Incubation
With their clutch of 4 eggs completed, the incubation phase of the falcons’ nesting cycle has begun in earnest. When tuning in to watch the cam, you can therefore expect to see a bird on eggs. Both sexes incubate, although the female does a greater proportion of the work. While in incubating posture, the female can be distinguished from the male by her larger size in the camera frame; her orbital ring (bare skin around the eye) and cere (the fleshy base of the bill) are pale yellow, whereas the male’s are a bright yellow-orange.
Incubating female
Incubating male
Incubation bouts can last up to several hours before one bird relieves the other of its duties during what we call an incubation exchange. The eggs may be visible for a few to several minutes during exchanges, and periodically as an incubating bird stands to change its position. Watch an incubation exchange from April 15 below – this was one of 6 such exchanges documented on that date.
Although the birds were seen sitting on eggs shortly after each was laid, proper Incubation typically begins once the next-to-last egg is produced. Incubation is estimated at 33-35 days; we would expect the eggs to begin hatching sometime between May 10 and 12.