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I <br />this season, thus resulting in more sighting opportunities than in the spring <br />(FWS 1982a, p. 1). <br />Interestingly, Allen (1952, p. 102) noted fewer reports of fall migrants based <br />on his review of sighting records through 1948. He suggested that this may <br />reflect waning enthusiasm among bird watchers after the period of peak interest <br />in the spri ng. On the other hand, Allen commented that many fall sightings, <br />especially in Nebraska, were contributed by hunters. <br />The flock sizes of migrating whooping cranes observed in Nebraska reflect <br />trends similar to those reported for the flyway as a whole. Of the 89 con- <br />firmed sightings reported for Nebraska f ran 1940 -1984 (FWS 1985) , 87 sightings <br />specify the number of birds seen. Based on these records, the number of birds <br />per si ghti ng ranged f ran 1 to 9 and averaged 3.1. Flock sizes of 2 and 3 birds <br />(accounting for 31 and 29 percent of the sightings, respectively) were observed <br />most frequently (Figure 2 -3); 72 percent of the sightings were of 3 birds or <br />less.. and 92 percent were of 5 birds or 1 ess. Among the 89 confirmed sightings <br />for the state, 37 (42 percent) were reported in the spring and 50 (56 percent) <br />were reported in the fall reflecting less variation between seasons than noted <br />by the Service for the migration corridor overall. The remaining two sightings <br />for the state were those of an apparent summer wanderer(s) observed during the <br />late spring and summer of 1950 (see Section 2.2) . The average number of birds <br />per sighting in Nebraska during spring (3.2) and fall (3.1) reflect similar <br />flock sizes during both migration seasons. <br />2.4 FLIGHT DISTANCES <br />Although whooping cranes are primarily diurnal flyers, several flights recorded <br />during the radio - tracking program in fall 1982 originated before daybreak and <br />continued after nightfall (FWS 1982b, pp. 1 -4) . Daily flight distances reflect <br />considerable variation.. and are likely influenced by fatigue, hunger, weather, <br />and other factors. Migrating birds are capable of making long, sustained <br />fl ights when weather and wind conditions are favorable. However, they tend to <br />curtail their fl ights or extend their stopovers when strenuous and /or hazardous <br />fl ight conditions are encountered (e.g. , storms, fog, or strong headw Inds) . <br />During the initial radio - tracking effort in fall 1981, the distances flown by a <br />family of whooping cranes migrating toward Aransas NWR ranged f ran 1 to 290 <br />miles (FWS 1981b, p. 10) . In subsequent years, substantially longer fl ights <br />were documented during radio-tracking surveys. A family of whooping cranes <br />tracked in fall 1982, for example, flew a total of 949 miles in less than 48 <br />hours (FWS 1982b, p. 4) . Following their departure from a small pond in the <br />Nebraska Sandhil l s (about 15 miles southeast of Ainsworth) the birds covered <br />504 miles in a single fl ight, arriving after sunset to roost in a shallow bay <br />on Fort Cobb reservoir approximately 15 miles northeast of Anadarko, Oklahoma. <br />They left the reservoir at about 0900 the next morning and flew another 445 <br />miles before setting down after dark in a shallow marsh located on a ranch <br />about 5 miles northwest of Vindaurri, Texas some 28 miles west of Aransas NWR. <br />Similarly, another whooping crane family monitored during fall 1983 traveled a <br />distance of approximately 1,140 miles (from near Pierre, South Dakota to <br />Aransas NWR) in 2 days (FWS 1984a, p. 1) . <br />2 -5 <br />