Tesis doctoral de Francisco Atienzar Navarro
Tits (paridae) are one of the most and better passerines known owing to they are broadly distributed, breeding in different habitats from gardens to forests, and they make use of nest boxes for breeding. Hence, such species are ideal for comparative studies on a large geographical scale. Despite the great amount of information concerned to tits, we still do not really understand life-history strategies of birds living under most ecological conditions. the present thesis is focused on achieving a better understanding of how birds are adapted to their environment. In particular, to examine the existence and the consequences of food limitation in mediterranean evergreen habitats, through an adequate knowledge of the constraints affecting both feeding behaviour and breeding success. To achieve the main objectives proposed, studies were conducted in three mediterranean ecosystems: pine and holm oak quercus ilex forests, and an orange grove. This was carried out mainly over great tits parus major, and in certain cases over crested tits lophophanes cristatus and coal tits periparus ater. The specific aims pursued in this thesis are as follows: a) searching for cues triggering the reproduction: how do birds use such cues? Consequences of food mistiming. b) are birds optimising clutch size within a population? c) identifying and describing factors affecting feeding behaviour. d) describing nesting places through vegetation structure: effects on breeding success. e) analysing some mechanisms of the coexistence among congeners. in the present thesis, it has been shown that birds used environmental temperature to cope with variation in food phenology, or they used vegetation characteristics to reduce predator detection. Birds also coped with some environmental and intrinsic factors when feeding chicks, by decreasing or increasing their effort. We have also showed how birds traded-off conflicting demands, for instance, between bird colouration and nest predation. Colourful females avoided nest predation by choosing concealed places. Additionally, we have shown how crested tits breeding in an untypical forest coped with the new environmental conditions by looking for nest boxes surrounded by pine trees. Finally, the three tit species used here coped with the problem of sharing the same habitat by differing in prey size, nesting habitat characteristics or breeding time. since data were gathered by using nest boxes, some results may be not relevant in cases of studying birds in natural holes due to differences in, for instance, predation pressure. Moreover, pressures may be also different depending on whether the bird breeds in a nest box or in a natural hole.
Datos académicos de la tesis doctoral «Feeding and breeding ecology of three insectivorous birds in mediterranean ecosystems«
- Título de la tesis: Feeding and breeding ecology of three insectivorous birds in mediterranean ecosystems
- Autor: Francisco Atienzar Navarro
- Universidad: Universitat de valéncia (estudi general)
- Fecha de lectura de la tesis: 21/12/2009
Dirección y tribunal
- Director de la tesis
- Emilio Barba Campos
- Tribunal
- Presidente del tribunal: Juan josé Sanz cid
- Francisco Valera hernandez (vocal)
- paulo a. m. Marques (vocal)
- José Verdejo bravo (vocal)