A Snowy Christmas 2013

_MG_4531 copyAn unprecedented number of Snowy Owls irrupted south this winter and made for some awesome opportunities to see these majestic creatures. Unfortunately since these flights are prompted by too many birds and not enough food, some were emaciated and starving and some were found dead as result. CT did well with several birds being rather photogenic. Thankfully many photographers remained respectable, though people trying to take photos of them with their smartphones continue to piss off everyone that understands that you can’t use your smartphone for bird photography unless the bird is embedded up your nostril. Really people…enough with the phone nonsense 🙂

CAM01101

Ace photographer and awesome dude AJ Hand and Alex getting to grips!

I used to think I could age and sex some Snowy Owls. While I think the heavily barred birds with boldly barred napes and minimal white “bibs” are females, and the lightly marked and almost white birds with broken tailbands are males, this isn’t always the case.

CAM01114 copy

Snowy Sunset

Birds with vermiculated inner greater coverts and primary tips may be first-years (HY) but I’m not sure older birds cannot show these in successive moults, so it really is hard to age and sex birds of unknown age in the field. Individuals often get lighter with age, stay the same, or get darker so there is a whole gamut of variation and overlap. Apparently according to Russian research, first borns in the nest are often paler than successive hatchlings which are darker! Also, some HY males (aged in the hand from banding / specimens) may overlap with adult females and may only be differentiated by size. Pyle mentions tail (?) feather shape (blunt and rounded vs bluntly pointed) as a means of ageing some birds, but this seems hardly useful in the field.

snow

_MG_4889 copy

_MG_5293

The only main way of ageing Snowy Owls to calendar year (after HY/SY) is perhaps during June-September when birds have an incomplete primary moult and it MAY be possible to differentiate between old and new primaries.

I have seen few birds in New England I would call “females. This fits the migration pattern which basically is that females, being larger and dominant, take territory further north and it is the males that are “pushed” out further south. It also makes sense, from a probability point of view, that many of these birds are likely HY birds.

So, it seems from conventional wisdom that while we may think a bird is a young bird, or most likely a female (if large and boldly barred) we are likely guessing a lot more than we think we are.

Advertisements

Tags:

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: