Monthly Archives: May 2017

The role of key features in predator recognition by untrained birds

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2014

Jana Beránková, Petr Veselý, Jana Sýkorová, Roman Fuchs

DOI: 10.1007/s10071-014-0728-1

Abstract:

The most important role in the recognition and categorization of predators (as well as other animals) is usually attributed to so-called key features. Under laboratory conditions, we tested the role of yellow eyes (specific for the genus Accipiter in European raptors) and hooked beak (common for all European birds of prey) in the recognition of the sparrowhawk (Accipiter nisus) by untrained great tits (Parus major) caught in the wild. Using wooden dummies, we interchanged either one of these potential key features or the body of the sparrowhawk (predator) and domestic pigeon (harmless bird). The tested tits showed three types of behaviour in the presence of the dummies: fear, interest without fear, and lack of interest. Eye interchange lowered fear of the sparrowhawk, but did not cause fear of the pigeon. Beak interchange did not lower fear of the sparrowhawk. Eye interchange caused increased interest in both species. Thus, a specific sparrowhawk feature is necessary for correct sparrowhawk dummy recognition but a general raptor feature is not. On the other hand, a specific sparrowhawk feature on a pigeon dummy is not enough to prompt sparrowhawk recognition. Thus, key features play an important, but not exclusive, role in predator recognition. An increased interest in some of the modified dummies implies that the tits have a general concept of a sparrowhawk. The individual variability in behaviour of tits is discussed.

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Winter density and habitat preferences of three declining granivorous farmland birds: The importance of the keeping of poultry and dairy farms

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2015

Martin Šálek, Jan Havlíček, Jan Riegert, Marek Nešpor, Roman Fuchs, Marina Kipson

DOI: 10.1016/j.jnc.2015.01.004

Abstract:

Populations of granivorous farmland birds have dramatically declined during recent decades in many European countries. Winter conditions and consequently, survival rates of farmland bird species during this critical period, are considered as one of the main causes of this negative trend. However, the importance of different habitat structures and connected food sources for successful overwintering in bird species has gained little attention so far in the Czech Republic. In this study we aimed to examine the role of habitat composition and food availability on winter distribution and abundance of three declining sedentary and granivorous bird species. During the winters 2009–2014, 149 villages in the Czech Republic were monitored for distribution and density of three farmland seed-eaters. House Sparrow was the most dominant species (88.6% of villages occupied; 4.32 ± 4.67 ind./100 m of transect), followed by Tree Sparrow (67.1% villages occupied; 1.83 ± 3.53 ind./100 m of transect) and Collared Dove (65.8% villages occupied; 0.72 ± 1.51 ind./100 m of transect). Occurrence of House and Tree Sparrow was significantly affected by the number of instances of poultry keeping. In both species, occupied villages showed a higher number of instances of poultry keeping. We did not find any such significant relationship for Collared Dove. Density of House Sparrow was significantly higher in villages with dairy farms, but we failed to find this relationship for Tree Sparrow and Collared Dove. Habitat preferences were similar for all three studied species. They positively responded to the proportion of shrubs/trees, the keeping of poultry, dairy farms and they avoided houses, arable land and grasslands. We conclude that poultry keepings and dairy farms can be important for studied species during the winter since they offer high food availability and good protection against predators. This suggestion is supported by the fact that long-term population decline has coincided with a long-term reduction in the keeping of poultry and dairy farms in the Czech Republic during the last 50 years.

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Surface texture plays important role in predator recognition by Red-backed Shrikes in field experiment

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2015

Michal Němec, Michaela Syrová, Lenka Dokoupilová, Petr Veselý, Petr Šmilauer, Eva Landová, Silvie Lišková, Roman Fuchs

DOI: 10.1007/s10071-014-0796-2

Abstract:

We compared the responses of the nesting red-backed shrikes (Lanius collurio) to three dummies of a common nest predator, the Eurasian jay (Garrulus glandarius), each made from a different material (stuffed, plush, and silicone). The shrikes performed defensive behaviour including attacks on all three dummies. Nevertheless, the number of attacks significantly decreased from the stuffed dummy through the plush dummy and finally to the silicone dummy. Our results show that wild birds use not only colours but also other surface features as important cues for recognition and categorization of other bird species. Moreover, the silicone dummy was attacked only when presented after the stuffed or plush dummy. Thus, we concluded that the shrikes recognized the jay only the stuffed (with feathered surface) and plush (with hairy surface) dummies during the first encounter. Recognition of the silicon dummy (with glossy surface) was facilitated by previous encounters with the more accurate model. This process resembles the effect of perceptual priming, which is widely described in the literature on humans.

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Song pitch indicates body size and correlates with males' response to playback in a songbird

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2015

Pavel Linhart, Roman Fuchs

DOI: 10.1016/j.anbehav.2015.01.038

Abstract:

The inverse relationship between body size and vocalization pitch has been described in a number of species. Nevertheless, the existence of size–pitch allometry within any songbird species is surprising due to the small size variation between males, the determinate growth and exceptional vocal prowess of the taxon. The phenomenon has been documented in only a few songbird species so far and the consequences of allometry remain unclear in this taxonomic group. In this study, we provide evidence that song spectral features are related to one of the body size components (tarsus length) even in a very small songbird species: the willow warbler, Phylloscopus trochilus. Moreover, the response of territorial males was affected by the pitch asymmetry between the subject and the playback stimulus: the lower-pitched the subject’s song in respect to the stimulus the bolder was its response. Our results suggest that willow warbler males may use song pitch to assess the body size of their rivals (i.e. their fighting ability) in male–male competition for resources.

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Diverse vegetation in a spa town supports human social benefits of urban birds

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2015

Tomáš Kučera, Petra Kloubcová, Petr Veselý

DOI: 10.1007/s10531-015-0974-9

Abstract:

The urban–rural gradient effect, together with the value of urban green patches, on saving bird diversity has received significant research in recent years. These topics are usually studied in the context of big cities, where the effects are more pronounced. In the present study, we observed how these phenomena affect the avicoenoses in smaller spa town, where landscape protection supports the benefits of biocultural diversity. We assessed the effect of the occurrence of microhabitats (especially particular tree and shrub forms) within the urban–rural gradient on bird fauna composition. We found that the urban–rural gradient in towns is not as relevant as in cities because the effect is covered with a more complicated multi-layered vegetation structure. For the management practices we confirm the high importance of vegetation continuity from the periphery to the city centre, bypassing the isolation of green patches. A proportion of deciduous and coniferous trees and their spatial heterogeneity are important for the occurrence of small songbirds. Next, we conducted a questionnaire-based study with the park visitors and found that there is a biocultural benefit from the presence of songbirds in large urban parks, especially in the spa town. The clear preference of songbirds by park visitors highlights the social benefit of bird diversity.

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