ABSTRACT
Miners are sexually monomorphic; the sex ratio may be as skewed as 3.5 males per female. Because of this complex social behavior and the different spacing patterns shown by males and females, expression of density in terms of pairs per hectare is not only irrelevant, but misleading. It is thus better to express density in number of birds per hectare. This method is appropriate for use in colonies with moderate to dense populations. After patrolling the area of interest, determine the ratio of sightings of banded to unbanded birds, tally the number of different banded birds, and apply the recapture-ratio method. This method is particularly suitable in areas of sparse vegetation and good visibility. This suggests that estimate of group size in the former method is accurate. To minimize the effect of this variation on estimates of density, the observer Generally, a miner flies short distances.
