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~-~.... 31 Table 3, Size and productivity of the whooping crane captive flock at PWRC, 1975-1993, Eoos retained at PWRC All Females Total Chicks Year Birds Laying Eggs. No. Fertile Hatched Fledged 1975 20 1 3 3 2 1 0 1976 19 2 5 3 1 1 1 1977 21 4 22 8 4 3 2 1978b 22 3 23 8 8 7 3 1979" 26 4 21 16 10 8 4 1980 22 2 6 4 1 0 0 1981 20 2 11 11 5 3 1 1982 26 5 28 15 12 9 6 1983 35 5 34 22 18 14 8 1984 32 5 31 21 16 12 4 1985 38 3 13 13 8 7 6 1986d 38 0 0 1987 41 5 7 7 3 2 1 1988 46 6 15 15 8 7 3 1989 32 5 19 19 14 9 8 1990 35 4 14 14 5 4 3 1991 40 5 21 21 9 5 2 1992 49 8 48 48. 11 9 8 1993 49 8 35 35 16 15 10 Totals 611 77 356 283 151 116 70 a Includes 73 eggs transferred to Grays Lake National Wildlife Refuge in 1976-1984. Fertility determined for unhatched eggs by examination of egg contents, Examination occurred after full-term incubation and eggs containing no detectable embryo were considered infertile, therefore, the number of fertile eggs listed is considered a minimum estimate, b All eggs retained at PWRC were incubated and hatched under sandhill cranes and chicks were "foster-parent" reared. All eggs transferred to GL were artificially incubated until transfer, c All eggs retained at PWRC were incubated under sandhill cranes and chicks were hand-raised or foster-parent raised by sandhill cranes. All eggs transferred to GL were incubated under captive pairs of sandhill cranes at Patuxent until transfer this year and subsequent years, . d No eggs were produced in 1986. Breeding birds were moved temporarily to pens in Summer 1985 during construction of new pens. The birds were moved into the new pens in November 1985. These movements were believed to be the disturbance that disrupted the 1986 breeding cycle. e Six new pairs broke the eggs (19) they produced.