27 April

The end of incubation is in sight, and soon we should have chicks. Bell laid her first egg on 3/21 at 2336, the second on 3/24 at 0506, the third on 3/26 at 0724, and the fourth and final egg on 3/28 at 1314. Incubation usually starts with the third egg and lasts about 32 - 35 days. Last year, the chicks hatched on 5/2 and 5/3; this year, since she laid a little earlier, we expect hatching somewhere between 4/29 and 5/2. Embryos require heat to develop. Incubation transfers heat to the eggs, through contact between the eggs and the adults' brood patches. During the first half of incubation, the embryo is more or less free-floating in the shell. When the adults turn the eggs, this prevents the embryo sticking to the inside of the shell. If it did, its life support system within the shell would not form completely, and the embryo would eventually die. During the second half of incubation, the embryo becomes fixed within the shell as it moves into position for hatching. So, although incubation is tedious to observers, there's a lot going on inside those beautifully marked eggs.