MaleTabanus nigrovittatusMacquart hover as a premating strategy in the early morning over Atlantic coastal salt marshes. These males are distributed with peak densities near mosquito ditches and with fewer hovering males farther from the ditch. Multivariate analysis indicated that male density or the distance between individuals is an important factor in structuring hovering male spatial distribution. When compared with previously published data, male densities match peak emergence of females.T. nigrovittatusnumbers are lowest directly adjacent to mosquito ditches, whereTabanus conterminus(Walker) tends to hover, suggesting that spatial separation may contribute to reproductive isolation in these two sibling species.