not survive their first year, in comparison to adult female annual mortality which was estimated at 10.5%. Similarly, in southern Finland, from 29 to 58 breeding pairs bred annually in the same study area and could produce anywhere from 1.17 to 3.21 fledglings depending on prey cycles (3.5 average fledglings per successful attempts in high vole years against 1.79 per successful nest in low vole year). Finnish study showed that 21.7% of all clutches failed to hatch and 4.3% died completely after hatching.Saurola, P., & Francis, C. (2018). Towards integrated population monitoring based on the fieldwork of volunteer ringers: productivity, survival and population change of Tawny Owls Strix aluco and Ural Owls Strix uralensis in Finland. Bird Study, 65(sup1), S63-S76. Hatchability in south Finland averages 87% across all years. On a broader scale, from 422-1710 territories were recorded in Finland from 2009-2011 with the number of successful nests ranging annually from 168 to 1341. The population trends were more or less mirrored by those of the Finnish tawny owls but tawny brood size averages 0.68 larger than that of the Ural. Prospects for breeding are generally low during the low point of the three year cycle of the vole prey of Urals in south Finland but paradoxically when a high vole year is followed by a low one, the number of attempted clutches is higher but the rate of nest failure is higher. For instance, within a Finnish study, 144 eggs were found in 63 nests during a low vole phase, in the increase phase 1212 from 338 nests and in peak phase 1259 eggs from 345 nests. However, this study showed low recruitment from clutches was detected in both increase and peak years, and the complications and individual variations of each pair may cause variations that the previous theories do not account for. Breeding success in southern Finland was also driven by the mother Ural owl’s age, with 3-5 year old females being less productive than those that were 6 to 9 years old, and that older females, of more than 10 years old, tended to lay larger and more rounded eggs. In Finland, supplemental fed pairs nest up to 1 week earlier and produce up to 0.6 more eggs than those that were not, therefore food limitation does appear to effect productivity of the species. Males were mildly more numerous in Finland among fledged young (56%) but survivorship