A nest-box and colour-ringing study of Bearded Tits Panurus biarmicus at Leighton Moss, Lancashire

Abstract

Since 1997, Bearded Tits Panurus biarmicus have successfully nested in reed nest boxes positioned in reed Phragmites australis growing in standing water at Leighton Moss RSPB Reserve. Before nest boxes were installed, the bulk of the breeding population nested in dry reed areas but the provision of nest boxes resulted in a shift to the wetter areas of reed. Nest boxes were used mainly for early nesting attempts, with the birds moving to natural sites as cover increased for later broods. In the 18 years of the study 309 nests were monitored of which 48.5% successfully produced young. Some colour-ringed birds showed considerable movement between nesting attempts, with the average distance being 203 m. The time between fledging and the first egg of a second brood averaged 9.6 days. Pair fidelity was high, with two pairs breeding together for three years. The advantages of nest boxes included attracting pairs to nest in the area with the highest abundance of invertebrates, well above any flood level.