Sexual maturity reached the following year but the first breeding is normally at no sooner than the end of the second year of life.
There is little strong evidence of typical age of first breeding but initial breeding by males could be inferred by the plumage of males in Barrow by plumage.
At that stage, which the males were essentially all pure white, most were aged to about 3 to 4 years old.
The snowy owl seems to markedly inconsistent in regard to breeding every year, often taking at least up to two years between attempts and sometimes as much as nearly a decade.
7 satellite-marking females in Canada proved that they did breed in consecutive years, with 1 breeding over 3 consecutive years.
In 23 years at Barrow, snowys bred in 13 of them.
Nesting success can reach 90–100% in even the largest clutches in high lemming years.
While over the course of 21 years, 260 total nests were recorded in Barrow.
There, from 4–54 nests were recorded annually.
The Barrow nests bore 3 to 10 sized-clutches with a mean of 6 eggs per nest and an annual mean hatching success from 39 to 91%.
31–87% of chicks were able to depart on foot and 48–65% were annually estimated to survive to fledge; elsewhere, 40% survived to fledge.
In another set, 97% of observed eggs both hatched and fledged.
In Norway, the fledging success from 10 nests was much lower at about 46%.
Norwegian data, which previously indicated it to be an almost accidental breeder in northern Norway, indicates that it is a more regular breeder than expected, though.
3 good years were found for snowy owls between 1968 and 2005: 1974 (when there were 12 pairs), 1978 (22 pairs) and 1985 (20 pairs), with 14 additional locations when potential (but not confirmed) breeding has occurred.
The main determinable causes of nest failure were deemed to be starvation and exposure.
A number of Norwegian and Finnish nests were known to fail due to severe black fly parasitism.
Sexual maturity reached the following year but the first breeding is normally at no sooner than the end of the second year of life. There is little strong evidence of typical age of first breeding but initial breeding by males could be inferred by the plumage of males in Barrow by plumage. At that stage, which the males were essentially all pure white, most were aged to about 3 to 4 years old. The snowy owl seems to markedly inconsistent in regard to breeding every year, often taking at least up to two years between attempts and sometimes as much as nearly a decade. 7 satellite-marking females in Canada proved that they did breed in consecutive years, with 1 breeding over 3 consecutive years. In 23 years at Barrow, snowys bred in 13 of them. Nesting success can reach 90–100% in even the largest clutches in high lemming years. While over the course of 21 years, 260 total nests were recorded in Barrow. There, from 4–54 nests were recorded annually. The Barrow nests bore 3 to 10 sized-clutches with a mean of 6 eggs per nest and an annual mean hatching success from 39 to 91%. 31–87% of chicks were able to depart on foot and 48–65% were annually estimated to survive to fledge; elsewhere, 40% survived to fledge. In another set, 97% of observed eggs both hatched and fledged. In Norway, the fledging success from 10 nests was much lower at about 46%. Norwegian data, which previously indicated it to be an almost accidental breeder in northern Norway, indicates that it is a more regular breeder than expected, though. 3 good years were found for snowy owls between 1968 and 2005: 1974 (when there were 12 pairs), 1978 (22 pairs) and 1985 (20 pairs), with 14 additional locations when potential (but not confirmed) breeding has occurred. The main determinable causes of nest failure were deemed to be starvation and exposure. A number of Norwegian and Finnish nests were known to fail due to severe black fly parasitism.
Snowy owl