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<br />and are characterized by oak brush, grassland, swales, and ponds. Typical plants include
<br />,
<br />live oak (¢uercus vir iniana), redbay (Pars a bo 'rboni a and bluestem (Andropogon spp.)
<br />(Stevenson and Griffith 1946, Allen 1952, Labuda and Butts 1979). During the last 20
<br />years, many upland sites have been grazed, mowed, and control burned ( Labuda and Butts
<br />1979). The refuge maintains as many as 3300 ha of grassland for cranes, waterfowl, and
<br />other wildlife. Human visitation is carefully controlled, and other potentially conflicting uses
<br />of the refuge, such as activities associated with oil prd gas exploration and pumping
<br />operations, are reduced when whooping
<br />As noted previously, critical habitat was designated for whooping cranes in 1978. Critical
<br />habitat is defined within the Endangered Species Act as habitat which contains those
<br />physical or biological features, essential to the conservation of the species, which may
<br />require special management considerations or protection. Critical habitat was identified for
<br />nine sites in six states (W. Re[. Vol. 43, Number 94, May 15). The interested reader is
<br />referred to the Federal R for a detailed description of the sites. However,
<br />these sites
<br />are: (1) Monte Vista NWR, Colorado;
<br />(2) Alamosa NWR, Colorado; (3) Grays Lake NWR and
<br />vicinity, Idaho; (4) Cheyenne Bottoms State Waterfowl Management Area, Kansas; (6) the
<br />Platte River bottoms between Lexington and Dehman, Nebraska; (7) Bosque del Apache
<br />NWR, New Mexico; (8) Salt Plains NWR, Oklahoma; and (9) Aransas NWR and vicinity,
<br />Texas.
<br />D. Life History
<br />Wild whooping cranes were not individually marked until 1975 (Orewien and Bizeau 1978,
<br />Kuyt 1978, 19790; consequently, some es pacmaximumrlongevity in the wlife history and
<br />d oft22 -24 biology
<br />remain uncertain. Current estimates sugg
<br />years (Binkley and Miller 1980). Captive individuals
<br />old when he died0at San Antonio Zoo6n,1979.
<br />Moody 1931). "Crip" was at least 33 y ears
<br />"Josephine" was at least 27 years old at the time the captive flock (McNulty 19 ).1 "Ca US ",
<br />a 29- year -old male, is still reproductively active
<br />Whooping cranes are monogamous, but will remat6, sometimes within only a few weeks, shop and Blankinship
<br />following the death of their mate (Blankinship 1976,
<br />(1982) documented several instances in which twoanstancesrinlwhichr nesting pairs birds
<br />paired
<br />with unmarked birds. Kuyt (198 1-a) observed
<br />contained one member (a male in each instance) that was known to beo r Bishop ( 984)
<br />year -old female has also nested, but pair formation can be a lengthy press.
<br />observed pair bonds that developed over 1 to 3'vst ears from duc production istslightly over gd4lyea0sks
<br />on the wintering grounds. The average age of f 9g P
<br />(E. Kuyt, pers. comm. 1991).
<br />Most pairs return to the nesting area in WBNP in late April, and begin nest construction and
<br />egg laying.
<br />Experienced pairs arrive first, show considerable fidelity to their breeding
<br />territories, and normally nest e nesting a eas"1evatry'co considerably inrsi eh and range9 from
<br />territories -- termed "composite 9
<br />about 1.3 to 47.1 km2 (Kuyt 1976a, 1976b, 1981 a). From the initiation of laying until
<br />chicks
<br />are a few weeks of age, the activities of pairs and family groups are restricted to the
<br />
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