Peregrine Falcon chicks: Week 4

June 16, 2024 in Peregrine Falcon Woburn

During the fourth week after hatching, peregrine falcon chicks (eyases) continue to undergo significant changes in preparation for fledging.

Day 22-24:

– Feather Development: By now, the chicks have a substantial amount of juvenile feathers, especially on their wings and back. The down feathers are mostly replaced by these juvenile feathers, which are darker and more streamlined.
– Weight and Size: The chicks continue to grow, with their weight reaching between 500-800 grams (18-28 ounces). Females are typically larger than males.
– Preening: Preening becomes more frequent as they take care of their feathers. This behavior helps ensure their feathers are in good condition for future flight.

Day 25-27:

– Wing Exercises: The chicks engage in vigorous wing flapping to strengthen their muscles. They may even start to lift slightly off the ground, practicing for their first flight.
– Mobility: Their movements become more coordinated and confident. They explore the nest area more thoroughly, hopping and walking around.
– Feeding: The parents continue to bring food, but the chicks may start to eat more independently. They can tear apart small pieces of meat on their own, though they still rely on their parents for larger prey.

Day 28:

– Social Interactions: Interactions with siblings become more complex and frequent. They engage in playful mock battles and other social behaviors that help them develop their hunting and survival skills.
– Vocalizations: The chicks’ vocalizations become more varied and sophisticated. They communicate more effectively with their parents and siblings.
– Independence: While still dependent on their parents for food, the chicks show increasing signs of independence. They may start to watch the sky more intently, observing their parents’ hunting and flying techniques.

Overall Development During the Fourth Week:

The fourth week is a crucial period for peregrine falcon chicks as they prepare for fledging. The significant growth in their feathers and the development of their muscles and coordination are essential for their first flight. The chicks’ increasing independence and social interactions also play a vital role in their preparation for life outside the nest. The parents continue to provide food and protection, but the chicks’ growing autonomy signals their readiness to leave the nest soon.

Peregrine Falcon chicks: Week 3

June 9, 2024 in Peregrine Falcon Woburn

During the third week after hatching, peregrine falcon chicks (eyases) continue to experience significant physical and behavioral development.

Day 15-17:

Feather Development: The down feathers are gradually replaced by darker juvenile feathers, especially on the wings and back. These juvenile feathers are more streamlined and will eventually aid in flight.

Increased Size: The chicks continue to grow rapidly, with their weight now ranging between 250-400 grams (9-14 ounces). Their bodies become more robust, and their legs and feet grow stronger.

Hunger: Their appetite remains voracious, requiring the parents to provide a steady supply of food. The tiercel (male) continues to hunt frequently, bringing back prey which the falcon (female) helps to feed to the eyases.

Day 18-20:

Mobility and Coordination: The chicks’ movements become more coordinated. They start to stand on their feet more reliably and may take short, wobbly steps around the nest. This increased mobility helps them exercise their growing muscles.

Preening and Wing Flapping: They begin to preen more frequently, taking care of their developing feathers. Wing flapping becomes more common as they start to build the strength necessary for flight. These flapping exercises are crucial for developing their pectoral muscles.

Social Behavior: Interactions between siblings become more complex. They may engage in mock battles, which help them develop hunting and defensive skills. These playful activities are essential for learning social hierarchies and improving coordination.

Day 21:

Further Feather Development: By the end of the third week, the chicks have a noticeable amount of juvenile feathers. They still retain some of their down, but the sleek, darker feathers are becoming more prominent.

Weight and Size:Their weight continues to increase, with females generally larger than males. By now, the chicks weigh between 350-550 grams (12-19 ounces).

Vocalizations: Vocal communication becomes more sophisticated. The chicks use a variety of calls to communicate with their parents and each other, often demanding food with loud, persistent cries.

Independence: While still heavily reliant on their parents, the eyases begin to show more signs of independence. They explore their immediate environment more confidently, occasionally venturing to the edge of the nest.

Overall Development During the Third Week:

The third week is a period of intense growth and physical development for peregrine falcon chicks. Their transformation from fluffy, down-covered eyases to more sleek, feathered juveniles is well underway. The increased mobility, coordination, and strength they develop during this period are critical for their upcoming stages of development, particularly as they prepare for fledging. The parents continue to play a vital role in providing food and protection, but the chicks’ increasing independence and curiosity signal their gradual transition toward self-sufficiency.

Peregrine Falcon chicks: Week 2

June 2, 2024 in Peregrine Falcon Woburn

The growth and development of peregrine falcon chicks during the first two weeks after hatching are rapid and fascinating. Here’s a detailed overview:

First Week (Days 1-7)

Day 1-2:
– Hatching:The chicks, known as eyases, hatch after about 33-35 days of incubation. They emerge from their eggs with the help of an egg tooth, a small, temporary structure used to break the shell.
– Appearance: They are covered in white down feathers and have closed eyes. They are very small and weigh around 35 grams (about 1.2 ounces).
– Dependence: The eyases are highly dependent on their parents for warmth, protection, and food. The female, known as the falcon, broods them almost continuously to keep them warm, while the male, known as the tiercel, hunts and brings food.

Day 3-4:
– Feeding:The parents begin feeding the chicks small pieces of meat, often several times a day. The falcon tears food into tiny, manageable pieces to feed the eyases.
– Growth: The chicks start to gain weight rapidly, approximately doubling their birth weight by the end of the first week. Their digestive systems are efficient, and they produce a lot of waste, which is removed by the parents to keep the nest clean.

Day 5-7:
– Eyes Opening: By the end of the first week, the chicks’ eyes start to open. Their vision, initially limited, begins to improve, allowing them to start recognizing their surroundings and parents.
– Mobility: The eyases become more active and begin to move around the nest, though their movements are still quite clumsy.
– **Vocalization:** They start to make more vocalizations, calling out for food and interacting with their siblings and parents.

Second Week (Days 8-14)

Day 8-10:
– Feather Development: The down feathers begin to grow thicker, providing better insulation. The chicks still rely heavily on their parents for warmth, but can tolerate short periods without brooding.
– Appetite: Their appetite continues to increase, and the parents must hunt frequently to provide enough food. The tiercel often brings prey to the nest several times a day.
– Weight Gain: By the end of the second week, the chicks’ weight continues to increase rapidly, reaching around 150-250 grams (5-9 ounces), depending on food availability and individual variation.

Day 11-14:
– Further Development: The chicks’ eyes are fully open, and their vision sharpens. They become more coordinated and start to practice using their talons and beaks, essential skills for later life.
– Social Interaction: The eyases interact more with each other, sometimes engaging in playful tussles. These interactions are important for developing their social and physical skills.
– Independence: They begin to show brief signs of independence, such as preening themselves and exploring the nest area more actively. However, they are still completely reliant on their parents for food and protection.

Overall Growth and Development:
During the first two weeks, peregrine falcon chicks experience significant growth and development, laying the foundation for their rapid progression to fledging. Their physical development is complemented by increasing awareness of their environment and social interactions, setting the stage for the skills they will need as fledglings and eventually, as adult hunters. The parents’ role is crucial during this period, providing continuous care and an abundant supply of food to support the chicks’ rapid growth.

Lawrence Peregrines: male on brick smokestack

April 8, 2024 in lawrence peregrines

Mon. April 8, 2024 under clear skies, wind SW at 3MPH, and temp at 39F.

Had a nice visit looking to get an update on the local peregrines with breeding season getting in full swing! After a full tour around the Ayer Mill Clock Tower, moved on to scout out other nearby regular perch locations. From Merrimack Street just west of the clock tower, observed a peregrine chasing pigeons just west of the Mill240 complex. Tracked it in flight until it landed near the top of the brick smokestack by the Pacific Mills complex.  This male peregrine with alphanumeric black over green leg bands (78/AB), began to preen itself.

One thing the peregrine falcon does a lot is preening. Many hours are spent each day is spent on the care of feathers, beak, cere and feet. Without well preened feathers the peregrine could become soaking wet when it rains. Feathers that are not well groomed may cause drag when flying. When preening they also remove parasites from their feathers and skin. Preening birds run their beaks through their feathers or scratch their heads with an outstretched toe. Minutes later, the peregrine lifted off in flight!

We’ll continue to monitor the local area for any sightings of a female peregrine. We receive lots of emails from peregrine watchers that follow the webcam. A fellow peregrine saw the resident male in the box with a juvenile plumaged female on Tuesday! This was the first time in months that there has been any activity inside the nest box. The banded male flew in first, followed by the young female. There was lots of vocalizing and bowing before he left.  She tried to make a scrape, then flew off.  Stay tuned for more!!

Lawrence Peregrines: week of May 15, 2023

May 24, 2023 in lawrence peregrines

May 15, 2023 under sunny and clear skies, wind from W at 10MPH with gusts, and temp at 72F. The female was seen just before 10AM perched near the top of the red brick Pacific Mills smokestack.

May 16, 2023 under mostly clear skies, wind SW at 13MPH, and temp at 64F. Finally we have a sighting of the male again, perched on a south facing rooftop, overlooking the Merrimack River, on a building that is part of the Pacific Mills complex.

Lawrence Peregrines: week of May 1, 2023

May 24, 2023 in Near the Clock Tower

May 2, 2023 under overcast skies, wind from E at 8MPH, and temp at 51F. The sightings of the Lawrence Peregrines have been less regular compared to eight weeks.  The first stop today was around the Pacific Mills red brick smoke stack. The young female was seen moving around the gear near the top. This photo shows her jumping and landing near by with wings full outstretched.

Ten minutes later, after moving over to the Clock Tower, discovered the banded male perched on the pole that extends out from the nest box. The plumage on the adult male is notably different than the young female, with dark gray coloration compared to the brownish tones on the female.

Lawrence Peregrines: week of April 24, 2023

April 30, 2023 in lawrence peregrines

April 24, 2023 under overcast skies, light rain, wind E at 5MPH, and temp at 52F. Made a late afternoon visit, started on the north side of the river, and scanned all of the usual perch locations. Found a falcon perched on the Clock Tower and moved closer for better looks. Turned out to be the young female. She was on one of the ledges at 10AM, diagonally above the clock face.

At sunset time, checked the web cam and found the male inside the nest box. He was in and out a number of times, but not joined by the young female.

April 25, 2023 under mostly cloudy skies, wind E 7MPH, temp at 56F. Stopped by the Clock Tower this afternoon and initially sighted the male Peregrine perched on a lower NW ledge. Minutes later the female arrived and landed on an upper ledge. The male then went into a series of swinging flight moves on the west side of the tower. Later he landed joined the female on the upper ledge, before departing in flight to the NW. At no time has there been any observed copulation activity between these two falcons.

April 27, 2023 under partly sunny skies, light winds and temp at 54F. While scouting around for the Peregrines, around 10:30AM, in the extended area around the Clock Tower, made a sighting on the north side of the Merrimack River. Both Peregrines were seen tucked into the gear near the top of the red brick smoke stack on the west side of the Pacific Mills complex. This has been a very regular perch location this year.  The female is in the upper right quadrant of the photo and the male more to lower left.

On Saturday morning while looking through the web cam, spotted the female perched on the pole outside of the nest box!

That’s it for this week….stay tuned!

Lawrence Peregrines: week of April 17, 2023

April 23, 2023 in lawrence peregrines

April 18, 2023 under mostly cloudy skies, very breezy with wind from SW at 22MPH, gusts to 31MPH, and temp at 55F. INitial stop along Merrimack Street looking NE towards Clock Tower and scanning all known perch locations. Discovered the two year old unbanded female in a ledge diagonally above the 2:00 setting on the large clock face. She was enjoying some type of snack provided by the banded male.

Minutes later she lifted up and off in flight heading westward and away from the Clock Tower.

At 3:21, after circling the tower in flight, the male came roaring in, circling the tower, and then landing and moving inside the nest box. The young female followed right after him and this image shows her arriving into the nestbox!

Quickly pulled out my cell phone and gained access to the nest box webcam to catch looks of the male and female tilting forward and head bowing towards each other, a normal routine in the courtship rituals between Peregrine Falcons. The male leg bands are clearly visible on his lower left leg. So the big question continues, what may happen next, and is the other female already incubating eggs nearby?

A bit later, the male and female regrouped on the upper ledge, diagonally above the 2:00PM clock face. The female continued to feed on prey left earlier by the male. They spent a few minutes on the ledge together before the male lifted off in flight. The mystery continues……

April 19, 2023 under overcast skies, wind W at 13MPH with gusts to 21MPH, and temp at 50F. After initial scouting on the north side of the Merrimack River, discovered the male perched atop the red brick Pacific Mills smokestack located at the north end of the Casey Bridge. After watching a few minutes, also observed the young female. A minute later, she lifted up and launched into flight towards the river.

She returned shortly and perched near the male. She started to lean forward and make loud begging type calls directed at the male. A short while later he took off in flight and headed towards the Clock Tower.

April 20, 2023 under clear skies, light winds, and temp at 59F. After a number of random online nest box checks during the day through the webcam, spotted activity with both the male and the young female. Yet again, the courtship rituals continue with the male performing classic head low bowing along with eechip vocalizations. The image below from the webcam shows these actions.

A short while later, had a chance for direct observations, and found both falcons perched together, in close proximity, on the south side of the red brick Pacific Mills smokestack. The male was perched in the bright sun and the young female back a bit and in the shadows from my vantage point. Still no sightings, nor any sign of activity for the adult female. No way of knowing if she is still around and quietly incubating eggs nearby. The mystery continues……

On Sunday afternoon, under overcast skies, light rian, wind E 10 MPH, and temp at 47F, while online during a plane ride home, made a quick check on the falcons and found both the male and young female in the nest box. They continued with pair bonding and courtship ritual activities. The male continues is in the back, leaning forward and bowing his head low.

That’s it for this week….stay tuned!

Lawrence Peregrines: week of April 10, 2023

April 16, 2023 in lawrence peregrines

April 10, 2023 around 5:30PM, under clear skies, wind S at 5MPH, and temp at 34F. Observations made from South Canal Street just west of the Clock Tower. At first the male was seen perched atop the weathervane on the landmark Ayer Mill Clock Tower. For these local Peregrines, this is one of the most frequently used perch locations with excellent 360 views.

Minutes later, a second Peregrine arrived and spent time with the male, also perching on the weathervane. The two then launched in flight making large flight circles. It appeared to possible be a second year female. A bit later, three Peregrines were seen in flight with the females going at in a number of aggressive flight moves, even locking talons and rolling upside down while descending in flight. It was very dramatic. From a distance, this image below, documents the interactions close to 6:20PM.

April 12, 2023 under clear skies, wind W at 13MPH with gusts to 21MPH, temp at 70F. Observations made from South Canal Street on the west side of the Clock Tower. The male was seen perched on NW corner railing above the clock face. It had to make many adjustments due to the strong wind gusts. It lifted off in flight and provided nice views of the leg bands.

The male circled the weathervane a number of times and was in soaring mode with little wing flapping needed to maintain altitude. In this image below it was just turning on the west side of the upper roof and enjoying the wind with no distractions in sight. Minutes later, the male soared off to the NW and slowly out of sight!

April 15, 2023 under clear skies, wind NE at 10MPH, and temp at 64F. Out looking for the Peregrines on a sunny Saturday afternoon. There are many regular perch locations around the Clock Tower, and sometimes, you have to check two or three times to make sure you don’t miss. After multiple scans all around the tower, discovered the new two year old female perched on the SE corner of the roof railing, well above the clock face. She was facing NW and offered side views showing a white eyebrow and much heavier and thicker chest streaking. This female continues to be fed and cared for by the resident male, so stay tuned to see where this goes!

See you next week!


Lawrence Peregrines: week of April 3, 2023

April 9, 2023 in lawrence peregrines

On Sunday, April 2, 2023 the Peregrines were no where to be seen around the nest box. The same was true for Monday, April 3, 2023. Increasingly likely that the female has redirected her egg laying to an alternate location, perhaps again, under the nearby Casey Bridge. But wait….on Tuesday, April 4, in the late afternoon, the female was observed on the SW corner roof of the New Balance building. She was enjoying a late afternoon snack under clear skies, wind E at 10MPH, and temp at 57F. In tis image she is cleaning her bill against the edge of the roof!

Minutes later she lifted off in  flight towards the west, looped around and landed on a ledge just below a corner of the clock face!

April 5, 2023 just before 7AM, under overcast skies, wind E 15, and temp at 44F. The male was seen yet again mulling around in the gravel lined nest box, working overtime to prepare the nest scrape, and to encourage his mate to lay her eggs in the nest box. In this image, captured from the NB web cam, he displays his pair of leg bands. On the left leg you’ll see the alphanumeric black 78/green AB, and the right leg the silver federal band. So far, we are still standing by to see what happens…..

April 5, 2023 around 5:30PM, under overcast skies, wind E 6MPH, and temp at 40F. While out scouting for the Peregrines, the male was initially seen perched on the SW corner of the roof atop the Mill240 building. He was facing east and into the wind, then took off in flight towards the Ayer Mill Clock Tower. Minutes later, the male was found again on the SW corner on one of the roof tops at the New Balance building.

For the rest of the week, no sightings of the Peregrines in the nest box through the web cam or from other sightings at street level….stay tuned!