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Providing evidence to improve practice

Individual study: Roost harassment as an alternative to lethal control is only temporarily effective in reducing double-crested cormorant Phalacrocorax auritus predation at catfish farms in the Mississippi delta, Mississippi, USA

Published source details

Tobin M.E., King D.T., Dorr B.S., Werner S.J. & Reinhold D.S. (2002) Effect of roost harassment on cormorant movements and roosting in the delta region of Mississippi. Waterbirds, 25, 44-51

This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Disturb birds at roosts Bird Conservation

A replicated, controlled study in 1997 near channel catfish Ictalurus punctatus ponds in the Mississippi delta, USA (Tobin et al. 2002), found that harassed double-crested cormorants Phalacrocorax auritus flew farther to their next roost than birds not harassed the previous night. Only 11% of harassed birds returned to the same roost within 48 hours, compared with 81% return to non-harassed roosts. Harassment shifted birds away from areas of catfish farm concentrations, but effects were temporary. Farmers undertook co-ordinated night-roost harassment patrols and prior to patrols, 50 cormorants were radio-tagged and their movements monitored from January through March 1997.