Utilització de caixes niu per la Mallerenga Petita (Parus ater): comparació amb cavitats naturals
- Autores: Lluís Brotons Alabau
- Localización: Butlletí del Grup Català d'Anellament, ISSN 1130-2070, Vol. 16, Nº. 1, 1999, págs. 9-15
- Idioma: catalán
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Resumen
The Coal Tit is a cavity nester which is known to utilise nest-boxes for breeding. In a subalpine forest located in the Cadi-Moixeró Natural Park (eastern Pyrenees), I collected data on the use of nestboxes by the Coal Tit over three years and cornpared thern with the part of the population using natural cavities, with the airn of identifying differences in nest-site use by individuals. Nest-box occupancy was very low. Nest-boxes were occupied by young birds rnore frequently than expected frorn the data obtained on naturalcavity nests. The proportion of first-breeding birds in the population estirnated frorn nest-box data seerned biased in favour of young fernales as cornpared with that expected frorn the occupancy rate in natural cavities. During the first years after nest-box placernent, use of nest-boxes was biased towards juveniles; this rnay be explained by the characteristics of the urea, which contains a large proportion of natural cavities, and the propensity of individuals to nest in the sarne type of nest location in consecutive years. Our results suggest that the use of population data obtained frorn nestbox surveys rnay in certain conditions be subject to significant biases that should be taken into account in future study designs
