How many eyasses are in this bunch of fluff?  3 eggs have hatched.  It looks like the fourth will not, but this is not unusual.  Peregrine eyasses grow at an incredible rate.  By the time they are six weeks old they will be as big as their parents.   Each week you will notice changes in their appearance and behavior.  During the first week, the eyasses can’t do much - except eat! 

There are several feedings per day.  Wildlife biologist Marcel Gahbauer tells us:  "…. the chicks at a young age already scream for food incessantly, regardless of how recently they have been fed.  This will only increase, and eventually you will see both adults away from the nest most of the time, for as long as one or the other is present, the chicks will be clamouring for food from them, even if they have none." 


SW spends most of her time keeping them warm if the weather is cool, since they cannot regulate their body heat and Boomer does most of the hunting at this point Mr. Harvey Webster, Director of Wildlife Resources at the Cleveland Museum of Natural History, tells us that even with cold weather or heavy rain, “… is a tribute to S/W that she can create a warm and dry sanctuary for the chicks with her own body. The parents, in brooding the chicks, provide a source of warmth.  In fact the temperature closest to the brood patch on S/W's abdomen might be close to 100 degrees F.  The brood patch is featherless and highly vascularized to provide maximum surface area for heat transfer”. 

With warmer weather, SW may leave the little ones uncovered a bit more for us to see. 


Mr. Scott Wright, peregrine falcon nest monitor at this site for almost 20 years, has been visiting the nestsite.   He is careful not to upset Boomer, who isn’t used to people and does not like anyone close to his family.  Here is Boomer staring through the skyscraper window at Mr. Wright.

Did you figure out 2 reasons why peregrine falcons prefer city life to life in the wild?  One reason they have moved into cities is because there are so many birds available to hunt year-round.  Of course, there are lots of pigeons, but peregrines like to dine on a wide variety of species of birds.  Here is a picture of SW just leveling out of a hunting stoop after chasing some prey. 

Another reason peregrines like to live in cities is because they lack predators.  After the peregrine falcon becomes a mature adult, it has few predators and falcons rule the skies, but while the eyasses are helpless the peregrine parents must watch over their young to protect them.  The great horned owl has been the greatest threat to peregrine eyasses, but they are rarely seen in cities.  Despite this fact, Boomer and SW are always on guard for anything that comes close to their territory.   Here is Boomer keeping watch.

The falcons don't like intruders in their territory, either human or other birds, and volunteer nest monitor Mr. Wright reports that a lot of turkey vultures have been passing over Cleveland lately and “SW is always looking up at them”. 

A turkey vulture is a very large bird, with a wingspan of about six feet, while a peregrine is about the size of a crow.  An eyewitness described seeing a male peregrine chase a turkey vulture several years ago: “He actually landed momentarily on the vulture’s back and I could see feathers falling to the ground.  After the attack, the vulture flew faster than I have ever seen a vulture fly--with the peregrine right on his tail.  It was quite an aerobatic show with both birds spinning and looping in the air.”  


Over the years Mr. Wright has reported that the male falcon (usually it's the male) has chased off interlopers much larger than himself, including bald eagles and a great-horned owl, as well as hawks and others who dare to cross the Falcon No-Fly Zone.  Peregrines are fierce predators and sometimes fight, if they must, to protect their nest.  Several times, SW and her mate have dive-bombed human window washers who came too close to the nestbox. 

One of the best stories Mr. Wright tells is when he watched a male chase the Goodyear Blimp during a Cleveland Indians game. 


Mr. Wright is guessing there are two females and one male.  Can you guess why?


For more about falcons, go to:





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Tags: birds, chick, eggs, eyass, falcon, nest, peregrine, territory




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