Hi there Peregrine watchers! Happy Monday to you all.
Let’s start off the week with a nice photo of TRF showing a rare glimpse of his leg ring. It’s much harder to catch sight of it on the webcams this year compared to last. Regular watchers will have noticed how his appearance has changed subtley since the 2023 breeding season and his winter moult has shed any last vestiges of his juvenile plumage. It would appear that his latest set of feathers cover his legs much more than was the case previously and the colour ring stays out of sight much of the time. Fortunately, this year’s plumage also seems to have provided us with a handy white spot on his crown which helps us to continue to be able to identify him quickly on camera.
Anyway on to the main event: Tucked away underneath the warming body of an adult bird the four eggs are nearing the end of their incubation. Inside each should hopefully be and almost fully formed chick. Our Peregrine eggs generally take around 31 or 32 days to hatch, when measuring from the date the clutch was completed. This would make the likely hatch date to be Wednesday or Thursday of this week. Exciting!
However, this is not set in stone. We’ve had years in recent times where eggs have taken 33 days and even 36 days before the 1st hatching, these were years where there was either some disturbance around the site or a bit of cold snap. Hopefully not significant coinsiderations this year.*
Occasionally UK Peregrine eggs elsewhere have been recorded to hatch after a shorter incubation of 29/30 days, if we take this into account and add in the observations mentioned in our previous blog [this clutch has been well incubated since Egg 2 was laid] it’s probably worth watching the webcams very closely from now onwards. One way or another we should see some activity this week.
Lookout for the adult birds shuffling about when the eggs are underneath them or watch for them staring at, or listening to, the clutch, particularly on a changeover. Once the birds appear a bit more interested in the eggs rather than nibbling at gravel (!) it’s worth assuming that they sense something may be about to happen.
With typical bad luck, I myself will be out of town and away from a computer on Wednesday and Thursday when the first egg is anticpated to hatch so more than ever we need you all to keep watching the webcams! Please share any notable sightings with the Sheffield peregrines Twitter account or the SBSG Facebook page.
*Disclaimer: While the excitement surrounding the hatching is palpable, it’s essential to remember that the natural process may not adhere precisely to our predicted schedule!
After the excitment of our earliest ever Egg1 lay date, Egg 2 arrived 59 hours later as previously documented. Fast Forward another 59 hours and Egg 3 arrived on March 22nd and the clutch was completed when Egg 4 arrived at (we think) 16.51 on March 24th. This is our earliest ever clutch complete date by 2 whole days, surpassing the site’s previous early date (26th March in both 2016 and 2021). With egg intervals of 59, 59 and 58 hours this falcon has been almost metronomic in her timing, which in all likelihood indicates a fit, healthy bird who is in good breeding condition and living reasonably stress free, content with her partnership, her food supply and her environment. The minimum interval between Peregrine eggs is generally acknowledged to be 55 hours so this years productivity is not far short of perfect.
Falcon on eggs 19/4/24 (all screenshots by Jill Greenwood)
It took a while for the 4th egg to be sighted on camera as the clutch was well sheltered behind the “western wall” of the platform….. but confirmed it eventually was and the birds settled down to the long and patient business of a month of incubation.
Four eggs in sight, just!
Just like the laying, incubation has, so far (never count your chicks before they hatch!) gone like clockwork. Exactly the unremarkable, largely uneventful, period we wish it to be. Pray that continues into next week and then the excitement levels will begin to rise! It will be interesting to see whether all 4 eggs hatch (if all continues to go well) – we have only ever had 4 eggs hatch on 2 previous occasions – 2014 & 2022. More often than not an unhatched egg remains. As a rule of thumb Peregrines tend to start full-on, round-the-clock incubation of the eggs once the third one has been laid (in a clutch of 4) – a mechanism which many species employ to ensure the eggs all hatch closely together.**
The risk to this strategy is that, unlike Blue Tits or Treecreepers etc, who’s nest may be tucked away in a tree trunk or nest box and ensconced in a feather-lined or wool-lined nest, an open Peregrine nest high up on a cliff or a roof or a platform can be exposed to the elements. Wind, rain and snow can potentially pose a challenge to eggs one and two if they are not incubated all of the time and in years where one egg fails to hatch, there’s often speculation that this could be the first laid egg. Of course as they all have similar coloration & marking (and get moved and turned for 31/32 days) there is no way of keeping track of which egg is which, so we cannot know if there’s any truth to this theory.
However, this year our birds have been on top form and, from my viewing, it’s hard to argue that this clutch has been very well incubated almost from the word go, and definitely from Egg 2 onwards. Combine this with the speedy, punctual laying and you never know…. maybe 2024 could be a good year for a full house?? The incubating birds have had to put up with a fair bit of rain but up until this week’s biting northwesterly wind arrived, temperatures have not been too bad – we haven’t seen incubating Peregrines covered in snow this year for once! Intriguing propsects….
Changeover time
The other big thing of note this year is the amount of incubating the male has been allowed to share in. He really has fully played his part. Last year the falcon was very reluctant to let the male near the eggs at all and was openly hostile, despite his apparent keen-ness. Given how inexperienced and clumsy he acted around the clutch in 2023 webcam watchers could concur with the falcon’s thinking! This year however, he looks far more assured and confident, this has been a pair working in complete harmony. He’s done a great job keeping the eggs covered although it’s always clear to see on a changeover just how much harder it is for the smaller male to get all of the eggs under his body compared to when the falcon sits back down. Watch the cameras and take a look – the next 5 or 6 days may be your last chance for incubation watching this year.
Carefully covering 4 eggs
There has been intruding birds visiting the area a handful of times but they’ve each time been seen off by one or both birds very quickly and, so far, touch wood, there’s been no dramas. Although it’s always a heart-in-the-mouth moment if they both dive after an intruder and the eggs are left uncovered.
I may write a little more about intruders in a later blog…. once the danger period has passed, I don’t wish to jinx anything at the moment! We Peregrine watchers don’t want any sort of drama, conflict or disruption when eggs are close to hatching nor when there’s tiny new chicks around.
There’ll be another post here on Sunday or Monday in anticipation of an interesting week. Watch this space.
Male incubating. Note the little white dot of feather on his crown – helps to identify him!
**The Sheffield Peregrine clutches have been fairly synchronous in hatching over the years with the viable eggs often all hatching within 24 hours of the first, a far shorter period than the 7 to 10 days which they have been laid over. Not quite on Blue Tit level where they’ll all hatch within a few hours of each other but nonetheless generally synchronous. However, some species, e.g. Barn Owl, will incubate immediately the first egg is laid then keep on laying. Given that each egg requires the same incubation period, providing there are constant temperatures, the eggs in these species then hatch asynchronously and the hatching intervals more closely match the laying intervals – days apart. In this situation, early eggs are not allowed to stay dormant or chill in the way that they might in synchronous hatching birds but the downside is that there can be large size differences between the oldest and youngest chicks and the unequal competition that creates when it comes to each chick getting enough food to survive and grow.
The Falcon laid her second egg this evening (Tuesday) around or just after 9pm. That’s roughly 59 hours between egg 1 and egg 2. Last year the interval between eggs 1 & 2 was an even more rapid 55 hours, nevertheless it all seems to be happening very quickly this year.
As ever Alan @doggie 3132 was on hand to grab a screenshot. I do love a night time egg lay. The black and white adds a bit of atmosphere to the scene. Good job she allowed both eggs to peep out…. just.
And whilst we’re on the subject of new arrivals, this year we’re being helped out with the webcam watching by Theo Hunter. Theo is an undergrad at the University of Sheffield Animal & Plant Sciences department and is dedicating some of his time every day to help watch the Peregrines. Welcome on board Theo and thanks for all your work so far.
Fingers crossed all goes well this week. If Mrs P keeps up her current pace, egg number 3 is due some time on Friday morning. But don’t be surprised if it takes a little longer, Jill captured this image of a rather tired looking Falcon just after she had laid.
Keep watching and chat with us on Twitter @sheffperegrines and @shefbirdstudy
Hello there Peregrine Watchers. The breeding season has begun!
There has been some good courtship and copulation attempts witnessed on camera since late February but I don’t think any of us thought we’d quite reached peak copulation activity just yet. Yet lo and behold out popped an egg around 10am on Sunday 17th March.
We can’t be sure of the exact time of laying because, true to form, our girl is once again using the sheltered western corner of the nest platform where the camera can’t quite see. It’s a smart choice weather wise so who are we to complain. This is the current falcon’s 5th breeding season here at St. Georges so she knows what she’s doing
17th March makes it our earliest ever Peregrine egg at St.Georges by 24 hours. The previous earliest was on the 18th March 2021 which was her second breeding season. The previous falcon’s earliest lay dates were 19th March (2015 & 2016) and 20th March (2014 & 2017)
This years first egg is a full eleven days earlier than last year but perhaps shouldn’t be a complete surprise. After a mild (but very wet) winter here in the UK, some branches of the bird world appear to be off to an early start – there’s been some very early Osprey arrivals at sites with well-watched webcams and Thursday last week seemed to herald the first notable waves of Sand Martins and Chiffchaffs hit our shores, along with the odd House Martin and Swallow.
It is all systems go from here on in! Get down to your local park or woods and listen for Chiffchaffs or visit your nearest water body to check for Sand Martins and Little Ringed Plovers… but don’t look away from the Sheffield Peregrines webcams too long! Stay sharp and keep watching for the second egg – my money is on 5pm tomorrow (Tues 19th). Let us know via Twitter if you spot anything, tag @sheffperegrines and @shefbirdstudy
The fourth, unhatched, egg from the 2023 clutch was recovered by Sarah whilst the chicks were being ringed and measured. It was passed on to Dr Nicola Hemmings for examination and analysis.
Dr. Hemmings is based within the University of Sheffield School of Biosciences and is a Royal Society Dorothy Hodgkin Research Fellow. Her research focuses on how and why animals vary in their ability to reproduce, with particular focus on the causes of infertility and embryo death.
In contrast to other unhatched St George’s eggs which Dr Hemmings has analysed in previous years, this embryo was much further developed and well-formed. So it appears that this egg was progressing nicely along with the others until something changed. Nicola’s summary states “the embryo itself looked to be in good condition with no obvious reason for premature death.” Also in contrast to previous, the egg was not rotten or foul-smelling.
When examining failed eggs, Dr Hemmings determines which development stage an embryo has reached. To do this, Dr Hemmings has compared our egg’s development to known and documented development stages of other avian embyros, including the closest known raptor species*, and adjusted it to take into account the known (slightly different) incubation period of Peregrines – generally 30 – 32 days at St Georges. Dr. Hemmings concludes that the embryo was a minimum of 20 days old and most likely 21 or 22 days old.
*At this time there is no published Peregrine-specific staging series available to judge this embryo against.
As there’s no physical cause of death apparent it is worth considering an external cause of death, physical or environmental. If the egg was developing at the same rate as the successfully hatched eggs then the embryo died in the last few days of April. Looking back at weather charts, nothing too extreme occurred with conditions fairly benign with rainfall well below average and certainly no snow like there has been in a couple of previous incubation periods!
Remember the snowy incubation in April 2017?!
Temperatures were about average or just below average for the time of year with highs of between 8 – 14 ºC, winds were weak although it’s worth noting that they were from a cool North and NNW direction and temperatures did dip to -1 and -2ºC in the early hours of the Tuesday 25th. Perhaps an egg wasn’t quite covered up overnight? It’s pure speculation. There’s nothing untoward reported around that time from time from regular Peregrine watchers and they were well-watched over the period.
An alternative theory from Dr Hemmings is thrown up by the eggs being hidden from view during the laying period and a good while thereafter…. “If for some odd reason, egg 4 was laid extremely late, and therefore developed with a ~10 day lag behind its siblings, dying once they started to hatch due to disturbed incubation. This might also explain why the egg seemed relatively fresh and non-smelly/rotten – it wasn’t actually dead in the nest for that long. It’s unlikely that there was such a large laying interval, but it’s not unheard of…”
I guess we’ll never know. However, we only ever find anything out by observation, enquiry and research. Work in fertlity is important, and can be particularly so in relation to endangered species where every new born counts. By looking at unhatched egg contents, scientists such as Dr Hemmings can diagnose fertility problems (i.e. insufficient sperm), detect egg infections, and identify abnormalities in developing embryos that may be linked to genetic problems or environmental factors. Understanding these causes of hatching failure allows rapid and effective measures to be put in place to improve success in the next breeding season.
You can read Dr Hemmings’ previous blog on our unhatched Peregrine eggs, which goes into greater depth, here.
June was a good month for the Sheffield Peregrines blog. We received 7127 visits to the site from 2743 visitors. Thanks to all our readers for interacting with us. Please keep sharing, liking and commenting to spread the Peregrine word around!
Sunday 18th was only a couple of hours older when reports came in just after midday the XA7 had departed the box, again in an unconvincing manner.
An hour of searching the churchyard and the alleys and backyards of Portobello was fruitless and the Falcon on the side of the church was unperturbed, leading to suspicions XA7 had made it to a nearby roof.
With X76 still on the roof, female X46 was the only chick left visible in the nest platform and on camera.
But by Wednesday morning all three chicks were safely back on the nest platform. XA7 had made it back under her own steam. A bona-fide fledge. No doubt about it.
Where she’d been came to light a few days later when video emerged on a local Facebook group. She’d flown or glided north, down the hill to Kelham Island on the Sunday lunchtime and was seen scurrying around on the pavements of the public spaces. She fortunately managed to avoid the local cats and dogs and build up her flying skills sufficiently to make it all the way back up the hill and to the top of the tower. An adventure indeed.
Thanks to Michel Hawat for sharing these photos and a wee video too which we’ll post on Twitter.
Unfortunately we’re not sure exactly when X46 fledged because thankfully it seemed to be uneventful. Waiting until she was properly ready and strong was clearly a sensible policy. But with some human assistance and a dollop of good luck, all 3 birds are now flying around well. They have been spotted on the Arts Tower and Hallamshire hospital as well as the church tower and have been receiveing hunting lessons and a varied diet which has included Great Spotted Woodpecker and Common Swift.
After X76’s Friday night adventures, Saturday 17th passed off without further incident until, just about the same time as the previous evening, reports surfaced on Twitter of an unusual bird of prey sitting on a bin in the courtyard of city centre student accommodation! We were just sitting down for dinner with friends in a Manchester curry house – great timing! A picture on Twitter confirmed it was indeed a young Peregrine – our mate X76 again. Some kids just don’t learn!
using one claw to hang on to the bin lid handle!
Despite best efforts, no response came to requests for a precise location and contact details. Students being students, they’d headed out for the night….
It was a bit (a lot!) of a worry because it was a night of violent thunderstorms but by morning we had a contact name, a location and confirmation that the bird was still there in a courtyard, further down the hill from the church, which wasn’t publicly accessible. Many thanks go to Adam Young (@adamyoung91) for reporting and the very helpful warden and staff of Rockingham House student halls.
X76 was swiftly scooped up by ringer Luke Nelson (@luke_nelso) and once again deposited on the roof of the tower. He’d toughed out the storms sat on first the metal bin lid and then, more wisely when lightning’s about, on a wooden park bench!
Nobody saw X76 take to the air, although he did make it more than twice as far this time. He hadn’t been seen on camera since his Friday night escapade. Maybe he tried to make the leap from the roof to the ledge and overshot. Who knows? One things for sure, he’s not shy and he’s got a sense of adventure.
First fledge? We’ll never know for sure.
Being early in the day, this wasn’t the last we heard from our juvenile Peregrines.
If it’s merely a matter of leaving the nest then all it takes is a hop onto the church ledge. Not much of a milestone. Hardly one worthy of it’s very own verb.
And what counts as a first flight? Surely there has to be some intention to take to the wing? A decision to leave. A leap?
Early on Fri 16th the birds were nice and quiet and calm. Looked like they were staying put!
The first of the 2023 chicks to leave the nest was, perhaps slightly surprisingly, X76 the smallest and sole male. He departed the nest early evening on Friday 16th June and ended up on the ground at Jessops West on the University campus, only perhaps 100m from his starting point. There’s no photographic evidence unfortunately, however webcam watchers at the time report that he didn’t so much make a bold leap but rather lost his footing and disappeared out of sight out of the bottom of the screen.
Going on the average time between eggs hatching and first flights from our previous years, 16th June was indeed the predicted date for a “fledge” or first flight. Having spent the previous couple of days avidly scrutinising the young birds development, I had however been praying that a first flight attempt would not occur as scheduled. The birds were clearly less well developed than they were last year at the same age, more white down still lingering and feathers slightly less well developed. Moreover, behaviour wise they simply had not done enough wing flapping and exercising to be ready for powered flight. They just weren’t active or curious enough, regular watchers can usually see when they’re approaching being ready. I was keeping fingers crossed they’d all wait until Sunday or Monday to be a bit more like ready. Meanwhile, across England, particularly down south, pictures were being posted of urban birds successfully taking intentional, powered, first flights and returning to perch.
Running up to his departure, X76 was very fond of perching on the edge of the box closest to the camera, a handsome wee chap! But it was his sisters who were a bit more adventurous hopping on and off the perch and ledge. I’d expected one of them to go first but that wasn’t the case.
X76 was rounded up by the ever reliable Calvin on the University security team (@CalvinKarpenko) and kept quiet until Jill and I arrived to take him up to the roof of the tower. He may have looked sweet on the webcams but he was a feisty wee sole and very ready to defend himself. Although he was very well behaved once safely placed into my rucksack.
Climbing a ladder with a Peregrine on your back, just your average Friday evening in June! X76 showed his appreciation with a series of filthy looks and hisses as I left him on the roof to make his own way back to his siblings. I can confirm his talons are razor sharp and that he has a very good grip.
Does falling off the tower sideways and then gliding down to the floor really count as fledging? I’m sorry lad, you’re going to have to try harder than that!
If you haven’t done so already, click on the link to the Webcams at the top of the blog and check out the new Sheffield Peregrines Webcams page. We hope you like it. Our lovely friends in the University of Sheffield IT dept have updated the page for necessary back-office and security reasons and it is now hosted in a different location. Hence the layout change.
The move introduces a couple of welcome changes, including having the ability to have both cameras on the same page and being able to play them both at the same time too. No need to switch, just scroll down. On certain devices like tablets you are able to watch both cameras play simultaneously. Or you can run both cameras in separate browser tabs and quickly switch between the two.
Everything else remains the same and the existing web address directs you to the cameras – no need for viewers to make any changes.
The system was tested as a Beta for a few weeks and so we know it works with most device, OS and browser combinations. However, there does seem to be an issue with Firefox on Mac OS desktop. If you are on this combination, the individual cameras can be viewed when you click on the link but they don’t load properly on ther home page. If you do have any issues just try a different browser e.g. Safari on Mac OS works perfectly.
Another blog soon detailing those tricky first flights….
The young birds are becoming more adventurous by the day. If you do wish to see all 3 together, we suggest you make a trip down to St. Georges soon!
Sheffield Peregrines 