Snowy owls are large white owls that inhabit the Arctic regions of North America and Eurasia. They are known for their bright white plumage that helps them camouflage into the snowy tundra environment. Snowy owls go through predictable plumage changes throughout their lives that are related to age, season, and breeding condition.
Do snowy owls molt and change feathers?
Yes, like all birds, snowy owls molt and replace their feathers periodically. Molting is the process where old worn feathers are replaced by new feathers. Snowy owls have a complex molting cycle and molt throughout the year. However, their main molting periods are late summer to fall and late winter to spring.
Snowy owl feathers become worn and damaged over time from exposure to the elements and everyday wear and tear. Molting allows them to regrow fresh new feathers to maintain their insulating and flight capabilities. It also enables them to change their plumage coloring as they age.
Juvenile snowy owl molting
Juvenile snowy owls have distinctive plumage that differs from adult birds. Hatchlings start out covered in white down. At around 3-4 weeks old, their juvenile feathers start growing in. Juveniles have plumage with brown scalloping over much of the body, wings, and head.
Within the first fall and winter, juveniles go through their first complete molt. Their new feathers replace the juvenile plumage with nearly pure white coloring. By their second winter, juveniles are difficult to distinguish from adult snowy owls.
Adult snowy owl molting
Adult snowy owls molt all their flight feathers once a year after breeding. This yearly complete wing molt leaves them unable to fly for up to 3-4 weeks. During this time they are vulnerable to predators and food shortages.
Adults may also go through partial molts of body feathers during the year. Replacing a few feathers at a time reduces molting stress and allows them to maintain flight.
Do male and female snowy owls have different plumages?
Male and female snowy owls have very similar plumage. They are predominantly white overall with variable black barring. Females tend to have more and heavier markings compared to males.
During the breeding season, the only noticeable plumage difference between mature males and females is that males can have nearly pure white underparts while females retain dark barring. However, these differences are subtle and males and females remain practically indistinguishable by plumage alone.
Female snowy owl plumage
Female snowy owls tend to have more extensive dusky spotting and barring across the body and wings compared to males. The head usually has some dark streaking. The underparts can range from heavily marked with dusky barring to mostly white.
Male snowy owl plumage
Males typically have fewer dark markings than females. The head and breast are often nearly solid white with little to no streaking or spotting. The rest of the body and wings have variable dark barring. Males can occasionally be almost pure white overall.
Do snowy owls change color with age?
Yes, snowy owls go through age-related plumage changes throughout their lives:
Juvenile snowy owl plumage
- Brown scalloped upperparts
- Heavily barred underparts
- Dark tail with white bands
Immature snowy owl plumage
- Mostly white plumage
- Some retained juvenile feathers
- Dark spots and streaks on head and body
Adult snowy owl plumage
- Pure white plumage
- Variable dark barring and spotting
- Females have more markings than males
Aged adult snowy owl plumage
- Plumage discolored and stained
- Feathers become ragged
Do snowy owls change plumage seasonally?
Snowy owls do not dramatically alter their plumage between seasons. However, some subtle seasonal differences may occur:
Winter plumage
- Whiter plumage overall
- Reduced dark spotting and barring
Summer plumage
- Slightly more dusky markings
- Small increase in dark spotting and streaks
These changes are due to feather replacement during molting periods. More feathers are replaced in winter leading to whiter plumage. In summer, higher hormone levels can cause more melanin production leading to increased dark patterning.
Do breeding snowy owls change color?
Snowy owls do not undergo dramatic coloring changes for breeding. However, some subtle plumage differences may occur between breeding and non-breeding seasons:
Non-breeding plumage
- Males and females can not be distinguished by plumage
- Both sexes spotted and barred white and dusky brown
Breeding plumage
- Males have whiter underparts with less barring
- Females retain more underpart barring
- Females can exhibit darker spotting overall
These minor changes are influenced by hormonal shifts. Higher sex hormone levels during breeding can lead to reduced melanin in males and increased melanin in females.
Do snowy owl chicks change color?
Yes, snowy owl chicks go through dramatic plumage changes in their first year of life:
Nestling owlets
- Covered in white down
Fledgling juveniles
- Scalloped brown upperparts
- Heavily barred underparts
- Barred tail
Immature owls
- Mostly white plumage
- Retains some juvenile feathers
These age-related color changes provide camouflage appropriate to each stage of development. The brown juvenile plumage helps fledglings blend into the tundra environment while they learn to hunt.
Conclusion
In summary, snowy owls do undergo plumage changes throughout their lives. Molting enables them to replace worn feathers with fresh plumage. Juveniles transition from brown to mostly white. Adults can become whiter in winter. Minor variations occur between sexes and breeding/non-breeding seasons. However, snowy owls do not have dramatically different seasonal plumages like other owl species. Their white coloration provides year-round camouflage in the open Arctic.