Karel Šťastný

Habitat specialization of birds in the Czech Republic: comparison of objective measures with expert opinion

Capsule Expert‐based classification of bird species as habitat specialists and as generalists agrees with objective measures of species’ habitat requirements based on large‐scale monitoring data. Aims To compare habitat specialization of 137 common bird species breeding in the Czech Republic using three different measures and to test their relationships to species’ abundance and habitat associations. Methods Data on bird abundance and surveyed habitats were collected through a standardized monitoring scheme of common breeding species in the Czech Republic. From these data we calculated a quantitative species specialization index (SSI). Canonical correspondence analysis (CCA) was applied to calculate species’ habitat niche breadth and the level of association of each species to the main habitats. A panel of 11 local bird experts classified each species as habitat generalist or habitat specialist. Results Species classified as habitat specialists by expert opinion showed higher habitat specialization according to the SSI, as well as according to CCA‐based habitat niche breadth. These species were also more closely associated with one of the main habitat types. These relationships were significant even after controlling for abundance. Conclusions As expert opinion accords with the level of species’ habitat specialization expressed using two quantitative objective measures, we suggest that these characteristics reflect real interspecific variation in the breadth of habitat requirements in birds. Interspecific differences in habitat specialization are not caused solely by the variability in abundance among species.

Changes in bird community composition in the Czech Republic from 1982 to 2004: increasing biotic homogenization, impacts of warming climate, but no trend in species richness

AbstractRecent major environmental changes could lead to homogenization in the composition of plant and animal communities, with generalist species replacing more specialized species, as well as to the increased domination of species adapted to warmer climatic conditions. Using common bird monitoring data, we have tested whether these patterns can be observed in the long-term changes in the structure and species richness of bird communities in the Czech Republic. We focused on a comparison of two time periods (1982–1990 and 1991–2004) that differ in land use (high agricultural intensity in the former, and a drop in agricultural intensity accompanied by forest expansion in the latter). We found that bird communities became less specialized and that this decline in specialization did not change after 1990. In contrast, taxonomic homogenization increased during the first time period but declined at the beginning of the second one. Moreover, the community composition developed towards a dominance of species breeding in warmer climates, and this change coincided with an increase in spring temperatures. Therefore, it would appear that both functional and taxonomic homogenization took place in the 1980s but the latter did not continue in subsequent decades. Species richness of local bird communities did not show any trend over time. We suggest that climate warming might be an important driving force of changes in the bird community composition in the Czech Republic, but the role of land-use changes is less clear, although it is probable that habitat specialists probably did not benefit from lower intensity of agricultural activities and increased forest cover.ZusammenfassungÄnderungen in der Zusammensetzung von Vogelgemeinschaften in der Tschechischen Republik zwischen 1982 und 2004: zunehmende biotische Vereinheitlichung, Einfluss von Klimaerwärmung, aber kein Trend im Artenreichtum Aktuelle große Veränderungen in der Umwelt könnten zu einer Vereinheitlichung der Zusammensetzung von Tier- und Pflanzengemeinschaften führen, wobei Generalisten die spezialisierteren Arten ersetzen und Arten dominieren, die an wärmere Klimate angepasst sind. Anhand normaler Vogel-Monitoring Daten testen wir in dieser Studie, ob sich diese Muster in langfristigen Veränderungen in der Struktur und dem Artenreichtum der Vogelgemeinschaften in der Tschechischen Republik beobachten lassen. Wir konzentrieren uns auf einen Vergleich zwischen zwei Zeiträumen (1982–1990 und 1991–2004), die sich in der Landnutzung unterscheiden (intensive Landwirtschaft im früheren und ein Absinken der Intensität der Landnutzung begleitet von einer Ausbreitung von Waldgebieten im letzteren). Wir fanden, dass die Vogelgemeinschaften weniger spezialisiert wurden, und diese Abnahme der Spezialisierung änderte sich nicht nach 1990. Dagegen stieg die taxonomische Vereinheitlichung während des ersten Zeitraums an, nahm aber am Beginn des zweiten wieder ab. Darüber hinaus entwickelte sich die Zusammensetzung der Gemeinschaft hin zu einer Dominanz von Arten, die ihre Brutgebiete in wärmeren Klimaten haben, und diese Änderung fiel zusammen mit einem Ansteigen der Frühlingstemperaturen. Daher scheint es, als hätten sowohl die funktionale als auch die taxonomische Vereinheitlichung in den 1980er Jahren stattgefunden, aber die erstere schritt später nicht fort. Der Artenreichtum lokaler Vogelgemeinschaften zeigte keinerlei Trend über die Zeit. Wir stellen zur Diskussion, dass die Klimaerwärmung eine treibende Kraft sein könnte für Änderungen in der Zusammenstellung der Vogelgemeinschaft in der Tschechischen Republik, jedoch ist die Rolle der Landnutzung weniger klar. Arten, die auf ein bestimmtes Habitat spezialisiert sind, konnten wahrscheinlich nicht profitieren von der weniger intensiven Landnutzung und der Zunahme der Wälder.

Changes in bird distribution in a Central European country between 1985–1989 and 2001–2003

European birds have been significantly affected by dramatic environmental changes during the last decades. The effects of these changes on species richness and distribution in particular countries are still poorly understood because of a lack of high-quality, large-scale data standardized over time. This is especially true in Central and Eastern Europe. On a model group of birds in the Czech Republic (countrywide atlas mapping data), we examined whether long-term changes of species richness and distribution between 1985–1989 and 2001–2003 differed among groups of species defined by their habitat requirements, type of distribution in Europe, migratory strategy and the degree of national legal protection. Further, we investigated the effects of colonizers and local extinctions on these changes. Whereas the number of species in the whole country remained the same in both periods (208 species), species composition had changed. Increasing occupancy (i.e., number of occupied mapping squares) was observed in species of forest and wetland habitats, in short-distance migrants and in non-protected species. Southern species also positively changed their occupancy, but this pattern disappeared after the inclusion of six species dependent on extensively cultivated farmland that went extinct between mappings. The overall occupancy of all species together showed positive changes after excluding colonizers and extinct species. We suggest that the improvement of environmental conditions after 1990 caused the stability of or increased the distribution of common birds in the Czech Republic, and it was the disappearance of specific farmland practices that might have caused the loss of several species.

Mitochondrial DNA sequence variation and evolution of Old World house mice (Mus musculus)

Abstract. We analyzed sequences of two variable segments of the mitochondrial control region (CR) and flanking regions in the house mouse (Mus musculus). Most of the material was sampled from the eastern Mediterranean and the Middle East, i.e., a source area for the colonization of Europe. These sequences were supplemented with other samples from the whole range of the species including the Yemeni island of Socotra. This island was shown to harbour mice bearing M. m. domesticus and M. m. castaneus CR haplotypes. In addition, we found 10 distinct sequences at the same locality that were markedly different from all known CR sequences. Sequencing of the whole mitochondrial genome suggested these sequences to represent nuclear fragments of the mitochondrial origin (numts). We assessed genetic variation and phylogeography within and among the house mouse subspecies and estimated the substitution rate, coalescence times, and times of population expansion. We show the data to be consistent with time dependency of substitution rates and recent expansion of mouse populations. The expansion of European populations of M. m. musculus and M. m. domesticus estimated from the CR sequences coincide with presumed time of colonization of the continent in the Holocene.

Relationships between winter temperature and breeding bird abundance on community level: importance of interspecific differences in diet

Abstract. Winter weather limits populations of resident bird species. Although many small-scale or speciesspecific studies illustrated this fact, our knowledge of interspecific differences in population responses to winter temperatures is incomplete due to lack of community-level studies. For this purpose, we have used long-term monitoring data on breeding bird populations of 37 common bird species wintering in the Czech Republic. We predicted that species will differ in their relationship between winter temperature and abundance with respect to their body mass and dietary niche. Smaller species having relatively higher energy expenditure should show closer relationship between breeding abundance and winter temperature than larger species. Concerning dietary niche, abundance of species feeding on animals should be more affected by temperature than abundance of species feeding on plants or omnivorous species. Our results confirmed the second prediction: populations of species preying on animals followed winter temperatures more closely than populations of species feeding on both animals and plants. Food-mediated mortality is probably more important than direct effects of low temperatures. In general, relationships between abundance and temperature were relatively weak in most species and we suggest that possible changes in winter temperatures may not seriously affect populations of common breeding birds in the Czech Republic.

Numbers of wintering waterbirds in the Czech Republic: long-term and spatial-scale approaches to assess population size

Capsule Two nationwide monitoring schemes, the International Waterbird Census (IWC) and Atlas of Wintering Birds (AWB), provide comparable estimates of national population sizes of wintering waterbirds. Differences between these estimates for several species can be explained by differences in their migratory strategy. Aims We tested whether species-specific variables, i.e. the total numbers, distribution and migration strategy affected the accuracy of wintering population estimates provided by two different monitoring schemes, the IWC and AWB. Methods Estimates of the numbers of 81 waterbird species are compared, using data from IWC (mid-January) and AWB (December, January and February) in the Czech Republic between 1982 and 1985. Log-linear Poisson regression analysis was used to estimate missing IWC data from long-term IWC data series (1966–2013) using Trends and Indices for Monitoring data software. A series of generalized linear models was estimated to analyse the effect of species-specific variables on the presence of overlap between IWC and AWB national population estimates. Results The range of numbers recorded by IWC data overlap the range of AWB numbers in 22 of the 53 investigated species recorded by both monitoring schemes. Numbers of most other species based on the IWC counts were lower when compared with those generated from AWB data and included several widespread species, e.g. White-tailed Eagle Haliaeetus albicilla and White-throated Dipper Cinclus cinclus. In contrast, population size estimates based on IWC counts were higher than those generated from AWB estimates for one species, the Ferruginous Duck Aythya nyroca. The differences between IWC and AWB estimates were significantly higher in late-departing and early-arriving migrants. There was no effect of species distribution and population size. Conclusions Based on a single-country data sample, we support the relevance of the IWC Census methodology to produce estimates of wintering waterbird numbers and to calculate 1% thresholds for waterbird species, which we use to indicate nationally important wetland sites for future conservation and protection in the Czech Republic.

Refugial role of urbanized areas and colonization potential for declining Crested Lark (Galerida cristata) populations in the Czech Republic, Central Europe

Urban environment is only rarely considered an exclusive refuge for rapidly declining bird species. Crested Lark (Galerida cristata) is a species in Central Europe whose synanthropization began in the second half of the twentieth century due to dramatic changes in agriculture and landscape structure. We analyze how changes in these distribution patterns mirror landscape structures and demonstrate colonization potential from adjacent refuges. We used the Czech Breeding Bird Atlas data from two periods, 1985–1989 and 2001–2003, to model distribution change patterns for Crested Larks in two parts of the country, Bohemia and Moravia. Mapping quadrats comprised the sampling units, and binomial species presence or absence was used to model the change patterns using generalized linear models while considering landscape structure, demographic data and dominant habitat attributes as predictors. Despite similar attributes of landscape structures in Bohemia and Moravia, Crested Larks clearly differed in their extinction patterns. Within isolated Bohemia, the remnant subpopulations were restricted to early successional stands around commercial areas in urban zones. In Moravia, only altitude appeared related to the species’ disappearance. Moravia is connected at the south to the Pannonian Plain with stable or increasing Crested Lark populations, which we consider responsible for the significantly higher number of newly occupied quadrats in Moravia. Our results indicate the more isolated Bohemian population is more prone to extinction than is the Moravian population with its greater colonization potential. The study notes a rare example of urban zones serving as refuges for a bird species demanding early successional stands.ZusammenfassungDie Rolle verstädterter Bereiche als Zufluchtsgebiete und das Besiedlungspotenzial für Populationen der Haubenlerche (Galerida cristata) in Tschechien, Mitteleuropa Eine städtische Umwelt wird nur selten als exklusives Zufluchtsgebiet für rapide abnehmende Vogelarten betrachtet. Die Haubenlerche (Galerida cristata) ist eine Art in Mitteleuropa, deren Synanthropisierung in der zweiten Hälfte des 20. Jahrhunderts aufgrund dramatischer Veränderungen von Landwirtschaft und Landschaftsstruktur begann. Wir analysieren, inwieweit Veränderungen in diesen Verbreitungsmustern Landschaftsstrukturen widerspiegeln, und zeigen das Besiedlungspotenzial von benachbarten Zufluchtsgebieten auf. Wir haben Daten aus dem tschechischen Brutvogelatlas für zwei Zeiträume, 1985–1989 und 2001–2003, verwendet, um Veränderungen in den Verbreitungsmustern von Haubenlerchen in zwei Landesteilen, Böhmen und Mähren, zu modellieren. Die Erfassungseinheiten bestanden aus Kartierungsquadraten, und die binomiale An- oder Abwesenheit der Art wurde benutzt, um die Veränderungsmuster mit Hilfe generalisierter linearer Modelle zu modellieren, mit Landschaftsstruktur, demographischen Daten und dominanten Habitateigenschaften als Vorhersagevariablen. Trotz ähnlicher Merkmale von Landschaftsstrukturen in Böhmen und Mähren unterschieden sich Haubenlerchen deutlich in ihren Aussterbemustern. Im isolierten Böhmen waren die übriggebliebenen Subpopulationen auf frühe Sukzessionsflächen um städtische Gewerbegebiete herum begrenzt. In Mähren schien lediglich die Höhenlage mit dem Verschwinden der Art in Verbindung zu stehen. Mähren ist im Süden mit der Pannonischen Tiefebene verbunden, wo Haubenlerchenpopulationen stabil sind oder zunehmen, was wir für die signifikant höheren Anzahlen neu besiedelter Quadrate verantwortlich machen. Unsere Ergebnisse deuten darauf hin, dass die stärker isolierte böhmische Population eher Gefahr läuft auszusterben als die Population in Mähren mit ihrem größeren Besiedlungspotenzial. Diese Studie stellt ein seltenes Beispiel für Stadtzonen dar, die als Zufluchtsgebiete für eine Vogelart dienen, die auf frühe Sukzessionsflächen angewiesen ist.

Home range size of Tengmalm’s owl during breeding in Central Europe is determined by prey abundance

Animal home ranges typically characterized by their size, shape and a given time interval can be affected by many different biotic and abiotic factors. However, despite the fact that many studies have addressed home ranges, our knowledge of the factors influencing the size of area occupied by different animals is, in many cases, still quite poor, especially among raptors. Using radio-telemetry (VHF; 2.1 g tail-mounted tags) we studied movements of 20 Tengmalm’s owl (Aegolius funereus) males during the breeding season in a mountain area of Central Europe (the Czech Republic, the Ore Mountains: 50° 40’ N, 13° 35’ E) between years 2006–2010, determined their average hunting home range size and explored what factors affected the size of home range utilised. The mean breeding home range size calculated according to 95% fixed kernel density estimator was 190.7 ± 65.7 ha (± SD) with a median value of 187.1 ha. Home range size was affected by prey abundance, presence or absence of polygyny, the number of fledglings, and weather conditions. Home range size increased with decreasing prey abundance. Polygynously mated males had overall larger home range than those mated monogamously, and individuals with more fledged young possessed larger home range compared to those with fewer raised fledglings. Finally, we found that home ranges recorded during harsh weather (nights with strong wind speed and/or heavy rain) were smaller in size than those registered during better weather. Overall, the results provide novel insights into what factors may influence home range size and emphasize the prey abundance as a key factor for breeding dynamics in Tengmalm’s owl.

Alloparental care and adoption in Tengmalm’s Owl (Aegolius funereus)

AbstractFew cases of adoption have been reported in solitary breeding raptors, and in owls adoption has only been reported in two species. Here we report four cases of brood-switching of juvenile Tengmalm’s Owls (Aegolius funereus), recorded during and after the post-fledging dependence period using radio-telemetry, and a case of three orphaned siblings (one nestling and two fledglings) originally from one nestbox successfully fostered to another one. A possible evolutionary context of the brood-switching is discussed.ZusammenfassungAlloparentale Brutpflege und „Adoption“ beim Raufußkauz (Aegolius funereus) Fälle von Adoption bei solitär brütenden Greifvögeln sind nur selten beschrieben worden und bei den Eulen bisher auch nur für zwei Arten. Wir berichten hier von vier Fällen von Brut-Vertauschens bei jungen Raufußkäuzen (Aegolius funereus), die während und nach des Ausfliegens per Radiotelemetrie verfolgt wurden. Ferner beschreiben wir den Fall von drei verlassenen Jungen (eines noch im Nest, die anderen beiden gerade flügge geworden), die erfolgreich von einem Nistkasten in einen anderen umgesetzt und weiter gefüttert worden wurden. Mögliche evolutionsbiologische Zusammenhänge des Brutvertauschens werden diskutiert.

Factors Affecting Growth of Tengmalm's Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order.

In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm’s owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl’s main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species.