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Summary: The dynamics of parental investment throughout the nestling stage and the factors affecting it were studied in the Chough(Pyrrhocorax pyrrhocorax), a species whose patterns of apportioning parental care are largely unknown. The occurrence of important trade-offs between the sexes, among the different activities of parental care and between parents' survival and current offspring survival were estimated. The parental contributions of both sexes were assessed mainly in terms of food provisioning rate and nest attendance time. Only the female brooded young nestlings while the two sexes contributed equally in food deliveries and nest sanitation. Nestling age greatly affected nest attendance time. The female spent a long time brooding in the first 10 days after hatching. Both sexes increased attendance towards the end of the nestling stage. Conversely, feeding rate and feeding rate per nestling remained approximately constant throughout the nestling period. Nestlings in smaller broods received more feeding visits than those in larger broods. The shape of the per-nestling feeding rate curve was ‚concave-up', supporting Nur's (1984) ‚trade-offs model' rather than the Lack-Gibb hypothesis. Maintaining a high feeding frequency in broods already above the modal value might be disadvantageous, implying few benefits and large energy costs (i.e. the reduction of the parents' residual reproductive value). Female brooding time in relation to brood size showed the same decreasing ‚concave-up' trend line. Short-term trade-offs proved to be important determinants of the dynamics of parental care. Specifically, the distance from the feeding areas greatly affected the delivery rate: pairs spent a disproportionately longer time foraging in more distant patches than in closer ones. Diurnal variations and changes owing to weather conditions were also examined. [ABSTRACT FROM AUTHOR]

The European landscape reflects many centuries of dynamic interaction between people and their natural environments. Indeed, much of the current biological and aesthetic value of the wide variety of 'cultural' landscapes has been created and is now maintained by long-established farming systems. Such traditional systems (many of which are pastoral based) are generally well integrated with the environment and involve management practices that do not over-exploit the natural carrying capacity of the land. However, the rapid modernisation of agriculture that occurred after the 1939-1945 war resulted in an intensification of many European farming systems and has had severe negative effects on the environment. This modernisation initially occurred primarily in northwest Europe fuelled by the European Union (EU) Common Agricultural Policy (CAP), but with the expansion of the EU it is continuing and is certain to increase in southern, central, and eastern Europe. The response of the EU to this fundamental imbalance between farming and the environment has included the introduction of compulsoryregulations to ensure the implementation of minimum environmental standards in the production processes and the promotion of agri-environment programmes to encourage farmers to undertake positive environmental management on their farmland. The ongoing reforms of the CAP willundoubtedly place greater emphasis on agri-environment programmes and increasingly on the concept of 'integrated rural development.' There is, however, still a pressing need for detailed information to justify to the EU and world markets why certain types of farming system should be central to future European rural development policies. [ABSTRACT FROM AUTHOR]