Apr 222013
 

I’ve been having a lot of fun watching the Boulder County Fairground’s ospreys this season. The web cam is trained right on the nesting platform.

First it was waiting expectantly for the first bird to return, and then waiting (less patiently) the full week for the second, and now waiting for eggs (and hoping they time things well, given the deep snows we’ve been having.)

It finally dawned on me that it would be interesting to know which was the male, and which the female, and that this was a time where I could figure it out. Right now the birds are copulating regularly, with the male on top.

Here is what I’ve observed:

Female has a larger (wider) back-of-the-head marking…

From behind, you can see the female has a larger/wider marking on the back of her head; it is like a black diamond. The male’s marking is much smaller/thinner; it is closer to an inverted T. This makes identifying the birds relatively easy from the back.

Female Osprey on the left, Male on right

Female Left, Male Right

Female has speckled breast….

The female’s breast is heavily speckled with markings. The male’s breast is pretty much pure white.

Female osprey has a speckled breast, male is white.

Speckled Female

 

White-breasted Male

White-breasted Male

 

Additionally

The female is larger, but (to my eye via this camera) only barely, such that it would be hard to use this when they are together and next to impossible outside of that.

Right now the female is spending most of her time at the nest, with the male bringing her food.

See some #fgosprey tweets

These ‘Fairground Ospreys’ are discussed on Twitter with hashtag #fgosprey.