Foraging and reproductive strategies of selected passerine birds

According to currently generally accepted model of evolutionary optimalization of parental investments, parental behavior should be balanced to bring the highest benefits (maximal expected value of progeny) with the lowest costs invested. This necessity establishes the pressure, which forces the organisms to balance their life-history strategies according to the changing environment. More than one solution frequently exists, and it may be crucial, which one is chosen in a given circumstances. This Ph.D. thesis deals with three passerine species and investigates their foraging, reproductive and antipredatory strategies, in the framework of "costs and benefits" theory of parental decisions and also in association with the phenomenon of synurbization. The paper by Kryštofková et al. (2006) "Parental foraging strategies and feeding of nestlings in Common Redstart Phoenicurus phoenicurus" inquires whether such factors as age of nestlings, their number, or sex of parents have influence on parental feeding frequency and foraging strategies (parameters of hunting in space and time); the literary data are controversial, even for one and the same passerine species. The male uses passive foraging mode more than female and as the nestlings grow older, the proportion of passive foraging mode is increasing, while..