top of page
flofemale.jpg

PHOTOGRAPHIC GUIDE TO SNOWY OWL CHICKS

DEVELOPMENTAL COMPARISONS & PREDICTING THE SEX OF CHICKS

Below, the crew documented side-by-side head-on comparisons of chick development throughout stages 3-7, as well as primary wing development comparisons.

All 6 chicks were sexed using methods outlined in the publication titled 'Sexing Young Snowy Owls' (Seidensticker et al. 2011), described below.

noun-snowy-owl-5232362.png

Chick Development

IN THIS SECTION

noun-feather-10683.png

Primary Feathers

noun-binoculars-332138.png

Sexing Chicks

noun-book-1085136.png

Links & Citations

Side-by-side comparisons of chick growth & plumage for stages 3 - 7

Chick Development

Chick Development

STAGE 3

Chick 05  Est. 14 days old.jpeg
Chick 06  Est. 11 days old .jpeg

11 DAYS OLD

Chick 06

14 DAYS OLD

Chick 05

STAGE 4

Chick 01, 20 days.jpeg
Chick 03, 18 days.jpeg

18 DAYS OLD

Chick 03

20 DAYS OLD

Chick 01

STAGE 5

Chick 06, 27 days.JPG
Chick 01, 22 days.jpeg

22 DAYS OLD

Chick 01

27 DAYS OLD

Chick 06

STAGE 6

Chick 01, 35 days.JPG
Chick 06, 30 days.JPG

30 DAYS OLD

Chick 06

35 DAYS OLD

Chick 01

STAGE 7

Chick 02, 39 days.JPG
Chick 01, 38 days.jpg

38 DAYS OLD

Chick 01

39 DAYS OLD

Chick 02

Primary Feathers

In the following photos, the team documented primary flight feather growth, from quill emergence in stage 3 to fully grown flight feathers in stage 6

stage 3.jpg

STAGE 3: days 8 - 14 
Primary flight feather quills have begun to emerge in pin

stage 4.jpg

STAGE 4: days 15 - 21
Primary flight feathers have begun to erupt from their sheaths

stage 5.jpg

STAGE 5: days 22 - 28
Primary flight feathers have erupted from their sheaths

Stage 6.jpg

STAGE 6: days 29 - 35
Primary flight feathers are nearly fully grown in

Primary Feathers

PREDICTING THE SEX OF CHICKS

The crew was able to predict the sex of the six chicks: Chicks 01, 02, and 03 were sexed as males, and Chicks 04, 05, and 06 were sexed as females.

Sex is predicted based on plumage. The primary flight feathers of females are more heavily marked and characterized by dark bars that touch the rachis (feather shaft near the center of the feather), whereas the primary flight feathers of males are characterized by dark spots that do not touch the rachis, and are less heavily marked and more white in appearance. Additionally, female Snowy Owl chicks have a sooty gray body plumage while males are light gray. These methods can be used to predict the sex of Snowy Owls through their first winter.

Sexing Chicks

BELOW, the chicks on the left are males and the chicks on the right are females. Note the darker sooty body plumage of the females vs the males.

MALE.JPG
FEMALE (1).JPG
MALE (1).JPG
FEMALE.JPG

BELOW, the wing spreads on the left are males and the wing spreads on the right are females. Note the white, spotted primary feathers of the males and the dark, heavily barred primaries of the females.

MALE_ Chick 01, 35 days.JPG
MALE_ Chick 02, 36 days.JPG
MALE_ Chick 03, 37.JPG
FEMALE_ Chick 06, 30 days.JPG
FEMALE_ Chick 05, 33 days.JPG
FEMALE_ Chick 05, 30 days.JPG
Links & Citations
IMG_8251.jpg

Chloe Hernandez (left), Denver Holt (center), and Solai Le Fay (right) in Utqiaġvik, Alaska in July 2022

Citations

Holt, D.W., K. Gray, M.T. Maples and M.A. Korte. 2016. Mass growth rates and plumage development, and related behaviors of Snowy Owl (Bubo scandiacus) chicks. Journal of Raptor Research. 50: (2).

Seidensticker, M.T., D.W. Holt, J. Deteinne, S. Talbot, and K. Gray. 2011. Sexing Young Snowy Owls. Journal of Raptor Research 45: 281-289.

Recommended Citation

Le Fay S. S., Hernandez C. Y., and Holt D. W. 2023. A PHOTOGRAPHIC GUIDE TO AGING AND SEXING SNOWY OWLS FROM HATCHING TO FLEDGING. Owl Research Institute, Special Publication Number 1, Charlo, Montana, USA.

Photographic Guide to Snowy Owl Chicks

Denver W. Holt. 2022. Why Are Snowy Owls White and Why Have They Evolved Distinct Sexual Color Dimorphism? A Review of Questions and Hypotheses. Journal of Raptor Research 56(4), 440-454

bottom of page