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NEST SITE:
The Corbloc building, 80 King Street.

In March 2001, a pair of peregrine falcons was discovered in downtown St. Catharines at the Corbloc building.  Peregrine chicks were released in St. Catharines in the late 1980s, but adults have never nested in the city.

Please help us keep track of the peregrines!  We welcome your observations of this pair (or any other peregrines) by email 



St. Catharines Nest Site Reports:


Tuesday June 18, 2002
Marcel Gahbauer reports: 
I have received no reports of peregrine sightings from St. Catharines over the past month.  However, today we have confirmation that Mozart is now in Hamilton - see the Hamilton page for details.

Thursday May 9, 2002
Marcel Gahbauer reports: 
Unfortunately, Mozart and Constanza have decided not to nest at the Corbloc building this spring.  In fact, sightings in general have been scarce over the past six weeks.  However, Jim Yaki did inform us today that he has continued to see peregrines in St. Catharines "on a regular enough basis to assume there is still a resident bird or pair".  His most recent sightings are of a single peregrine hunting near the intersection of St. Paul and Ontario on Monday, and an individual today hunting over Ontario Street near the GM plant.

It is entirely possible that Mozart and Constanza are still in St. Catharines, having simply moved to a different neighbourhood from last year.  By extension, it could also be that they are currently nesting.  In order to ensure the safety of any possible chicks, it is important that we identify potential nest sites - if you have any sightings from the St. Catharines area, please share them with us by email

Tuesday March 26, 2002
Barb Wright reports:  My sister-in-law called to tell me that at 7:45am. today a large peregrine was sitting on the corner of the Corbloc building.

Sunday March 24, 2002
Jim Yaki reports:  After seeing the peregrine Wednesday in downtown St. Catharines I saw nothing of them until this AM (Sunday the 24th). At 9:00 the pair of birds were both on the corner of the ledge where last years nest was. After a few minutes one of the birds flew across the street to the Bell building and the other went out of sight down into the nest scrape. It remained out of sight for about five minutes. I assume this would be the female but I am not sure. When I left there was one bird on the nest corner and the other on the Bell building. It would seem that they are going to try again in the same nest location.

Alan Titley reports:  On Sunday morning from 10:30-12:00 noon I watched two Peregrine Falcons at the Corbloc nest site in St. Catharines. A female bird was perched on the ledge and in the nest box vocalizing and a male bird was flying around the building visiting the ledge every few minutes

Thursday March 21, 2002
Jim Yaki reports:  I went downtown last night (Wed Mar 20) at around 5:45 pm and sure enough
there was a peregrine on the Bell communication tower. About a minute after I arrived it took off and dove towards Ontario Street.  I walked to the corner of Queen and could hear the bird calling. It was making a series of swooping dives at something on the roof of the St. Catharines Standard building. There was a ton of pigeons all flying about quite close to the peregrine. At the time I guessed that on the Standard building was the mate and that it had just made a kill. I didn't know which bird was doing the swooping and "screaming" but I  assumed it was "begging" for some of the kill. After a few minutes it gave up and went back to the corner of the Bell building right opposite last years nest. It was still there when I left about 10 minutes later. I never did see a second bird, but I thought  it was safe to say they were both there.

Monday March 18, 2002
Alan Titley reports:  I was walking home from the grocery store yesterday (March 17th, 2002) and I spotted a pigeon wing on the sidewalk on James Street in downtown St. Catharines. This made me start looking around at the top of the higher buildings in town. I then saw what I think was a Peregrine Falcon hunting up and down King street. I also saw another bird resembling a Peregrine perched on the Bell Telephone building. 

Tuesday December 4, 2001 
Barb Wright reports:  My sister-in-law called me today to say that she saw a peregrine falcon yesterday (Dec.3) on the Federal Building, Church Street, St. Catharines. She also said that sightings of falcons have been mentioned recently in the St. Catharines Standard.

Tuesday May 15, 2001 
Marcel Gahbauer reports:   It has now been more than one week since the dummy eggs were placed on the nest ledge, and unfortunately Mozart and Constanza have shown very little interest in them.  It would appear we simply weren't fast enough in getting them in place to keep their attention, and we have learned a valuable lesson about how critical it is to respond very quickly in situations such as this.   As a result of Mozart and Constanza's lack of interest, we are calling off our plans to foster a chick in St. Catharines this year, as the odds of it being accepted by adults not tending to a nest are very slim, and the chance of rejection is simply too great to risk.

On behalf of everyone at the Canadian Peregrine Foundation, thank you sincerely to all of you in St. Catharines and beyond who have been so supportive of the proposed fostering attempt over the past couple of weeks.  We are very disappointed that we were not able to proceed as hoped.  There remains a slim chance that the pair may try to nest a second time on their own; failing that, we will have to hope that they continue to show an interest in this territory, and have better success in St. Catharines next spring.  

In the meantime, we will of course continue to monitor the activities of the peregrines, and welcome any observations by e-mail as always. 

Thursday May 10, 2001 
Marcel Gahbauer reports:   A couple of observers have now reported that Mozart and Constanza have been frequenting the St. Thomas Anglican Church on Ontario Street, and have also been seen at the opposite end of the Corbloc building from the nest tray on several occasions.  It's possible they are searching for an alternate site to lay a second clutch of eggs.

Tuesday May 8, 2001 
Marcel Gahbauer reports:  Mozart and Constanza have been somewhat slow to respond to the new eggs in the nest tray, but one or both adults have made brief visits to the site today.  They are definitely still around, and it may just take them a bit of time to adjust to the "return" of their eggs.  We encourage everyone to keep watching via the webcam and from the street this week to see whether the peregrines return to the nest tray (or alternatively, lay a new clutch of eggs elsewhere, which remains a possibility, given the frequent matings in recent days).  

Monday May 7, 2001 
Marcel Gahbauer reports:  Over the past few days, Mozart and Constanza have remained faithful to the area around the Corbloc building, and have also been seen mating on numerous occasions.  Since the peregrines are showing signs of continued interest in breeding activities, the Canadian Peregrine Foundation has decided to proceed with an attempt to foster a chick into the nest.  

The first step took place today, as three mock eggs (chicken eggs stained to appear like peregrine eggs in colour) were placed in the nest tray.  These are intended to lure the adults back to the nest for "incubation".  If the peregrines prove to be attentive in this manner, then the odds of a successful foster become more promising.  We encourage everyone to watch closely the behaviour of the peregrines over the coming days to help us evaluate the situation.  Please see the box above for more details on Project Foster.

Friday May 4, 2001 
Marcel Gahbauer reports:  The final egg has disappeared from the St. Catharines nest as of yesterday morning.  Though disappointing, this clarifies matters somewhat by supporting the theory of the eggshells cracking for some reason.  The question now is whether Mozart and Constanza will attempt a second clutch this year.

Wednesday May 2, 2001 
Marcel Gahbauer reports:  Just a quick update - the one remaining egg is still present in the nest, and Mozart and Constanza continue to incubate it regularly.  There is still no firm conclusion as to what happened to the other two eggs, though the most likely explanation is probably that they cracked for some reason and the remnants were eaten by the adults (probably during the night, which would explain why nobody observed this behaviour via the webcam during the day).  Further thoughts and comments on the situation are still welcome though.

Monday April 30, 2001 
John Fletcher reports:  Some disappointing news out of St. Catharines.  Sunday morning at 7:19 Constanza left the nest to expose only two remaining eggs.  She was off the nest without relief from Mozart until 7:36.  The temperature was around three degrees C.  I don't know how long the eggs can tolerate a drop in temperature but this seventeen minute absence on a cool morning concerned me.  Then at 7:09 Monday morning Constanza was on the ledge feeding  and left just one remaining egg exposed.  I can see no egg shells in the nest but the image is a little fuzzy so it is difficult to tell.  

Marcel Gahbauer comments:  This is a very surprising turn of events.  We will try to piece together what happened, but we need YOUR help.  If you watched the Niagara webcam at all on Saturday or Sunday, please e-mail me a brief description of what you saw (eggs, adults, anything else) and when. I'm hoping that with enough input I might be able to determine what happened - there are a number of possibilities, but none of them seem very likely.

I would also encourage everyone to monitor the nest very closely over the coming days.  It is possible the third egg will disappear too, and if this unfortunate event is to occur, it would be very useful to have the event fully documented.  On a more positive note, it's also possible that a fourth egg could still be laid.  

Regarding the time spent off the nest, this is probably not a serious concern.  Eggs can withstand a certain amount of exposure to the cold.  Until the full clutch has been laid, the eggs are frequently left unattended for extended periods before full incubation begins, and this does not cause any problems.  Even when the eggs are uncovered, one or both of the adults are usually very close by, so the likelihood of predators being able to grab an egg undetected is small.  Mozart and Constanza are inexperienced, though, so this may be one of the potential explanations of what happened.

I will post further observations and comments as we learn more about the situation. 

Saturday April 28, 2001
Marcel Gahbauer reports:  Several observers have reported seeing a third egg in the St. Catharines nest as of Friday evening.  This is somewhat unusual, as peregrine eggs tend to be laid overnight or in the early morning, yet as of early Friday evening, there were clearly still only two in the nest.  Will there be a fourth on Sunday evening or Monday morning? 

Friday April 27, 2001
Nadine Litwin reports: I lurked about downtown St Catharines for a while this morning ... long enough to see Mozart perched on the ledge just above Constanza while Constanza was intently incubating.  And incubating she is ... I saw one food exchange at the nest ledge, and when I checked the camera while Constanza was eating ... it looks like she's trying to eat and watch her eggs at the same time!... there were still two eggs.

Wednesday April 25, 2001
John Fletcher reports:  Great news!!  Watching the webcam this morning Constanza came off the nest at 7:19 to uncover a second egg right on schedule.  She seems to be protecting them against the cold but not incubating as of yet so hopefully there are one to two more to come.

Monday April 23, 2001
John Fletcher reports:  I looked in on the Niagara webcam this morning and there was the first egg at 6:50am.  I don't know when it arrived but it was absent Sunday at around 8:00pm when I last checked.  I was starting to worry!  (NOTE: check the link to the webcam at the top ofthis page).

Sunday April 8, 2001
Marcel Gahbauer reports:  After reading about Mozart and Constanza for the past two weeks, it was wonderful to finally be able to see them in the flesh today.  I spotted Mozart almost immediately, at the far north end of the ledge of the Corbloc building.  Constanza was not in sight, so I assumed she might be at the nest tray.  I wandered over to Helliwell's Lane and walked down the alley with my eyes to the ground, expecting to find some prey remains.  I found one brownish wing, likely from an Eastern Meadowlark, but nothing else.  However, I did notice that one wall of the CIBC building (and the ground below) was covered in whitewash.  I looked up, and sure enough, there was Constanza, tucked into a corner ledge of the CIBC building.

At one point Mozart took off and flew over to Constanza, clearly with the intent of mating with her - he hovered over her back, and was about to land, but her loud vocalizations deterred him and he retreated to the Corbloc by the nest tray, clucking all the way as if muttering to himself about his misfortunes.  It wasn't long before Constanza took off, not to reunite with Mozart, but to make a pass at the windows below him, in similar fashion to what John Fletcher and Jim Koolsbergen described last week.  She then abandoned this effort in favour of defending her territory against a couple of passing Sharp-shinned Hawks.  Though they posed no threat (especially since they were just migrating past the area), she gave very vigorous chase and forced the hawks to practice some considerable acrobatics to escape unscathed.  Constanza then remained aloft for a while, enjoying the strong wind as she soared over downtown St. Catharines.  During this time, Mozart lifted off too and relocated to the CIBC ledge where I had found Constanza earlier - it would seem that they both like this hidden spot.

Thursday April 5, 2001
John Fletcher reports:   I observed the pair from 8:20 to around 9:30 today and was very pleased to see several trips to the new nest box area.  The most interesting behavior was three separate flights at the Corbloc windows by Constanza.   The first one caught me by surprise and concerned me.  She flew at the window on the upper most floor about mid building just below the curved section.  She approached it at slow speed coming straight at it and then pulled up at the very last and presented her talons to the glass just brushing the surface.  She circled away came back and repeated twice more within a space of one minute.  On the second and third approach it was obvious she was not in danger and her actions appeared quite controlled and purposeful.  I can't say if it was the same window each time but it was the same area of the building.  I have heard of falcons going after their own reflections in the glass and her approach was not that different from Mozart's talon to talon exchanges with the interloping female a week and a half ago.  The general feeling I got was she was seeing something inside the window.  Two things gave me this impression, first she was not vocalizing or showing any signs of being threatened and second she seemed to approach the same window each time even though her circular approaches would have brought her reflection back too her in a different part of the building each time.  I did not have my wits about me to count across and identify the window but will if I see a repeat in the behavior.  I can only imagine what a sight that would have been from the inside of the window.

Wednesday April 4, 2001
Jim Koolsbergen reports:   Mozart and Constanza are still very active and attracting a steady flow of people. We saw them copulate several times on the CIBC building.   The peregrines are messy eaters and it looks like they want to keep the nesting box area clean. I have seen Constanza fly against the glass windows at Corbloc several times.  

Marcel Gahbauer comments:  While the description of Constanza flying at the windows may sound alarming, it is not as serious as it sounds.  We have observed female peregrines in Hamilton, Etobicoke, and Ottawa doing the same on a number of occasions.  Several people have suggested that this may be territorial behaviour, i.e. the female sees her reflection in the glass and attempts to drive away the intruder.  This seems to be the most likely explanation, but there are many other possibilities - if you would like to contribute your thoughts on this, please e-mail me. 

Barry Adams reports:  John Graham advises me that he has observed the birds spend some time rearranging the pea gravel in the nest box earlier in the day.  One of the birds stayed in the nest for over an hour.  Lynne Cloutier repeated to me the comments of one of the patrons of the coffee shop below about "all the bird heads" in the alley between 55 King Street and the Bell Canada Building. (We have watched the falcons feeding regularly on the southwest corner of the Bell Canada Building).

Tuesday April 3, 2001
John Fletcher reports:   I spotted one of the peregrines at the nest ledge when I first arrived at 4:20pm.  Within seconds the falcon flew across to the bell building where the other falcon was waiting.  They took up positions 3m apart and remained there until I left at 5:30.  I hoped to see a little more activity at the new nest box but at least they were keeping it in sight.

Jim Koolsbergen reports:   We were at the Corbloc again, this afternoon from 1:30 to 3:30 and witnessed lots of activity from Mozart and Constanza. There was a report in today's Standard about the placing of a nestbox. According to witnesses this took place late this morning. The falcons seem to have accepted the nestbox and have been in it this afternoon and also making lots of noise. In a small alley called "Helliwell Lane", between the Bell Canada and CIBC building you can see lots of feathers and body parts of all kinds of birds. We found a starling head wrapped in a peregrine feather on the sidewalk in front of the Bell Building.  Many people still come and watch.  We counted thirty-two people watching the peregrines from various locations along King St.

Eileen Martin reports:  Today someone from the Ministry came and placed a box for nesting in a more enclosed area by the ledge outside our office.  Mozart came over and checked it out first by sitting and scratching, and now Constanza is on the nest and Mozart is standing guard on the ledge above it.  It looks like they like it for nesting purposes! 

Marcel Gahbauer comments:  Just a note of clarification, regarding some of the above comments.  Early observations of the nest ledge suggested that drainage on it might be poor, and this was a concern of course in case heavy rain occurs during the nesting season.  Canadian Peregrine Foundation director Mark Nash constructed a nest tray on the weekend to fit the ledge, and it was installed this morning by the Ministry of Natural Resources.  We are delighted at how quickly the peregrines seem to have adopted the new box. 

Monday April 2, 2001
Carol Horvat reports:  Around noon today I observed Mozart and Costanza chasing a red-tailed hawk away from the Corbloc area. They came back and perched on the building across the street and were quite vocal.

Sunday April 1, 2001
John Fletcher reports:   I arrived at King St. today around 9:15 just in time to see Mozart fly from Corbloc across to the SW corner of the Bell building and mate with Constanza.  He then flew back to Corbloc and in a few moments disappeared heading east.  9:30 Constanza flew to the middle of the Corbloc building ledge.  She then got very agitated and while vocalizing loudly she walked rather quickly the half length of Corbloc on the ledge and kicked Mozart off the scrape.  He must have come in unnoticed from the south. This behavior seemed rather bizarre as the distance walked on the ledge of Corbloc was some 100 feet.  It just seemed odd that she wouldn't simply take wing and glide to the corner of the building.  Mozart went off on another flight and disappeared from view.  

I was joined on the street by two gentlemen who frequent the Beamer hawk watch then at 9:50 Constanza began vocalizing and as we scanned the sky expecting to see Mozart return we spotted two peregrines going right over King St heading east just above the buildings.  It was pretty clear one was the smaller male Mozart and the other an unidentified female.  There were two talon to talon encounters initiated by Mozart and then the female seemed to decide to run and she disappeared to the east with Mozart in chase.  Within a matter of 10 or 20 seconds Constanza followed suit, perhaps to ensure her virtue was being properly protected.  It seemed to the three of us observing that Mozart's defense of the territory was not as violent or aggressive as we expected but it was a defense none the less and perhaps he was a little wary of the larger bird.  It was a tremendous sight none the less and there were three of us who had all three birds in sight simultaneously.  By 10:15 Constanza was back at Corbloc and Mozart returned to the Bell building at 10:20.  What a great way to start the day...

Jim Yaki reports:  I was downtown this AM for a few minutes and again this afternoon at about 1 pm.  A couple of interesting occurences that I thought I would pass on. This morning at about 9:55 am a second female appeared. All three birds were in sight at one point. Mozart and the second female (I call it a female because it was noticeably larger than Mozart) appeared quite close to the nest corner and Costanza flew off after them. When we first saw the other female, she and Mozart were flying in tight circles but there did not appear to be any animosity between them. What caused us to notice them was Costanza's "screaming" and when we looked up there were the two birds, and then Costanza flew off after them. It makes you wonder if this is the same other bird as was reported Thursday and if so is there another resident in the area?

The second point of note is that this afternoon I watched Mozart bring half a kill to the nest corner. We couldn't see what became of it but both birds were present so it would appear as if he brought it to his mate. When I left the two of them were sitting on the south corners of the CIBC and Bell buildings, so she doesn't appear to be sitting on eggs yet. This was at 1 pm.

There were quite a few people downtown specifically to check them out. A few like myself brought there kids so it was good to see. It is shaping up to be an interesting spring!

Friday March 30, 2001
Marcel Gahbauer reports:  Some great photos of Mozart and Constanza have been taken by the lawyers at Chown-Cairns - the offices which the peregrines have made a habit of perching outside of.  Click here to see the photos on the Chown-Cairns page.

The latest news from Nadine Litwin is that she and Ministry of Natural Resources biologist Anne Yagi have confirmed that Constanza has created a definite nest scrape.  Though there are no eggs yet, all signs are certainly promising.

Thursday March 29, 2001
Marcel Gahbauer reports:  Lots of great news to share today!  First of all, Eileen Martin reports that Mozart's mate has been named Constanza (after Wolfgang Amadeus Mozart's wife).  She adds that Mozart and Constanza made the front page of the St. Catharines Standard, with a lengthy article accompanied by three photographs.  Several observers have commented to me that the local community has quickly taken these birds to heart, and that many pedestrians are walking around downtown with their eyes to the sky, trying to spot the new celebrities.  Since the pair is quite vocal and the buildings are not very high, observing the birds is quite easy.

This morning an intruder, thought to be another peregrine, was observed being chased from the territory by Mozart and Constanza.  This vigorous defense of their territory is another encouraging sign with respect to the potential for nesting here this spring.

Jim Koolsbergen reports:  Good news!!  The peregrine falcons are on the corner of the Corbloc building again today. We were there between 1:00 and 3:00 pm and they were quite active. Flying back and forth between the Bell Canada Building and the Corbloc. Many people on the street watching and also taking pictures.

John Fletcher reports:  I observed the falcon pair in St. Catharines this morning at 8:45; one was on the SW corner of the Bell building (the male I believe) and the other was on the NW corner of Corbloc.  Around 9:00 the male crossed to the Corbloc bldg and much vocalization followed then the larger bird went for a short flight and landed on the Bell building's antenna tower two thirds of the way up.  They certainly seemed protective of that ledge on the Corbloc building.  When I returned at 3:15 they were once again as they were in the a.m. and again an exchange of positions took place.  

Wednesday March 28, 2001
Marcel Gahbauer reports:  Nadine Litwin yesterday observed two copulations between Mozart and his mate.  More significantly, the female was observed trying to dig a scrape at the corner of the Corblock, suggesting that she is interested in nesting and may be almost ready to lay eggs.  

Tuesday March 27, 2001
Marcel Gahbauer reports:  Thanks to the quick help of our friends at the Ohio Division of Wildlife, we have learned that the male peregrine in St. Catharines is known as "Mozart", and hatched at the Terminal Tower in Cleveland, Ohio in 1999.  This is therefore likely his first attempt at establishing a breeding territory.  For a look at the nest site where Mozart was raised, and the latest news from Cleveland, visit the APK.net Falcon Cam.

Monday March 26, 2001
Marcel Gahbauer reports:  Great news - we can now confirm that there is a pair of peregrine falcons in downtown St. Catharines!  Furthermore, we have learned thanks to Barry Adams that the male is banded with a green band on the left leg, and a purple band on the right.  We are currently tracking down the information on this bird and hope to be able to provide details shortly.  The female appears to be unbanded.

The peregrine are being seen most often on the Corbloc building, at 80 King Street.  They perch at times on the window ledges, giving occupants of the offices an incredible view of the birds.  The female was also seen today atop the southeast corner of the Bell Canada building across the street.

Nadine Litwin, CPF's 1998 Hamilton coordinator, observed the two peregrines yesterday.  One was perched on the southwest corner of the Corbloc building, and the other on the southwest corner of an adjacent building; both had evidently just eaten as their crops were bulging considerably.  Looking east down King from the corner of King and Queen, both could be seen clearly.

We hope that this pair will choose to nest in St. Catharines this spring, and we will try to provide news about their activities as often as possible.  If you are in the area and see the peregrines, please email your observations and we will post them on this page.

Saturday March 24, 2001
Marcel Gahbauer reports:  Sightings along the Niagara escarpment have remained sporadic at best.  However, within the past two weeks I have received two independent reports of a pair of peregrine falcons in the "Corblock" area of downtown St. Catharines.  We are awaiting confirmation of the ID of these birds, but it sounds promising that southern Ontario may have a new nesting pair this year.  We look forward to providing more information shortly, and encourage anyone in the St. Catharines area to look for these birds and report any observations to us by email.

Wednesday January 17, 2001
Jim and Johanna Koolsbergen report:  For some time now, we have been watching, what looks like, a pair of adult peregrine falcons in the Niagara Region.  We have spotted the peregrines regularly at a location halfway-up the escarpment, as well as at a nearby quarry.

Marcel Gahbauer comments:  Due to the risk of disturbance at natural sites along the Niagara Escarpment, we are not disclosing the precise locations of such sightings.  Since the peregrine recovery in Ontario began, there has been only one successful nesting anywhere along the escarpment, so it is very important that the birds be given as much protection as possible.

I would encourage anyone visiting the Niagara peninsula to keep an eye open for peregrines, and to report these sightings to us.  Hopefully by receiving enough input we will be able to locate a nest site if one in fact does develop here, and we will then ensure that efforts are made to protect any such site from disturbance as much as possible.  Please email any reports of sightings to us.  Though we encourage observers to watch and document the peregrines as thoroughly as possible, do not under any circumstances take any actions which will disturb the peregrines, especially near a potential nest site.

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