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The aim of this doctoral thesis is to synthesise data on Red Kite demography and distribution from Germany with current analytical methods, to increase the understanding of central demographic rates and to describe crucial influencing variables for the species’ breeding occurrence. Also, the impact of apparent strong philopatry on breeding occurrence and population development of Red Kites as well as the consequences of a propensity for delayed recruitment (‘floating’ behaviour) are currently not well understood. Although mortality of adult breeding individuals has by far the strongest impact on Red Kite population growth rates, demographic data and studies on age-specific survival rates are lacking – limiting the understanding of the species’ population trends. In comparison to other raptors and considering its intermediate size, the Red Kite is an extremely long-lived and highly social bird species – which strongly affects its demography and distribution. Red Kites are opportunistic scavengers in the agricultural landscape and the species has seen a changeful history of population increase and decline, strongly linked to human cultivation of farmlands and anthropogenic mortality. In contrast, some reintroduced or formerly marginal Red Kite populations, especially in in the UK, Switzerland and Sweden, showed increasing populations in recent years. Even within Europe, the distribution of the Red Kite is strongly restricted and the majority of the species’ breeding and wintering populations, especially in Germany and Spain, showed declines over the last decades. The Red Kite (Milvus milvus) is a European near-endemic raptor species and due to its limited distribution and small global population size in the focus of national and international conservation efforts. Additionally, low juvenile dispersal of Red Kites reduces recolonisation of unoccupied patches. The differences between actual and predicted distribution may stem from present or former high mortality rates which are not compensated for by current reproduction rates. Furthermore, a comparison of the predicted habitat suitability map with the actual distribution of Red Kites showed that not all suitable habitats were occupied by the species and thus, the species’ distribution seems not to be in equilibrium with its environment.
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The model revealed a strong relationship between land-use patterns and the Red Kite’s distribution. For the first time, an extensive data set was used for modelling comprising a sample size of 2,625 Red Kite breeding sites, high-resolution land-use data (10 m × 10 m) and climatic as well as topographic variables. In this study we analysed the effect of land use on the breeding distribution of Red Kites throughout Germany, the species’ core distribution area, using a distribution model. Currently, only little is known about the factors limiting both the global occurrence of the Red Kite and its distribution on regional scales. This entails the need for comprehensive knowledge of the birds’ ecology and distribution. Central Europe has the responsibility to protect the Red Kite Milvus milvus as it holds the majority (>50 % of all breeding pairs) of the global population.