prey lists of Long-eared Owls in Europe. While Microtus can be seen regularly on the surface, most Pitymys species, e.g. P. multiplex, live much more subterraneously (Hausser 1995).

Figure 3.

Possible factors influencing diet composition of the Long-eared Owl.

f03_615.eps

Not all species are equally attractive prey for Long-eared Owls. The attractiveness of a prey species depends on species-specific and individual qualities. Most important is probably size. Generally, vertebrates ≤ 300 g are potential prey items for Long-eared Owls (Fig. 1), with the dominate prey consisting of species ≤ 50 g. The larger prey items reported were probably weakened or injured at the time they were seized. It was assumed several times that owls fed on carcasses. Of the larger species, the smaller individuals are often preferred, e.g. in Arvicola terrestris (Saucy 1988, Tome 2000), Rattus norvegicus (Gawlik & Banz 1982, Hillis et al. 1988, Ekins & Steward 1994, Pirovano et al. 2000) and Thomomys talpoides (Janes & Barss 1985, Bull et al. 1989, Marks et al. 1994). In medium-sized prey species, i.e. Clethrionomys and Apodemus, immature individuals also tend to be taken more often (Lodé 1994). Tome (2000) found a significant size difference between individuals captured as prey by owls and those from trapping efforts in all prey species except for Apodemus sylvestris.

Shrews are avoided by Long-eared Owls (Gross 1943) and items caught are sometimes even dropped (Thiollay 1968) presumably because of their smell (or taste). Correspondingly, compared to the prey lists of other owls, especially the Barn Owl, collected in the same place at the same time, there were fewer shrews found as Long-eared Owl prey (Uttendörfer 1939, Lopez-Gordo et al. 1977, Veiga 1980, Erfurt & Stubbe 1987, Roulin 1996). Individuals with poor body condition could also be easier prey for Long-eared Owls. In the pellets, prey items with deformed bones are regularly found and their proportion decreases over the winter (Manegold 2000). Yet, it is not known whether such items are preyed upon selectively. In a lab experiment, a Long-eared Owl hunted more lab mice which were infected with Sarcocystis dispersa (Vorisek et al. 1998).

ACKNOWLEDGEMENTS

I am very grateful to Raymond Lévêque, Christian Marti and Niklaus Zbinden for their assistance in searching the literature, Dominik Thiel for the translation of the Russian papers and Judith Fischer for the translation of this article. Judith Fischer, Lukas Jenni, Luc Schifferli, and David H. Johnson helped improve the manuscript.

REFERENCES

1.

H. Alivizatos & V. Goutner 1999. Winter diet of the Barn Owl (Tyto alba) and Long-eared Owl (Asio otus) in northeastern Greece: a comparison. J. Raptor Res. 33: 160–163. Google Scholar

2.

C. Ancelet 1987. Variation hivernale des proies chez le Hibou moyen-duc (Asio otus). Héron 20: 81–88. Google Scholar

3.

J. Aschwanden , S. Birrer & L. Jenni 2005. Are ecological compensation areas attractive hunting places for Kestrels Falco tinnunculus and Long-eared Owls Asio otus J. Ornithol. 146: 279–286. Google Scholar

4.

S. Bertolino , E. Ghiberti & A. Perrone 2001. Feeding ecology of the Long-eared Owl (Asio otus) in northern Italy: is it a dietary specialist? Can. J. Zool. 79: 2192–2198. Google Scholar

5.

E.L. Bull , A.L. Wright & M.G. Henjum 1989. Nesting and diet of Long-eared Owls in conifer forests, Oregon. Condor 91: 908–912. Google Scholar

6.

L. Canova 1989. Influence of snow cover on prey selection by Long-eared Owls Asio otus. Ethol. Ecol. Evol. 1: 367–372. Google Scholar

7.

R.J. Clark , D.G. Smith & L.H. Kelso 1978. Working bibliography of owls of the world. Washington DC. Google Scholar

8.

E.H. Craig , T.H. Craig & L.R. Powers 1988. Activity patterns and home-range use of nesting Long-eared Owls. Wilson Bull. 100: 204–213. Google Scholar

9.

H.J. Degn 1976. An analysis of pellets from the Long-eared Owl in Funen. Flora Fauna 82: 59–64. (In Danish). Google Scholar

10.

G. Ekins & L. Steward 1994. Analysis of the food of Long-eared Owls roosting at Langdon Nature Reserve (TQ662875), winter 1992/93. Essex Bird Report 1993: 149–155. Google Scholar

11.

H. Elvers , P. Miech & C. Pohl 1979. Vorkommen und Ernährung der Waldohreule (Asio otus L.) im Winter 1978/79 in Berlin (West). Ornithol. Bericht Berlin (West) 4: 219–234. Google Scholar

12.

J. Erfurt & M. Stubbe 1987. Gewöllanalysen zur Untersuchung der Ernährungsbiologie von Eulen: 429–451. In: M. Stubbe (ed.) Populationsökologie von Greifvogel- und Eulenarten 1. Halle. Google Scholar

13.

H.M. Gawlik & K. Banz 1982. Zur Nahrungsökologie der Waldohreule (Asio otus L.) innerhalb des Berliner Stadtgebietes. Beitr. Vogelkde 28: 275–288. Google Scholar

14.

R.R. Graber 1962. Food and oxygen consumption in three species of owls (Strigidae). Condor 64: 473–487. Google Scholar

15.

W. Gross 1943. Beitrag zur Kenntnis der Gangweise und Ernährung der Waldohreule. Ornithol. Beob. 40: 50–53. Google Scholar

16.

R. Guidoni , D. Capizzi , L. Caroli & L. Luiselli 1999. Feeding habits of sympatric owls in an agricultural and forested landscape of central Italy. Folia Zool. 48: 199–202. Google Scholar

17.

J. Hausser 1995. Säugetiere der Schweiz. Verbreitung, Biologie, Ökologie. Birkhäuser, Basel. Google Scholar

18.

P. Hillis , J.S. Fairley , C.M. Smal & P. Archer 1988. The diet of the Long-eared Owl in Ireland. Irish Bird 3: 581–588. Google Scholar

19.

S.W. Janes & J.M. Barss 1985. Predation by three owl species on Northern Pocket Gophers of different body mass. Oecologia 67: 76–81. Google Scholar

20.

E. Korpimäki 1992. Diet composition, prey choice, and breeding success of Long-eared Owls: effects of multiannual fluctuations in food abundance. Can. J. Zool. 70: 2373–2381. Google Scholar

21.

T. Lodé 1994. Variations saisonnières de l'alimentation du Hibou moyen-duc (Asio otus) en relation avec l'évolution des densités de petit rongeurs. Alauda 62: 91–100. Google Scholar

22.

J.L. López-Gordo , E. Lázaro & A. Fernández-Jorge 1977. Comparación de las dietas de Strix aluco, Asio otus y Tyto alba en un mismo biotopo de la provincia de Madrid. Ardeola 23: 189–221. Google Scholar

23.

U. Mammen , K. Gedeon , D. Lämmel & M. Stubbe 1997. Bibliographie deutschsprachiger Literatur über Greifvögel und Eulen von 1945 bis 1995. Jahresber. Monitoring Greifvögel Eulen Europas 2. Ergebnisband: 1–190. Google Scholar

24.

A. Manegold 2000. Pathologisch veränderte Schädel der Feldmaus (Microtus arvalis) aus Eulengewöllen und die Abnahme ihres Anteils im Verlauf des Winters. Populationsökologie Greifvogel- und Eulenarten 4: 531–537. Google Scholar

25.

J.S. Marks , D.L. Evans & D.W. Holt 1994. Long-eared Owl (Asio otus). In: A. Poole & F. Gill (eds) The Birds of North America, no. 133. Academy of Natural Sciences, Philadelphia, and AOU, Washington, D.C. Google Scholar

26.

C.D. Marti 1974. Feeding ecology of four sympatric owls. Condor 76: 45–61. Google Scholar

27.

C.D. Marti 1976. A review of prey selection by the Long-eared Owl. Condor 78: 331–336. Google Scholar

28.

T. Mebs & W. Scherzinger 2000. Die Eulen Europas. Kosmos, Stuttgart. Google Scholar

29.

Y. Muller 1996. Bibliographie d'Ornithologie Française. Service du Patrimoine Naturel et Société d'Études Ornithologiques de France, Paris. Google Scholar

30.

Y. Muller 2000. Bibliographie d'ornithologie Alsacienne. Ciconia 24. Google Scholar

31.

I.N. Nilsson 1981. Seasonal changes in food of the Long-eared Owl in southern Sweden. Ornis Scand. 12: 216–223. Google Scholar

32.

A. Pirovano , D. Rubolini , S. Brambilla & N. Ferrari 2000. Winter diet of urban roosting Long-eared Owls Asio otus in northern Italy: the importance of the Brown Rat Rattus norvegica. Bird Study 47: 242–244. Google Scholar

33.

A. Roulin 1996. Alimentation hivernale de la Chouette effraie (Tyto alba), du Hibou moyen-duc (Asio otus), du Busard Saint-Martin (Circus cyaneus) et du Faucon crécerelle (Falco tinnunculus). Bull. Soc. Vaudois Sci. Nat. 84: 19–32. Google Scholar

34.

D. Rubolini , A. Pirovano & S. Borghi 2003. Influence of seasonality, temperature and rainfall on the winter diet of the Long-eared Owl, Asio otus. Folia Zool. 52: 67–76. Google Scholar

35.

D.H. Rusch , S. DeStefano , M.C. Reynolds & D. Lauten 2000. Ruffed Grouse (Bonasa umbellus). In: A. Poole & F. Gill (eds) The Birds of North America. Academy of Natural Sciences Philadelphia, and AOU, Washington, D.C. Google Scholar

36.

C. San Segundo 1988. Notas sobre la alimentacion del buho cicco (Asio otus) en Avila. Ardeola 35: 150–155. Google Scholar

37.

F. Saucy 1988. Dynamique de population, dispersion et organisation sociale de la forme fouisseuse du Campagnol terrestre (Arvicola terrestris scherman (Shaw), Mammalia, Rodentia). Thèse, Université de Neuchâtel. Google Scholar

38.

E. Schmidt 1971. Angaben über die relative Häufigkeit der Feldmaus (Microtus arvalis) in Ungarn, auf Grund von Gewölluntersuchungen der Waldohreule (Asio otus). Aquila 78/79: 189–196. (In Hungarian). Google Scholar

39.

E. Schmidt 1975. Die Ernährung der Waldohreule in Europa. Aquila 80/81: 221–238. Google Scholar

40.

B. Schmitz 1987. Nahrung und Phänologie einer Waldohreule (Asio otus) am Wintereinstand. Charadrius 23: 217–219. Google Scholar

41.

C. Smeenk 1972. Ökologische Vergleiche zwischen Waldkauz Strix aluco und Waldohreule Asio otus. Ardea 60: 1–71. Google Scholar

42.

G.M. Sutton 1926. Long-eared Owl capturing Ruffed Grouse. Auk 43: 236–237. Google Scholar

43.

J.M. Thiollay 1968. Le régime alimentaire de nos rapaces: quelques analyses françaises. Nos Oiseaux 29: 249–269. Google Scholar

44.

N. Tinbergen 1932. Über die Ernährung einer Waldohreulenbrut (Asio otus otus (L.)). Beitr. Fortpfl. Biol. Vögel 8: 54–55. Google Scholar

45.

D. Tome 1994. Diet composition of the Long-eared Owl (Asio otus) in Central Slovenia: Seasonal variation in prey use. J. Raptor Res. 28: 253–258. Google Scholar

46.

D. Tome 2000. Estimating individual weight of prey items for calculation of the biomass in the diet of Long-eared Owl (Asio otus): is it worth of extra effort. Folia Zool. 49: 205–210. Google Scholar

47.

D. Tome 2003. Functional response of the Long-eared Owl (Asio otus) to changing prey numbers: a 20-year study. Ornis Fenn. 80: 63–70. Google Scholar

48.

O. Uttendörfer 1939. Die Ernährung der deutschen Raubvögel und Eulen und ihre Bedeutung in der heimischen Natur. Neumann, Neudamm. Google Scholar

49.

O. Uttendörfer 1952. Neue Ergebnisse über die Ernährung der Greifvögel und Eulen. Ulmer, Stuttgart. Google Scholar

50.

W. van Manen 2001. Invloed van weersomstandigheden op gedrag en jaagsucces van overwinterende Ransuilen Asio otus. Limosa 74: 81–86. Google Scholar

51.

J.P. Veiga 1980. Alimentación y relaciones tróficas entra la Lechuza Común (Tyto alba) y el Búho Chico (Asio otus) en la Sierra de Guadarrama. Ardeola 25: 113–142. Google Scholar

52.

J.P. Veiga 1981. Variación annual de régime alimenticio y densidad de población de dos estrigiformes: sus causas. Doñana, Acta Vertebrata 8: 159–175. Google Scholar

53.

P. Vorisek , J. Votypka , K. Zwara & M. Svobodova 1998. Heteroxenous coccidia increase the predation risk of parasitized rodents. Parasitology 117: 521–524. Google Scholar

54.

H. Wijnandts 1984. Ecological energetics of the Long-eared Owl (Asio otus). Ardea 72: 1–92. Google Scholar

Appendices

SAMENVATTING

In dit literatuuronderzoek worden 475 publicaties met informatie over de voedselsamenstelling van de Ransuil Asio otus op een rij gezet. De gegevens van 312 publicaties werden in een database ingevoerd. Uiteindelijk werden 194 publicaties geselecteerd die een goed kwantitatief beeld van het voedsel gaven. In de publicaties tezamen ging het om 813 033 prooien die verdeeld waren over 477 verschillende prooitypes: 180 zoogdieren, 191 vogels, 15 reptielen, 7 amfibieën, 1 vissoort en 83 taxa van ongewervelde dieren. Kleine zoogdieren waren veruit de meest aangetroffen prooien (93,3% van de gewervelde prooien). Vogels werden veel minder vaak aangetroffen in het voedsel (6,4%). Het gewicht van de prooien lag tussen de 1 en 500 g, maar de meeste prooien waren lichter dan 50 g. Er waren 23 prooisoorten die in minstens één van de onderzoeken het grootste deel van het voedsel uitmaakten. De voedselsamenstelling op het niveau van familie van de prooidieren was vergelijkbaar in de verschillende regio's over de wereld, maar er waren grote verschillen op soortniveau.

Appendix 1.

In addition to the citations in the list of references, the following abbreviated citations reflect publications that contained Long-eared Owl Asio otus diet data which were input into the diet database for this project.

Ahlbom B. 1979. Calidris 8: 62–64.; Alegre J. et al. 1989. Doñana, Acta Vertebrata 16: 305–309.; Aloise G. et al. 1995. Avocetta 19: 110.; Amat J.A. et al. 1981. Alauda 49: 112–120.; Araujo J. et al. 1974. Ardeola 19: 397–428.; Armitage J.S. 1968. Naturalist (Leeds) 905: 37–46.; Armstrong W.H. 1958. Mich. State Univ. Publ. Mus. Biol. Ser. 1: 63–69.; Balčiauskien_ L. et al. 2006. Acta Zool. Litunica 16: 37–45.; Barbu P. 1978. An. Univ. Bucuresti 27: 101–104.; Barrows C.W.A.U. 1989. Western Birds 20: 1–10.; Bauer F. et al. 2005. Mitt. Ver. Sächs. Orn. 9: 527–531.; Bauschmann G. et al. 1984. Beitr. Naturkde Wetterau 4: 47–58.; Bellebaum J. 1995. Charadrius 31: 220–224.; Bergier P. et al. 1986. Faune Provance 7: 80–83.; Bethge E. 1982. Z. Säugetierkde 47: 215–219.; Bezzel E. 1972. Anz. Ornithol. Ges. Bayern 11: 181–184.; Bezzel E. et al. 1979. Garmischer Vogelkdl. Berichte 5: 32–38.; Block B. et al. 1990. Vogel und Umwelt 6: 29–37.; Bohác D. et al. 1970. Sylvia 18: 63–71.; Bohnsack P. 1973. Corax 4: 93–102.; Bon M. et al. 1998. Boll. Mus. Civico Storia Naturale Venezia Suppl. 48: 186–189.; Bosakowski T. et al. 1992. Can. J. Zool. 70: 984–992.; Brown N.L. 1995. J. Raptor Res. 29: 277–279.; Bruster K.-H. 1973. Hamburg. Avifaun. Beitr. 11: 59–84.; Busse H. 1965. Beitr. Vogelkde 10: 433–440.; Cahn A.R. et al. 1930. Auk 47: 323–328.; Capizzi D. et al. 1998. Terre Vie 53: 367–385.; Casini L. et al. 1988. Avocetta 12: 101–106.; Cecere F. et al. 2000. Hystrix 11: 47–53.; Chaline J. et al. 1974. Doin, Paris.; Chiba A. et al. 2005. Ornithol. Sci. 4: 169–172.; Cooke D. et al. 1995. Irish Bird 5: 305–307.; Corral J.F. et al. 1979. Doñana, Acta Vertebrata 6: 179–190.; Craig E.H. et al. 1985. Auk 102: 193–195.; Craighead J.J. et al. 1956. Stackpole Co, Harrisburg, Pennsylvania.; Cramp S. 1985. Oxford University Press, New York.; Dathe H. 1988. Beitr. Vogelkde 34: 41–46.; De Franceschi P. et al. 1987. Riv. Ital. Ornitol. 57: 151–154.; De Wavrin H. et al. 1991. Aves 28: 169–188.; Delgado G. et al. 1986. Doñana, Acta Vertebrata 13: 87–93.; Delmée E. et al. 1979. Le Gerfaut 69: 45–77.; Demange D. 1994. Milvus, Bull. 26: 44–47.; Dement'ev G.P. et al. 1951. Israel Programm für Scientific Translations, Jerusalem (1966).; Deppe H.J. 1979. Angew. Ornith. 5: 128–140.; Fairley J.S. 1967. Brit. Birds 60: 130–135.; Flade W. et al. 1985. Hamburg. Avifaun. Beitr. 20: 89–96.; Galeotti P. et al. 1994. J. Raptor Res. 28: 265–268.; Garcia A.M. et al. 2005. J. Raptor Res. 39: 445–453.; Gerdol R. et al. 1982. Riv. Ital. Ornitol. 52: 55–60.; Getz L.L. 1961. Wilson Bull. 73: 79–82.; Glue D.E. 1977. Brit. Birds 70: 318–331.; Glue D.E. et al. 1974. Brit. Birds 67: 361–369.; Goller S. 1977. Vogelkdl. H. Edertal Kreis Waldeck-Frankenberg 3: 7–36.; González A.G. et al. 2001. Ardeola 48: 75–80.; Gottschalk W. 1972. Beitr. Tierwelt Mark 9: 135–153.; Hädecke K. 1973. Apus 3: 32–34.; Haensel J. et al. 1966. Beitr. Vogelkde 11: 345–358.; Haensel J. et al. 1970. Naturkd. Jber. Mus. Heineanum 5/6: 83–98.; Hagen Y. 1965. Medd. Statens Viltundersøkelser 23: 1–43.; Handwerk J. 1990. Bonn. zool. Beitr. 41: 171–179.; Harmata W. 1969. Przeglad Zoologiczny 13: 98–101.; Hartwig E. et al. 1976. Vogelwelt 97: 175–190.; Hartwig E. et al. 1981. Hamburg. Avifaun. Beitr. 18: 121–148.; Hedrick P.W. et al. 1989. Occ. Papers Mus. Natural Hist., Univ. Kansas 133: 1–7.; Heitkamp U. 1967. Ornithol. Mitt. 19: 139–143.; Henrioux F. (1999). Thèse, Université de Neuchâtel.; Herzig L. et al. 1980. Beitr. Naturkde Osthessen 16: 127–131.; Hillarp J.-Å. 1971. Medd. Skånes Ornitol. Förening 10: 27–31.; Holt D.W. et al. 1991. J. Raptor Res. 25: 23–24.; Hölzinger J. 2001. Ulmer, Stuttgart.; Husson A.M. 1949. Bull. L.L. P.O. 29: 187–190.; Jäckel A.J. 1891. München.; Jensen A. 1968. Flora Fauna 74: 69–76.; Jentzsch M. 1992. Apus 8: 63–65.; Johnson N.K. 1954. Condor 56: 52.; Joschko M. 1978. Ornithol. Mitt. 30: 139–145.; Kahmann H. 1951. Ornithol. Mitt. 3: 121–124.; Källander H. 1977a. Vår Fågelvårld 36: 134–142.; Källander H. 1977b. Ornis Fenn. 54: 79–84.; Kawaguchi S. et al. 2003. Jap. J. Ornithol. 52: 29–31.; Kayser Y. et al. 1996. Nos Oiseaux 43: 485–496.; Klaas C. 1961. Natur und Volk 91: 81–88.; Klippel W.E. et al. 1982. J. Field Ornithol. 53: 418–420.; Knight R.L. et al. 1977. Murrelet 58: 2–6.; Koning F.J. 1985. Brit. Birds 78: 195–196.; Kramer H. 1932. Ber. Ver. Schlesischer Ornithol. 17: 3–6.; Kramer H. 1937. Beitr. Fortpfl. biol. Vögel 13: 67–70.; Kren J. 1987. In: Nero R.W. (eds.) US Department of Forest Service.; Krystufek B. 1980. Acrocephalus 1: 91–92.; Kumerloeve H. et al. 1953. Ornithol. Mitt. 5: 48–50.; Kumerloeve H. et al. 1954. Ornithol. Mitt. 6: 165–167.; Laiu L. et al. 1998. Trav. Mus. Hist. Naturelle “Grigore Antipa” 40: 413–430.; Laiu L. et al. 2002. Trav. Mus. Hist. Naturelle “Grigore Antipa” 44: 423–430.; Laiu L. et al. 2003. Trav. Mus. Hist. Naturelle “Grigore Antipa” 45: 365–372.; Lange L. 2004. Vogelkdl. Ber. Küste Binnenland 3: 141–142.; Lange R. et al. 1988. Lutra 31: 94–96.; Leboulenger F. et al. 1987. Cormoran 6: 137–154.; Lindberg A.J. 1978. Kingbird 28: 77–83.; Malavasi D. 1995. Suppl. Ric. Biol. Selvaggina 22: 255–256.; Manegold A. 2000. Säugetierkdl. Inform. 4: 483–490.; Manganaro A. 1997. Riv. Ital. Ornitol. 67: 151–157.; Marks J.S. et al. 1984. Ornis Scand. 15: 135–143.; Martina A. et al. 1999. Buteo Suppl.: 57.; März R. 1965. Beitr. Vogelkde 10: 338–348.; März R. et al. 1963. Beitr. Naturkde Niedersachsen 16: 69–74.; Maser C. et al. 1970. Murrelet 51: 29–33.; Matsuoka S. 1974. Misc. Rep. Yamashinia Inst. Ornith. 7: 324–329.; Medved A. 2005. Ciconia 13: 128–132.; Mezzavilla F. 1993. Lav. Soc. Venez. Sci. Nat. 18: 173–182.; Mienis H.K. 1994. Ornith. Soc. Middle East Bull. 32: 20–21.; Mildenberger H. 1982a. Kilda-Verlag, Greven.; Mildenberger H. 1982b. Düsseldorf.; Mlikovsky J. 1978. Apus 4: 79–80.; Morphy M. 1964. Ibis 107: 97–100.; Murariu D. et al. 1991. Trav. Mus. Hist. Naturelle “Grigore Antipa” 16: 415–420.; Murariu D. et al. 1982. Trav. Mus. Hist. Naturelle “Grigore Antipa” 24: 203–208.; Navarro J. et al. 2003. J. Raptor Res. 37: 256–258.; Nogales M. et al. 1986. Ardeola 33: 213.; Obuch J. 1989. Tichodroma 2: 49–65.; Obuch J. 1992. Tichodroma 4: 35–42.; Oeser R. 1974. Actitis 8: 66–67.; Okill J.D. et al. 1978. Shetland Bird Report 1977: 48–50.; Petrescu A. 1997. Trav. Mus. Hist. Naturelle “Grigore Antipa” 37: 305–317.; Pfeifer G. 2003. Husum, Husum.; Plini P. 1985. Riv. Ital. Ornitol. 55: 193–194.; Plini P. 1986. Avocetta 10: 41–43.; Randle W. et al. 1952. Ecology 33: 422–426.; Rey J.M. 1975. Ardeola 21: 415–420.; Reynolds R.T. 1970. Murrelet 51: 8–9.; Rockenbauch D. 1976. Anz. Ornithol. Ges. Bayern 15: 78–84.; Rodriguez F. 1987. Ardeola 34: 99–102.; Romanowski J. 1988. Polish Ecol. Studies 14: 223–234.; Roulin A. 1996a. Nos Oiseaux 43: 529.; Roulin (1996b): Nos Oiseaux 43: 289–294.; Salvati L. et al. 2001. Biota 2: 181–185.; Schimmelpfennig R. 1991. In: Stubbe M. (eds.) Halle.; Schmidt E. 1965. Zool. Abh. Mus. Tierkd. Dresden 27: 307–315.; Schmidt E. 1973. Aquila 76/77: 55–64.; Schnurre O. 1937. Märkische Tierwelt 2: 241–255.; Schnurre O. et al. 1962. Ornithol. Mitt. 14: 11–13.; Schnurre O. et al. 1975. Beitr. Vogelkde 21: 216–227.; Schnurre O. et al 1975. Milu 3: 742–747.; Schumann H. 1949. Vogelwelt 70: 38–41.; Scott T.G. 1948. Auk 65: 447–448.; Seçkin S. et al. 2005. Zoology in the Middle East 35: 102–103.; Siverio F. et al. 2002. Alauda 70: 421–422.; Smettan H.W. 1987. Ornith. J. hefte Bad. -Württ. 3: 1–52.; Šotnár K. et al. 1998. Buteo 10: 89–96.; South G.R. 1966. Brit. Birds 59: 493–497.; Spiker C.J. 1933. Wilson Bull. 45: 198; Stadie R. 1936. Ber. Ver. Schlesischer Ornithol. 21 Sonderdruck.; Stapp W.B. 1956. Audubon Magazine 58: 218–220.; Steiner H. 1961. Egretta 4: 1–19.; Stophlet J.J. 1959. Wilson Bull. 71: 97–99.; Sublimi Saponetti S. et al. 1991. Suppl. Ric. Biol. Selvaggina 17: 119–122.; Sueur F. 1980. L'Avocette 4: 33–37.; Sueur F. et al. 1999. Le syndicat mixte pour l'Aménagement de la côte Picarde, Abbeville.; Sulkava P. 1965. Aquilo Ser. Zool. 2: 41–47.; Temme M. 1990. Drosera 90: 133–140.; Ticehurst C.B. 1939. Ibis 3: 512–520.; Tirianda A. 1993. Tichodroma 5: 95–101.; Tome D. 2000. Acrocephalus 21: 3–7.; Triplet P. 1981. L'Avocette 5: 30–37.; Trujillo O. et al. 1989. Ardeola 36: 193–198.; Uttendörfer O. 1932. Nos Oiseaux 12: 189–192.; Veiga J.P. 1984. Rapinyaires Mediterranis 2: 256–264.; Viczian A. 1933. Ornithol. Mschr. Deutschen Vereins Schutze Vogelwelt 58: 173–182.; Village A. 1981. Bird Study 28: 215–224.; Voight J. et al. 1978. American Midland Naturalist 99: 162–171.; Vondrácek J. 1985. Zprávy MOS 43: 73–78.; Voous K.H. et al. 1988. Happer Collins, London.; Warthin A.S. et al. 1922. Auk 39: 417.; Weller M.W. et al. 1963. Iowa Stat J. Sci. 38: 151–160.; Wendland V. 1957. J. Ornithol. 98: 241–261.; Wendland V. 1984. Beitr. Vogelkde 30: 1–11.; Wooller R.D. et al. 1968. Bird Study 15: 164–166.; Yalden D.W. 1985. Bird Study 32: 122–131.; Yosef R. 1997. Sandgrouse 19: 148–149.; Zabel J. 1966. Natur und Heimat 26: 99–104.; Zabel J. 1970. Natur und Heimat 30: 90–94.; Zimmermann K. 1950. Vogelwelt 71: 152–155.; Zimmermann K. 1963. Beitr. Vogelkde 9: 59–68.; Zuccon D. 1997. Avocetta 21: 101.

Simon Birrer "Synthesis of 312 Studies on the Diet of the Long-Eared Owl Asio otus," Ardea 97(4), 615-624, (1 December 2009). https://doi.org/10.5253/078.097.0430
Published: 1 December 2009
JOURNAL ARTICLE
10 PAGES


SHARE
ARTICLE IMPACT
Back to Top