29 March 2026
When peregrines have eggs both parents incubate. The female incubates all night. The male takes turns with her during the day. This trading of incubation duty is called a nest exchange.
On Friday 27 March Carla and Ecco made eight nest exchanges from pre-dawn to evening.
1. Ecco arrives
- 6:58 am — Ecco relieves Carla. He brought her breakfast.
- 8:45 am — Carla’s turn
- 10:55 am — Ecco
- 12:45 pm — Carla’s turn
- 3:14 pm — Ecco’s turn
- 3:49 pm — Carla
- 5:05 pm — Ecco takes over so Carla can eat dinner.
- 6:01 pm — Carla arrives to spend the night on the nest
The amount of time the male incubates each day mostly depends on the female. If he arrives to relieve her and she says “no,” he leaves.
Tom and Azina at FaB Peregrines in the UK (Charing Cross Hospital, Fulham) are an extreme case. On 27 March she spent almost 23 hours on the eggs and only let him incubate for about an hour.
Most peregrine couples have a more equitable arrangement. In their heyday, Dorothy and E2 often waited after the first “no” to see if the answer would change. For example, when Dorothy came to relieve E2, sometimes he would not make eye contact, signaling that he wanted to stay. Dorothy would stand near him and wait patiently, sometimes for an hour, until he was ready to get up. See one of these episodes in 2012 at Reluctant Changing of the Guard.