Wed. April 23: During the third week of incubation for a pair of nesting Peregrine Falcons (around days 14–21 after the last egg is laid), several key things happen in the development of the eggs and in the daily behavior of the adult falcons. Here’s a summary focused on your pair north of Boston:

Egg Development (Week 3)
– Embryo Growth: By the third week, the embryos are well developed, with feathers beginning to form, and their movements inside the egg become more noticeable. They are actively turning and shifting position, preparing for hatching.
– Vascularization: The blood vessels are fully extended in the egg membrane, aiding efficient gas exchange—essential as the chick grows.
– Yolk Absorption Begins: The yolk sac, which nourishes the chick, starts to be absorbed internally, especially near the end of this week.
– Hatching Preparation: By day 21, the embryos begin positioning themselves for pipping (breaking through the shell), which typically occurs between days 33–35 of incubation.

Adult Peregrine Behavior Patterns (Week 3 of Incubation)

Division of Labor
– Incubation Shifts:
– The female (typically larger) continues to do the majority of incubating, especially at night and during colder, windier times.
– The male relieves her for brief periods during the day—often mid-morning and mid-afternoon—allowing her time to feed, preen, and stretch.
– Exchange Ritual: They often vocalize softly to each other during nest exchanges, with the male bringing food and the female calling or even bowing slightly before rising off the eggs.

Foraging and Food Delivery
– The male is the primary hunter during this period.
– He catches small to medium birds (e.g., starlings, pigeons, shorebirds) and delivers them to the female.
– Sometimes food is cached nearby, but during incubation, fresh delivery is preferred.

Nest Defense and Territory Vigilance
– Both adults remain highly vigilant.
– The male frequently perches on nearby vantage points to scan for intruders (other raptors or people too close).
– They may engage in aerial displays or alarm calls if disturbed.

Rest and Maintenance
– The female rests frequently while incubating, shifting slightly every 20–30 minutes to rotate the eggs and maintain even warmth.
– The male*may also be seen preening, calling softly, or engaging in short flights.

March 25, 2025: News from the Lawrence Peregrine Nest! Throughout March 2025, Peregrine watchers on the New Balance falcon cam observed the resident female showing strong signs of egg-laying. Special thanks to our friends at New Balance for keeping the webcam running! She frequently visited the nest box, rearranging gravel, forming a nest bowl, and regularly hunching over it as if incubating. She also spent long periods on the lateral perch pole outside, watching over her territory. All signs suggest she’s ready to lay her first egg—stay tuned for updates!

March 26, 2025: Exciting News: First Egg Arrives!

Overnight, our resident female laid her first egg, marking the first use of this nest box in years! Right on schedule for late March, she’ll likely lay additional eggs every 48 hours, starting incubation with the next-to-last egg. At this location, we’ve often seen 4 eggs per year, but from different mating pairs. Thanks again to our friends at New Balance for keeping the falcon webcam running.

March 27, 2025: Under sunny skies and breezy weather with temp highs near 50F. The female tends to her first egg on and off throughout the day. She devotes sometime to incubating and also just perching in the sun on the lateral perch pole. The second egg will hopefully drop overnight tonight. The view below shows her in the midst of moving around near the single egg in the middle of the afternoon after the sunlight had cast directly on the egg.