. The Canadian field-naturalist. 296 The Canadian Field-Naturalist Vol. 92. Figure 2. Osprey nest on utility pole, Antigonish County, Nova Scotia, 1976. nearly full-grown young fledged nonetheless. Three young from a nest toppled by wood cutters in 1975 (21 July) presumably died. In 1976, one active nest was destroyed by a forest fire that burned several thousand acres of potential nesting habitat. During 1976, seven nests were abandoned at various stages of incubation, one after 60 d. Henny and Wight (1969) suggested that a recruitment of between and young per active nest was needed
. The Canadian field-naturalist. 296 The Canadian Field-Naturalist Vol. 92. Figure 2. Osprey nest on utility pole, Antigonish County, Nova Scotia, 1976. nearly full-grown young fledged nonetheless. Three young from a nest toppled by wood cutters in 1975 (21 July) presumably died. In 1976, one active nest was destroyed by a forest fire that burned several thousand acres of potential nesting habitat. During 1976, seven nests were abandoned at various stages of incubation, one after 60 d. Henny and Wight (1969) suggested that a recruitment of between and young per active nest was needed to maintain a stable population. Postupalsky (1974) urged that estimates of Osprey production be based on all occupied nests. Our results are based on occupied nests since we could not be sure whether eggs had been laid and later disappeared. The average productivity on utility poles and natural nest sites was and respectively. Limiting Factors In July anadromous fish in the rivers became less available, and the Ospreys shifted their hunting to coastal estuaries, where Winter Flounder {Pseudo- pleuronectes americanus) became the main food Table 1—Reproductive success of ospreys in Antigonish County, Nova Scotia, on utility poles and natural sites' Nests found Occupied nests Active nests Productive nests Young raised Young occupied nest (known outcome) 1975 Utility poles Natural sites Total 19762 Utility poles Natural sites Total Total 15 7 22 12 7 19 12 6 18 5 5 10 13 9 22 14 (17) 8 ( 9) 22 (26) 14 (17) 8 ( 9) 22 (26) 12 (15) V ( 8) 20 (24) 9 (10) 2 ( 3) 11 (13) 19 (22) 6 ( 7)3 25 (29)3 () .86 ( .88)3 ()3 44 (48) 41 (45) 38 (42) 21 (23) 47 (51)3 ()3 'Terminology follows that of Postupalsky (1974), but with slight modifications. An occupied nest was a nest attended by two birds early in the season. An active nest was an occupied nest in which eggs were seen or from which the female did not flush during the first survey. A pr
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