Reproductive success of polygynous male corn buntings (Miliaria calandra) as confirmed by DNA fingerprinting

Despite a sex ratio approximating to unity, female corn buntingswere not equally distributed among males. In 1989 and 1990,41.2% of 50 males were monogamously paired, 29.4% were polygynous,and 23.5% were unpaired. Polygynous males usually paired withtwo females, although in 1990 three males were trigamous. Polygynousmales fledged more offspring from their territories than didmonogamous males, mainly because they had more mates. The fledgingsuccess per nesting female was slightly higher in territoriesof polygynous males, but not significantly so. DNA fingerprintingwas used to confirm the true paternity of 44 offspring from15 broods and the true maternity of 50 offspring from 16 broods.A further 12 offspring from three broods for which neither putativeparent was available were also fingerprinted. Actual reproductivesuccess of parents was close to that inferred from observationsof number of young raised. There was only one brood, containingtwo chicks (4.5% of offspring, or in 6.7% of broods), wherethe chicks were not fathered by the male defending the territory.However, this nest was close to the territory boundary, andthe defending male may have been assigned incorrectly. Therewere no cases of intraspecific brood parasitism (n = 16 broods).The copulation rate was low, and extrapair copulation attemptswere rare, probably because of the poor chances of sneakingonto a neighbor's territory undetected and the costs of leavinga territory unguarded.