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birds reported by Brooking (1934- 1944). In revising the Nebraska records, <br />Allen made his decisions primarily on the basis of numbers: i . e. , he accepted <br />sightings that were numerically within reason and rejected sightings that <br />involved too many whooping cranes for the years in question. However, in doing <br />so, Allen at times accepted and at other times rejected sightings by the same <br />Individuals--in effect, alternately endorsing and refuting their rel iabil ity as <br />i denti f iers. Consequently, the integrity of the pre-1950's Nebraska records, <br />as revised by Allen, is impaired with remaining uncertainty. <br />Confirmed Sigh -i nas (Section 3.2) : Because of identification probl ens asso- <br />ciated with the early sightings data, more stringent criteria for confirming <br />whooping crane sightings; along the flyway were developed by the Whooping Crane <br />Recovery Team in 1978. In accordance with these criteria, a sighting is <br />presently listed as confirmed only if the birds are observed by a State or <br />Federal biologist or officer, or other known qualified observer. Addi ti onal1y, <br />all published and unpublished records since 1940 have been reviewed for <br />authenticity by the Team.. Whooping crane sightings meeting the necessary <br />criteria are included on the Team's Confirmed Sightings List which is updated <br />following each migration season. Pre -1940 records have not been included on <br />this 1 ist because of difficulty in determining their authenticity. <br />The current version of the Confirmed Sightings List includes 14 sightings of at <br />least 39 whooping cranes recorded on or near (within 1 mile of) the Platte <br />River over the 45 -year period 1940 -1984; the number of birds was not specified <br />for one sighting. Some of these sightings were of migrants flying over the <br />river, but because the migration route of most whooping cranes in the Wood <br />Buffalo-Aransas flock takes them across the Platte River during both seasonal <br />migrations, only those sightings of birds actually observed on the river <br />_._ provide conclusive documentation of stopover use. In this regard, 8 confirmed <br />sightings involving 24 whooping cranes were actually observed on the Platte <br />River from 1940 -1984, which represent 9 percent of the total sightings and 9 <br />percent of the total whooping cranes reported in Nebraska during this time. <br />The 24 whooping cranes observed on the river over this 45 -year period <br />corresponds to an average sighting frequency of about 1 bird every 2 years. <br />Given that the flock size during migration averages approximately 3 birds, this <br />sighting frequency is perhaps better expressed as one sighting of 3 birds every <br />5 to 6 years. <br />Sighting Trends (Section 3.3) : Disregarding the problematic nature of the <br />pre-1950's data base, a full tally of past to present whooping crane sightings <br />on or near the Platte River was compiled by adding appropriate 1940 -1984 <br />records from the Confirmed Sightings List to the 1912 -1948 records accepted by <br />Al l en. Th i s compi 1 ed 1 1st i ncl udes a total of 43 si ghti ngs i nvol vi ng at 1 east <br />158 whooping cranes observed on or near the Pl atte River over the enti re period <br />from 1912 -1984 (the number of birds was not specified for two sightings). Of <br />these, 34 sightings (79 percent) involving no fewer than 127 whooping cranes <br />( 80 percent) were observed w ith in the 54 -mil a reach of the Pl atte River f ran <br />Lexington, Nebraska to about 20 miles east of Kearney designated by the Service <br />as critical habitat on May 15, 1978. <br />v <br />