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2.5 TRAVEL TINE <br />Based on five separate radio-tracking efforts conducted during the fall <br />(Appendix A), whoop! Hg cranes compl eted the 2,400 mile migrati on from Wood <br />Buffalo National Park to Aransas NWR in 27 to 32 days (29 days average). In <br />all cases, more time was expended traversing the approximately 900 -mile leg of <br />the journey through Canada, than the approximately 1,500 -mile leg across the <br />United States. Radio-tracked birds spent 18 to 23 days (20.4 days average) <br />traveling from Wood Buffalo National Park to the U.S.- Canadian border, as <br />opposed to 3 to 14 days (8.6 days average) travel ing from near the border to <br />Aransas NWR. The time spent in the Canadian versus U.S. portion of the flyway <br />supports earlier speculation by the Service (FWS 1982a, p. 1) that during the <br />fall migration whooping cranes move more slowly through Canada and then assume <br />a faster pace through the states. <br />Four radio-tracking efforts were conducted to monitor whooping cranes during <br />thei r spri ng migrati on (Appendix B) , but only two efforts were conti nued 1 ong <br />enough to track the birds all the way to Wood Buffalo National Park. In one <br />case, the monitored birds completed the entire trip in 23 days (10 days in the <br />U.S. and 13 days in the Canadian portion of the flyway); whereas the other trip <br />was completed in 14 days (12 days in the U.S. and 2 days in Canada). As noted <br />by Johnson and Temple (1980, p. 26) , some researchers have suggested the spring <br />migration is probably more rapid than in the fall because (1) the birds may <br />experience a stronger physiological stimulus to reach the breeding grounds than <br />the wintering grounds; and (2) family groups have to make more and longer stops <br />in the fall to allow sufficient time for young birds to rest and feed. <br />Though both of the complete radio-tracking surveys in the spring reflected <br />shorter travel times than observed during fall tracking efforts, the remaining <br />two (incomplete) surveys indicated that some spring migrants, particularly <br />immature birds, move north at a sl ower pace (Appendix B) . In one of these <br />latter two surveys, two yearlings traveled to northwestern Alberta, within <br />approximately 350 miles of Wood Buffalo National Park, in 38 days. In the <br />other, a family group with a young, radio-tagged bird traveled to the North <br />Battl eford, Saskatchewan area (approximately 525 miles southeast of Wood <br />Buffalo National Park) in 13 days. The adult birds remained in this area for 8 <br />days and then departed, apparently for the breeding grounds, without the young. <br />(Disassociation of adults from juvenile birds before arriving at Wood Buffalo <br />National Park is apparently typical, but the point of separation has not been <br />reported previously [Johnson and Temple 1980, p. 25.7) The young whooping <br />crane left the vicinity of Blaine Lake, east of North Battleford, some 13 to 15 <br />days later (34 to 36 days after departing from Aransas NWR) , and was subse- <br />quently observed at Wood Buffal o National Park (FWS 1984b, p. 1) . Th us, it <br />appears that young whooping cranes, lacking the reproductive urge of mature <br />birds, are 1 ikely to spend more time migrating to the breeding grounds. <br />2.6 STOPOVER DURATION <br />The majority of stopovers during both fall and spring migrations are of the <br />overnight (2 -day) type, where 'the birds arrive one day and leave the next. <br />They represent brief stops (of about 12 to 16 hours) to rest and feed. Of the <br />2 -7 <br />