Assessment of relative mortality rates for two rapidly declining farmland owls in the Czech Republic (Central Europe)

  • Martin ŠálekEmail author
  • Karel Poprach
  • Libor Opluštil
  • David Melichar
  • Jakub Mráz
  • Radovan Václav
Original Article


Anthropogenic mortality has a considerable impact on populations of long-lived species, such as raptors, which increasingly inhabit human-dominated landscapes. Here, we analyzed long-term mortality data for two rapidly declining owls, Little Owl Athene noctua and Barn Owl Tyto alba, in the Czech Republic. We evaluated relative mortality rates with respect to owl age, month of carcass recovery, and two time periods (before and after year 2000). We examined 961 mortality records (199 Little Owls and 762 Barn Owls) derived from six distinct database sources totally spanning the period of years 1934–2017 and the entire Czech Republic. Natural causes, entrapment in vertical hollow objects and drowning in liquid reservoirs (entrapment), and collision with vehicles accounted for the highest proportion of mortality cases in Little Owl, while collision with vehicles and entrapment represented the most important mortality sources in Barn Owl. Relative mortality rates in Little Owl caused by entrapment, non-vehicle collision, electrocution at power lines and confinement in buildings increased after the year 2000. In turn, the relative mortality rate due to collision with vehicles increased after 2000 in Barn Owl. Persecution, collision with vehicles, and entrapment accounted for higher relative mortality rates in first-year than adult Little Owls. In Barn Owls, higher relative mortality rates due to collision with vehicles and entrapment were detected in adult compared to first-year birds. Finally, relative mortality rates differed between age classes according to the month of carcass recovery for both species. For Little Owl, the highest relative mortality rates in first-year individuals were detected during July and September, whereas adult Little Owls suffered the highest relative mortality rates during March, November and December. In Barn Owls, the relative mortality rates of first-year individuals peaked in November and December, whereas adult birds suffered the highest relative mortality rate during July, January and February. This study strongly suggests that reducing the risk of anthropogenic mortality may be crucial to halt the decline of Little Owl and Barn Owl populations.


Urbanization Anthropogenic mortality Entrapment Traffic Seasonal changes Population decline Mitigation measures Little Owl Barn Owl 



We would like to thank Jaroslav Cepák (Bird Ringing Centre, National Museum Prague), Zdeňka Nezmeškalová (Czech Union for Nature Conservation) for assistance with accessing the ringing records or data from rescue centers in the Czech Republic. We are very grateful to all ringers and members of “Working group on protection and research of birds of prey and owls in the Czech Republic”, especially Libor Schröpfer, Karel Makoň, Petr Berka, Miroslav Bažant, František Krause and Jiří Vlček for providing data. We also would like to thank Ronald van Harxen for providing photos of Little Owl mortality and David H. Johnson for correcting the English. Two anonymous reviewers provided helpful comments on early drafts of the manuscript. This work was supported by the research aim of The Czech Academy of Sciences (RVO 68081766).

Supplementary material

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.The Czech Academy of SciencesInstitute of Vertebrate BiologyBrnoCzech Republic
  2. 2.Faculty of Environmental SciencesCzech University of Life Sciences PraguePragueCzech Republic
  3. 3.Czech Society of OrnithologyPragueCzech Republic
  4. 4.Faculty of Science, Department of Development and Environmental StudiesPalacký UniversityOlomoucCzech Republic
  5. 5.TYTO, z. sVěrovanyCzech Republic
  6. 6.Podolí 286Podolí u BrnaCzech Republic
  7. 7.Český svaz ochránců přírodyBřeclavCzech Republic
  8. 8.NýřanyCzech Republic
  9. 9.TřeboňCzech Republic
  10. 10.Slovak Academy of SciencesInstitute of ZoologyBratislavaSlovakia

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