High inbreeding was expected in a very small, apparently isolated colony of llie monogamous passerine Bearded Tit (Panurus biarmicusL.) where it had been shown that juveniles, prior lo the summer molt, form permanent pairs, some of which breed the following year in the study area. Since very early pairing, prior to the dispersal of sibs, might occur between sibs (unless prevented by some mechanism of kin recognition and discrimination), we traced the movements of six sets of sibships for 45 days post-fledging and observed whether any of the birds would pair within this time. Sibs did not disperse more than a few hundred metres from their nests, and tended lo congregate in a preferred area. Four pairs (one between sibs) formed during this period. Contrary to expectation the fingerprints of 13 random adults showed a very low similarity index, typical of large, outbreeding populations. Possible explanations of this unexpected result are considered.