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25 <br />various private and public land ownerships. Studies have been underway to determine the <br />amount and effect of disturbance in wintering areas (Lewis and Slack 1992). <br />In the winter of 1985 -86, Mabie et al. (1989) examined the response of four whooping <br />crane family groups on Matagorda Island to several staged hunting and boating activities. <br />The study examined the behavior of whoopers during two hour intervals which involved a <br />staged disturbance (hunter in outboard, hunter in airboat, or airboat harassment) during the <br />first hour. Direct harassment by airboat caused the only significant difference in behavior <br />pattern (percent of time alert) when compared to control observations. Individual family <br />group responses varied greatly, with cranes responding to disturbances at distances ranging <br />from 25 to 550 m. Whooper response ranged from alert posture to walking away to flying <br />away to a maximum distance of 2,150 m. Whooping crane response was generally <br />short-term, with a return to normal behavior patterns by the second hour of observation. <br />Irby (1990) observed whooping cranes on Welder Flats for 365 hours during 1990, using <br />scan sampling and focal bird sampling techniques, and noted all events during that period <br />which caused disturbance to whooping cranes. He noted seven disturbances related to <br />hunters, which totalled 18.75 minutes in duration (alert or response behavior). Crane <br />response included: flight (4 instances), walking away (1), and alert posture (2). Irby noted <br />six disturbances related to fishing, totalling 5 minutes in duration. Crane response included <br />flight and walking (1) and alert posture (1). Commercial boats caused five disturbances, <br />totaling 11 minutes. Responses included walking away and flight (1), walking away (1), <br />and walking away and returning (3). Of the 365 hours of observation, cranes spent 47 <br />minutes responding to non - observer human - induced disturbance. <br />Irby (1990) made several recommendations resulting from his observations. Barge mooring <br />may represent a dangerous threat. A coordinated plan needs to be developed to protect the <br />area from pollution, and to designate safe barge mooring areas. Refuge and coastal wetland <br />users should be encouraged to minimize disturbance to whoopers. Boaters should be <br />educated about damage caused to submerged vegetation by boating activities. The support <br />of the private landowner in minimizing disturbance and maximizing protection should be <br />recognized and encouraged. <br />It is difficult to assess the total impacts of disturbance upon whooping cranes in terms of <br />fitness, productivity, and survival. Some birds habituate to boat activity (Stalmaster and <br />Newman 1978, Knight and Knight 1984). As the AWP continues to expand, a decrease in <br />territory sizes and expansion into new wintering areas is likely to continue. Any increase in <br />frequency or severity of disturbance could be compounded by the effects of increased <br />population density and /or exposure to the disturbances. Levels of disturbance should be <br />monitored on the wintering grounds and steps taken to minimize detrimental activities. <br />Two graduate students from Texas A and M are studying whooping crane winter foods <br />under the direction of Dr. Doug Slack. Felipe Chavez - Ramirez started in September 1992 an <br />investigation of the standing crop biomass of blue crabs, clams, and wolf berry berries and <br />evaluating human and wildlife competition for these principal crane foods. In 1993, Jay <br />Nelson initiated a study to determine the nutritive composition of the winter foods and <br />compare that to the commercial rations used for the captive flocks. <br />