Monthly Archives: May 2017

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

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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.

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The role of body size in predator recognition by untrained birds

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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.

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Birds at the winter feeder do not recognize an artificially coloured predator

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2016

Petr Veselý, Markéta Buršíková, Roman Fuchs

DOI: 10.1111/eth.12565

Abstract:

It is supposed that coloration may affect the recognition of predators by prey species; nevertheless, the significance of the coloration and its particular components in the recognition process remains unknown. We presented dummies of the European sparrowhawk (Accipiter nisus) with changed body coloration, but with all other typical features preserved (body size and shape, beak, eyes, legs), to great tits (Parus major) and blue tits (Cyanistes caeruleus) visiting a winter feeder. A pigeon (Columba livia f. domestica) dummy was used as a harmless control. Neither tit species showed passive avoidance in the presence of a dummy with an artificial, violet-white chequered coloration. They obviously did not consider such an object to be a predator despite the presence of the raptor beak, eyes and talons. Sparrowhawk dummies with the coloration completely changed (altered with those of a harmless European robin) or with the typical colour feature removed (barred pattern on the underparts) were considered to be as dangerous as the unmodified sparrowhawk. We discuss the possibility that the effect of salient raptor-like features such as beak shape, eye coloration, and leg and talons shape overwhelmed the effect of body coloration in these cases. Birds visiting the feeder probably were able to generalize the vigilance towards the sparrowhawk to other realistically coloured dummies, but not to the non-natural dummy.

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Facing a Clever Predator Demands Clever Responses - Red-Backed Shrikes (Lanius collurio) vs. Eurasian Magpies (Pica pica)

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2016

Michaela Syrová, Michal Němec, Petr Veselý, Eva Landová, Roman Fuchs

DOI: 10.1371/journal.pone.0159432

Abstract: Red-backed shrikes (Lanius collurio) behave quite differently towards two common nest predators. While the European jay (Garrulus glandarius) is commonly attacked, in the presence of the Eurasian magpie (Pica pica), shrikes stay fully passive. We tested the hypotheses that this passive response to the magpie is an alternative defense strategy. Nesting shrikes were exposed to the commonly attacked European kestrel (Falco tinnunculus) in a situation in which i) a harmless domestic pigeon, ii) a commonly attacked European jay, and iii) a non-attacked black-billed magpie are (separately) presented nearby. The kestrel dummy presented together with the magpie dummy was attacked with a significantly lower intensity than when it was presented with the other intruders (pigeon, jay) or alone. This means that the presence of the magpie inhibited the shrike’s defense response towards the other intruder. These results support our previous hypotheses that shrikes use an alternative defense strategy in the magpie’s presence. We hypothesize that the magpie is able to associate the active defense of the shrikes with the close proximity of a nest and that shrikes try not to draw the magpie’s attention to the nest. The reason why this strategy is not used against the jay remains unanswered as jays as well as magpies show very similar cognitive and foraging skills enabling them to individuate the nest presence according to active parental defense.

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Disentangling the influences of habitat availability, heterogeneity and spatial position on the species richness and rarity of urban bird communities in a central European city

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2016

Michal Ferenc, Ondřej Sedláček, Jindra Mourková, Alice Exnerová, Jaroslav Škopek, Jiří Formánek, Roman Fuchs

DOI: 10.1007/s11252-016-0558-9

Abstract:

The prominent role of the absolute amount of (semi)natural habitats on urban avifauna richness is well documented; however the relative role of habitat availability, heterogeneity and spatial position at the scale of a whole city has not been investigated so far. The main objective of this study was to evaluate the relative influence of these variables on the species richness and rarity value of bird communities in the city of Prague, Czech Republic. We used three modes to describe the urban environment, resulting in different habitat category resolutions. Coarse habitat descriptors were good enough for predicting species richness, but a more detailed resolution was better in explaining the distribution of communities comprising rarer species. The availability of wooded habitats was consistently the most important variable explaining both richness and rarity of bird communities. Habitat heterogeneity enhanced species richness, especially in highly urbanized areas where wooded habitats were scarce. However, rarer species responded to habitat heterogeneity only weakly. The influence of grid cell spatial position on bird community richness was overridden by the impacts of habitat availability and heterogeneity. However, communities comprising rarer species tended to breed at peripheral sites encompassing open habitats and large woodlands. The preservation of sufficient wooded habitats including small patches remains the key tool for bird conservation in cities, and habitat heterogeneity should be supported in areas with less than ca. 3 % of wooded habitats. Rarer species benefit from the maintenance of more extensive patches of greenery in peripheral urban areas.

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