Většina pěvců mírného pásu je monogamní pouze zdánlivě. Zkoumání paternity u různých druhů odhalilo ve značném množství hnízd nějaký podíl mláďat mimopárového původu. Pro samce je proto důležitá snaha mimopárovým kopulacím zabránit. Jednotlivé druhy pěvců volí různé strategie, např. časté kopulace nebo hlídaní partnerky. Při studiu agresivity samců lindušky luční (Anthus pratensis) na horských pláních v Krkonoších pomocí tzv. playbackových experimentů zaznamenala autorka neobvyklé chování. Zatímco samci bez přítomnosti samičky nad atrapou s reproduktorem vysílajícím zpěv pouze přelétali, v přítomnosti přihlížející samičky na atrapu někteří i fyzicky útočili. and Most temperate passerines are only apparently monogamous. Paternity research in various species has revealed that in a lot of broods some of the young are of extra-pair origin. Thus it is very important for males to prevent extra-pair copulation on the part of their females. During a study of aggressive male behaviour in the Meadow Pipit (Anthus pratensis) on mountain plains in the Giant Mts. using playback experiments, the author found an extraordinary behaviour. While males overflew a pipit model accompanied by an intra-specific song playback, in the presence of the female some of them attacked the model.
We tested the hypothesis that males of meadow pipits (Anthus pratensis) respond differentially to simulated territorial intrusions (song playback + bird model) by conspecific, related (tree pipit, Anthus trivialis), and unrelated individuals (willow warbler, Phylloscopus trochilus), and evaluated the effect of playback order. All tested males responded aggressively to the conspecific playback; reactions to heterospecific stimuli occurred only after previous excitation by the conspecific song and dummy, and were usually weaker. Apparently, although males were able to discriminate between playbacks, excitation by intrusion of a conspecific rival elicited an aggressive reaction to otherwise neutral stimuli. Reactions to heterospecific playbacks closely following the conspecific one did not differ significantly between congeneric and unrelated species. The response to a subsequent heterospecific stimulus, however, was taxon-dependent: congeneric species elicited a significantly stronger reaction than an unrelated one. We presume that this was due to the morphological similarity between pipits, and that the more intensive reaction could have been caused by stronger visual stimulus from the respective model. We discuss the potential benefits as well as limitations of using models (dummies) in playback experiments, and suggest that overexcitation by previous stimuli should be considered during experimental setup and data analysis in studies focusing both on interspecific aggressiveness and on neighbour-stranger interactions.