Category Archives: Publication

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

Posted on by

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.

Back to scientific papers.

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

Posted on by

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.

Back to scientific papers.

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

Posted on by

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.

Back to scientific papers.

Neighbour recognition in two sister songbird species with a simple and complex repertoire – a playback study

Posted on by

2015

Pavel Jaška, Pavel Linhart, Roman Fuchs

DOI: 10.1111/jav.00482

Abstract:

The ability of individuals to recognize others based on vocalizations has been proven in many species of birds. However, we are still far from understanding important aspects of the discrimination process. For example, it is still not fully understood whether, and why, repertoire size hinders discrimination between individuals. Further, the strategies and vocal cues used for discrimination between individuals are largely unexplored. In this study, we tested the ability of chiffchaffs Phylloscopus collybita and willow warblers Phylloscopus trochilus, two closely related species with different repertoire sizes and song organization, to differentiate between their neighbours on the basis of a single song of a neighbouring male. We did playback experiments within the ‘dear enemy’ paradigm in which we tested resident males with a single song of a neighbour broadcast from the correct and opposite, incorrect territory border. Both species displayed a strong ability to discriminate between their neighbours representing further evidence that repertoire size per se has no negative impact on individual recognition in songbirds. Using a single song for playback allowed us to speculate about the nature of the possible cues used by males for recognition. Individual recognition in both species is most likely based on the modulation of syllables or on general voice characteristics. We suggest that specific changes in song organization, for example the tendency of individuals to insert a distinct phrase at the beginning of each song, may facilitate individual recognition and compensate for increased repertoire size in willow warblers.

Back to scientific papers.

The role of body size in predator recognition by untrained birds

Posted on by

2015

Jana Beránková, Petr Veselý, Roman Fuchs

DOI: 10.1016/j.beproc.2015.09.015

Abstract:

It is supposed that body size serves as an important cue in the recognition of relevant stimuli in nature. As predators of varying body size pose differing levels of threat, their potential prey should be able to discriminate between them. We tested the reaction of great tits (Parus major) to the dummies of their common predator (the European sparrowhawk-Accipiter nisus) in natural and reduced body sizes under laboratory conditions. All of the tested dummies possessed local raptor-specific features (hooked beak, claws with talons, and conspicuous eyes), but differed in global species-specific features: body size (large – the size of a sparrowhawk, small – the size of a great tit) and colouration (sparrowhawk, great tit, robin, and pigeon). The sparrowhawk-coloured dummies evoked fear regardless of their size while both great tit- and pigeon-coloured dummies evoked no fear reaction. The body size was used as the cue only for the discrimination of the robin-coloured dummies. The differences in reactions to the dummies with robin colouration (species unimportant to the great tits) could be explained as that the tits are able to recognize these birds in nature, but not so undoubtedly as the predator or the conspecific.

Back to scientific papers.