Author: Web Site Administrator

The youngest peregrine falcon nestling, who hatched on April 28, is now one week old, while its three older siblings are approaching two weeks. With each passing day, these young falcons—called eyases—are growing stronger and more alert under the watchful care of Frida and Mango.

At this stage, they are still covered in fluffy white down and rely entirely on their parents for warmth and food. They are often observed sleeping but also preening their downy feathers. Their eyesight is improving and they are starting to look around as they explore their nestbox. Feeding time is frequent, with the adults carefully tearing food into small, manageable pieces of prey. We’ve seen them bring in a variety of prey, mostly songbirds, including mourning doves, blue jays and homing pigeons. The larger the young get, the more prey they need, as they tend to eat around half their body weight each day.

Looking ahead, biologists are planning to visit the nest on May 19 to carefully band the eyases. Each band placed on a peregrine falcon chick has a unique combination of letters and numbers, kind of like a falcon’s license plate! These bands allow biologists to identify individual birds years later—sometimes from hundreds or even thousands of miles away—just by spotting them and reading the code on their band.

On the morning of April 28^th viewers noted the presence of a fourth hatching! This is right on schedule for when it was laid, which was five days later than egg #3 and same time period after other eggs hatched. What a happy surprise, as I’m sure most of us were thinking that if the fourth didn’t hatch soon then it wouldn’t. We’ve seen how quick parental care shifts from incubation to brooding and feeding young. In a few days the oldest nestlings will be a week old. The adults will continue to brood them as they are not quite able to regulate their body temperatures. During the day, the adults will start to leave them unattended for short periods when temperatures are at their warmest. We are keeping an eye on them for signs of trichomoniasis, which is a pigeon borne disease that can be fatal to young PEFA if not treated.

Incubation continues with a little housekeeping.  As of April 9, we are at day 20 of incubation, which began after the third egg was laid. The fourth was laid five days later. Falcons typically incubate for around 30 days, so we should start to see signs of hatching late next week. Once eggs begin to hatch, attention of adults will be directed towards their young with less going to the fourth egg. We shall see if it does hatch.

This week Kathy Clark, Chief/NJDEP Fish & Wildlife/ENSP received a report of BN/24, a female that was banded at the Union County Courthouse in 2023. She is now frequenting a tall building at Saint Joseph’s University in Philadelphia. She has been observed with a banded male falcon (BH/40), that fledged from a nest atop the NJ side of the Walt Whitman Bridge in 2022.

Students and staff have noted the presence of the falcons since fall 2024 and even wrote about them in the school paper. They have been seen perching, feeding and mating on Barbelin Hall. It looks like the site could be a great location for them to nest. Add an igloo atop the roof, add some gravel and you have a new falcon nest site.

Karl Platzer reports that BN/24 has been observed daily since Fall 2024, usually perched on the Barbelin Hall bell tower at Saint Joseph’s University Philadelphia campus (AKA Hawk Hill).

In other news, the pair continues to incubate the four eggs. In another two weeks we will be watching for hatching.

How can you not love getting surprised by a fourth egg! I had a feeling that by saying “it appears that no more eggs will be laid” another would be laid.  Peregrines typically lay 4 and sometimes 5 eggs. The fourth was laid at 2:26:02 PM on March 25. It just took Frida a little more time to develop her last egg (will there be one more?). With that said, incubation is still in full swing.

It appears that no more eggs will be laid this spring, as the forth egg would have been laid over the weekend. This is not abnormal, as their average clutch size varies from 3-4 (sometimes 5). With incubation underway, this puts hatching to begin towards the tail end of the second full week in April.

Over the next several weeks, we will watch as the pair incubate the eggs where the female does the majority of incubation duties. She will occasionally get breaks to stretch, feed and preen where the male takes over. They will shift/roll eggs to ensure they develop properly several times a day. This prevents the developing embryo from sticking to the shell and ensures even heat distribution.

Happy Spring! Frida and Mango are now incubating three eggs! The second was laid on March 17 and the third was laid early this morning. Now that they have almost a full clutch of eggs, they will be incubating them more. Their typical incubation period lasts 28 days and the last egg should be laid late tomorrow or early Saturday. This puts hatching close to the beginning of Earth Week. Delaying incubation is a natural adaption where all eggs hatch very close to each other and gives all young a better chance of surviving, where with ospreys, they start incubating after the first egg is laid and there are usually more differences in ages of young. This accounts for shortages in prey where only the oldest may survive if there is not enough food.

On the morning of March 15 at 6:30am, viewers got their first glance of the first egg. We knew egg laying was close as the pair has been observed copulating, performing eee-chup courtship (bowing) displays on camera. Frida has also been spending more time in the nest box preparing her scrape, which is a shallow depression in the nest box where eggs are laid. Peregrines do not build a nest like hawks, eagles and ospreys and instead create a shallow depression in gravel, soil and other debris to nest. This is often the case on ledges of cliffs and in our human dominated landscape, it also includes tall buildings and sometimes flowerpots left unattended on upper floors of apartment building patios. The second egg should be laid sometime over night or tomorrow.

On another note, we decided to wait to remove the worn green carpet for perching. Introducing disturbance to the pair before laying began would not have been good. Instead, we will swap this carpet when we visit the nest for a health check after the young hatch in around 45 days (late April).

Lastly, we opened up chat on two of the live streams on our YouTube channel, so you can watch and talk with other viewers. BW

Frida, the female peregrine falcon, sits in the nest box that is located on the top of the Union County Courthouse in Elizabeth.

Here we go! Those watching closely have seen the pair more and more lately as they strengthen their pair bond by mating and bowing to each other in the nest box. Some light maintenance will occur sometime in the next two weeks. The green carpet that is worn will be replaced, prey remains will be cleaned up, and lens covers will be cleaned.

Some seasonal notes. Last year the first egg was laid on March 16. In 2022 + 2023 it was March 19, so who wants to bet that an egg will be laid during the third week of March? I’m betting it will be earlier than last year. Time will tell. Either way, it will be great to focus on wildlife and see some new life after what seemed like a really cold, long and dark winter.

On Tuesday morning, June 11, 2024 those watching the Union County Falcon Cam saw the hatch on the roof open and a young falcon was put out on the roof with food.  An effort to foster a fledgling falcon from another nest was attempted. The young falcon fledged from a nest under I-295 and was recovered from the river beneath. After spending a few days in rehab, the decision to foster here was made, as going back to their bridge nest site would have been much more risky, with lots of fast moving vehicles and a river below.

Fostering is a technique that has been successful in many prior, similar situations. It is important for fledgling falcons, who still rely on adults for food, to be a part of a falcon family.

This time the adults reacted badly, acting like the juvenile falcon was a competitor. It may be that the timing was just not close enough in terms of the fledging stage their own four chicks were at, even though they were all still close to the building/roof and clearly dependent on the adults.

We re-activated the live streams and have not seen BN/55. We will be watching for sightings of her here and elsewhere. We’re thankful for the support of our faithful UC Falcon Cam viewers, wildlife rehabilitators, and volunteers who helped with this mission.

Anyone who finds a grounded or injured falcon or hawk should call the nearest licensed wildlife rehabilitator or the city/municipal Animal Control office for assistance.