El carricerín real (Acrocephalus melanopogon) en el P.N. del Prat de Cabanes-Torreblanca
This research has focused on five aspects of the biology and ecology of Moustached Warblers (Acrocephalus melanopogon) in the Cabanes-Torreblanca Natural Park. First, with respect to populaton abuaaandance, average density of this species during breeding season was 1.9 birds/ha. Average densities for other species of the community were: Reed Warbler (A. scirpaceus) 0.17 birds/ha, Great Reed Warbler (A. arundinaceus) 0.39 birds/ha, Savis Warbler (Locustella luscinioides) 0.39 birds/ha and Fan-tailed Warbler (Cisticola juncidis) 0.28 birds/ha. A comparison of the composition and structure of passerine communities of several mediterranean wetlands (Delta del Ebro, Prat de Cabanes-Torrebloanca, Albufera de Valencia, Fondó dElx y SAlbufera de Mallorca) has shown that the community of Prat is the most singular and stable, owing to the high density of A. melanopogon associated with low densities of the migrant A. scirpaceus. The monitoring of the population trend of A. melanopogon shows a decline of density between the period before and after the drought of the years 1994-95. Breeding density decreased form 4 birds/ha to 2 birds/ha while winter density decreased from 3 to 1 birds/ha. The species is present in the study area duirng the whole year. Its density increases in march and reaches a maximum early in summer, but decreases until a minimum by the end of this season. Density increases again in autumn and decreases in mid winter. The analysis of ringing recoveries has shown important differences between the four european populations with enough data available (lake Neusiedler, Camargue, Prat, SAlbufera). The population of Prat makes movementes in two opposite directions (NE and SW). Youngs of this population diseperse from may to july while adults disperse between july and september. Native birds of the Prat are recaptured in other wetlands mainly between july and november, but may remain there even until february and march. There are no differences between young and adults in the temporal distribution of captures in these wetlands. The biometrical analysis identified differences between males and females in most paremeters studied. Moreover, wing length and weight increase with age. It has been possible to develop a logistic regression model, based in the lenght of primaries 2, 3, 8 and 9, that allows the classification of most wintering individuals as being native of the Prat or coming from the french population. This model has been used to study the winter phenology of both populations. Finally, the capture-recapture data have been used to estimate apparent survival (?). This parameter has decreased along the study years, form values of about 0.7 in the period 1990-93 to values of 0.5 in 1994-2002. Survival of youngs has oscillated around 0.3. The climatic variables analyzed seem to be not related to survival fluctuations, but it is probable that this decrease of survival be one of the causes of the population decrease.
Advisor:López Iborra, Germán
School:Universitat de València
Source Type:Master's Thesis
Keywords:microbiologia i ecologia
Date of Publication:12/19/2003