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i,.. <br />f: <br />itsel f, 1 ittl e topographic rel ief (usually less than 30 -40 <br />ft., often less than 5 -10 ft.) and gradual slopes (usually <br />less than 7 -90; often less than 4-50).11 <br />Information gathered during radio - tracking surveys further supports the <br />fl exi bit ity of the whoopi ng crane s di et duri ng migrati on. Accounts of the <br />fall 1981 tracking effort (FWS 1981b, pp. 1 -10; Williams 1981) noted that the <br />monitored family fed on grain in Saskatchewan and Kansas; insects and earth- <br />worms beneath cow chips in Nebraska; grasshoppers, tadpoles, crayfish, and <br />newly planted winter wheat in Oklahoma; and sorghum fields in Texas. In <br />general, however, grain fields were dominant among the selected feeding sites <br />along the southern two-thirds of the migration route (FWS 1981b, p. 10) . <br />During the fall 1982 tracking survey, monitored birds were observed feeding in <br />barl ey and wheat fiel ds, as wel l as wetl ands al ong a 1 ake shore i n Saskat- <br />chewan, and on small (4 -inch) fish in a shallow embayment of Fort Cobb <br />Reservoir near Anadarko, Oklahoma (FWS 1982b, pp. 1 -4) . At this latter site, <br />two adul t whoopi ng cranes were observed feedi ng thei r young offspri ng at the <br />rate of 16 fish per minute, or nearly one fish every 4 seconds. <br />As consistent with observations elsewhere along the flyway, confirmed sightings <br />of whooping cranes along the Matte River in Nebraska reflect prominent use of <br />adjacent agricultural lands as feeding sites (FWS 1981a, p. 38). For exam pl e, <br />five birds that roosted in the river during the night of October 21 -22, 1966 <br />were seen in a wheat field about 5 miles from the river the next morning. <br />Similarly, two adults sighted during October 31- November 1, 1974 were observed <br />probing in the shallow waters of the river and, on at least one occasion, <br />feeding in a cornfield on the south side of the river. A pai r of whooping <br />cranes reported in the spring of 1980 (April 17 -18) were first observed feeding <br />in a recently di sced cornfield 2 to 3 miles from the river. They subsequently <br />flew to the river where they loafed for about 25 minutes before moving to a <br />plowed cornfield 1 mile south of the river. A short time later they relocated <br />to the National Audubon Society's Lillian Annette Rowe Sanctuary where they <br />were observed foraging in a recently burned pasture. The next morning, after <br />apparently roosting in the river, the pair was briefly observed loafing, <br />preening, dancing, and probing in the shallow water of the river before leaving <br />the area (FWS 1981a, p. 38). <br />Migrating whooping cranes are also quite fl exi bl e in their selection of roost <br />sites along the flyway. Johnson and Temple (1980, p. 45) stated that the <br />selection of roosts is probably affected by: (1) time of day; (2) the <br />distribution and abundance of potential roost sites; (3) weather conditions; <br />(4) physiological factors (e.g., hunger, fatigue, or injury); and (5) possibly <br />the presence of other cranes which may attract the birds. They commented that <br />migrant whooping cranes will use whatever suitable roosts are avail able when <br />one or a combination of these factors influence the birds to look for a place <br />to land. <br />Based on an evaluation of 64 roost sites, Johnson and Temple (1980, pp. 37 -38) <br />identif ied 13 different types of roosti ng habi tat used by migrati ng whoopi ng <br />2 -12 <br />