Response by waterfowl and blackbirds to an experimentally manipulated cattail marsh / Henry R. Murkin

The response of waterfowl and blackbirds to varying levels of cover removal (30%, 50%, 70%) in an overgrown cattail marsh was determined from 28 April to 9 June 1978. Cattail was removed by cutting with a discer below the water surface. Invertebrates were also monitored to determine their effect on waterfowl and blackbirds use. Invertebrate response was not different between cover levels. Dabbling duck pair use increased with increased invertebrate levels. The 50% removal plots were associated with the highest density of waterfowl pairs at any point in time. Mallard (Anas platyrhynchos) nesting was highest on the 50% and 70% removal plots. Red-winged blackbirds (Agelaius phoeniceus) used the 50% removal plots most frequently for nesting. This study provides further evidence that the potential for avian production is highest during the hemi-marsh stage of the marsh cycle. The cover removal technique was found to be most effective at controlling cattail in areas where the water depth wa