Incubation is the boring segment of the bluebird life cycle. It’s about like watching grass grow. Nothing in the nestbox changes for a couple of weeks. It’s been cool this week with temperatures below freezing.
Mama enjoys a mealworm breakfast after a frosty night in the box. Click to enlarge.
Mama II began sitting on her eggs 25 March. Bluebird eggs hatch in 12-14 days. I normally use 13 days in my estimates. But, since it’s cool, I’m going with 14 this time. That means the bluebird eggs should hatch ~09 April.
Although nothing visible will be going on with the eggs, the danger from HOSP remains. I still have a handful I can’t trap and Daddy II is not as protective of his turf as my old Daddy. Worries me some.
Have you ever wondered why bluebirds and other birds like jays are blue? Ornithologists have known for decades that red and yellow colored birds get their pigmentation from their diet. In the past few years Yale ornothologist Richard Prum has discovered why bluebirds are blue.
A Stellar’s Jay I photo’d in Santa Fe.
Prum discovered that as a blue feather grows, something amazing happens. Inside each cell, stringy keratin molecules separate from water, like oil from vinegar. When the cell dies, the water dries away and is replaced by air, leaving a structure of keratin protein interspersed with air pockets, like a sponge or a box of spaghetti. When white light strikes a blue feather, the keratin pattern causes red and yellow wavelengths to cancel each other out, while blue wavelengths of light reinforce and amplify one another and reflect back to the beholder’s eye. The result: blue, an example of what scientists call a structural color (as opposed to a pigmented color) because it’s generated by light interacting with a feather’s 3-D arrangement. And different shapes and sizes of these air pockets and keratin make different shades of blue.
First Brood Summary
- First sign of nest building 09 March
- Nest completed 15 March
- First egg laid 18 March
- Second egg laid 19 March
- Third egg laid 20 March
- Fourth egg laid 21 March
- Fifth egg laid 22 March
- Incubation begins 25 March