Ringing Report 2021

The 2 Sheffield chicks (eyases*) were successfully ringed on Tuesday 18th May 2021, at exactly 21 days of age. (*A falcon chick is called an eyas)

As in previous years, the birds were checked over to assess their health and progress and ringed with a standard silver BTO ring and a bright orange “Darvic” coloured ring with a 3 letter code.

Then the birds were weighed and various (standard) measurements taken as happens all around the world when any bird is ringed.

Finally some DNA swabs were taken and some prey remains removed from the nest. The whole process took around an hour including the ascent & descent of the narrow, winding stair and slow climb up the ladder, one at a time, carrying all the climbing ropes, safety gear and ringing tools. The lights weren’t working on the way up the spiral stairs, just to add to the experience!

Ringing takes place under strict licenced conditions – Peregrine Falcons are afforded the highest possible protection under UK law, known as a Schedule 1 species – approaching the nest and ringing the chicks can only be performed by a Schedule 1 licence holder, who will have many years of skill and experience in order to gain such a licence. As ever the Sheffield Peregrine project is a voluntary collaboration between many people and we are indebted to Steve, Dean and Dan from Sorby Breck Ringing Group for donating their time and skills.

The two beautiful chicks are in great condition. As ever it is phenomenal to see how much they have grown in just 3 weeks. The size of their feet, talons, bills and even their eyes really stands out when seen up close – already looking purposeful and powerful. Their wings, of course, develop at a slower rate but, as the photo below shows, the wing and tail feathers have really started to push through quite rapidly in the 4 days or so prior to ringing. No longer are they solely white fluff balls. You can see the waxy sheaths which contain the feathers have emerged from beneath the down and the actual feathers themselvs are started to reveal themselves at the tips.

Hard to imagine the owner of this chunky bill was growing inside a small egg just 3 weeks ago!

Ringing is carried out at this point in the lives of the eyases precisley because their wings have yet to develop, so there’s no chance of them attempting to fly off when the ringers appear and falling from the tower. Conversely, their feet are pretty much full size by now (already!!) so the rings won’t become restrictive or outgrown.

Speaking of feet, you get a real impression of the size, sharpness and power of their talons. They really do look lethal! Note also the bumps and ridges on the underside which have evolved to help keep a good grip on prey in mid air.

Watching on the cameras, the chicks this year looked to be smaller than last years offspring in the first week and their progress appeared to be slower at first. So it was a surprise to find that both birds are actually bigger in almost every metric (tarsus length & depth, hind claw, bill to cere) than last year’s youngsters, although they are 1 day older at ringing than in 2020.

The birds from this day forward will now be affectionatly known as TTH and TXF! The bird ringed TTH weighed in at 650g and TXF 695g – good weights – but are they falcons (girls) or tiercels (boys)? Or is it one of each given the weight differences for 2 eyases hatched on the same day? Head ringer Steve has a great deal of experience ringing and measuring all sorts of birds of prey and advises that trying to conclude the sex of young Peregrines at just 21 days old from metrics alone is notoriously difficult – one of our birds (TXF) may be heavier than the other, but it is the lighter bird (TTH) which has a longer tarsus, gretaer tarsus depth and wider foot span – there speaks the voice of experience. There is no cut and dried clinching measuement in Peregrines to identify sex as there may be in other species, such as measuring the footspan of a Goshawk.

In will therefore be down to DNA analysis to determine the gender of the 2021 birds and DNA swabs were taken, as well as loose down, from both birds to this end. DNA analysis at the University of Sheffield will help to look into the genetic history of our birds and are more small first steps towards buidling a DNA database of the UK Peregrine population in order to learn more about their ecology. Hopefully this analysis will be quicker and more straightforward this year as, hopefully, the easing of Covid restrictions allows staff greater access to labs for research projects. The delayed DNA analysis of the 2020 St. Georges offspring has been carried out and the data is currently being verified – we’re hoping that we will be able to reveal the 2020 results soon in a forthcoming blog from Dr. Deborah Dawson. Fingers crossed.

The newly christened TTH and TXF (catchy eh?) were safely returned to the nest and the parents landed back within the hour after keeping a careful watch circling above. The eyases were fed in the early afternoon and Peregrine life had returned to normal. Peregrine’s aren’t daft though and there were some wary glances up towards the parapet of the tower looking out for strange men with ruck-sacks, hard hats and ropes.

A suspicious look from the lady.

We are grateful to Glenn, Chantel and Phil of the University of Sheffield Estates & Facilities team for arranging access to the tower and to Ian for managing the cameras.

Until next time….


Just a short blog tonight to confirm, for those who may have missed the comings & goings on the webcams and on the Twitter feed, that we have our first hatched chicks of 2021. Great news!

Proud Parents

The first egg was showing signs of breaking through, “pipping,” on Monday evening. By Tuesday morning we could see a reasonable hole in the egg shell when the falcon moved or shuffled and a few hours later a pure white fluffy chick was visible and free of its eggy surroundings. The birds continued to brood the eggs and keep the chick warm, offering glimpses when they moved or changed over but after a couple of hours it was apparent that there was not one but two little fluff balls just peeping out from beneath the brooding bird. The second chick must have been pecking its way out almost simultaneously with the first but just out of sight behind the platform side panel.

Small, vulnerable and pure white

Both chicks have been fed and look to be doing well so far. Tuesday was 32 days after the 4th/final egg was laid.

Pigeon for Lunch

It will be interesting to see if the remaining 2 eggs hatch. We’d expect that to happen in the next 24 hours. It doesn’t look too good for one of the them, which has had a broken shell for a while and the parents have been picking up and dropping down. So fingers crossed for the final egg.

Checking out the third egg.

Super Powers on St. George’s Day

Peregrines are admired for their physical prowess and aerial ability. The fastest creature on the planet. Refined by evolution into formidable apex predator. Fast, sleek, powerful, efficient. Razor sharp talons on the end of a locked tight grip. Incredible high definition eyesight. The ability to hunt, stalk, stoop, calculate the trajectory to intercept… all in a compact package. They are Masters of the skies. The Top Trumps of birds, some say the best bird on the planet*, but watching them on webcams reveals other amazing abilities – I just cannot help but be impressed by the patience and diligence required to sit and brood those eggs through to hatching.

For 36 days now she (and it mainly is the falcon) has been sat on one, then two, then three, then finally four eggs. She sits there day and night keping the eggs all tucked up and warm. She barely takes a break, swapping over with the male for only the briefest of moments to stretch her wings or go for a quick glide around the block. She’s never gone for much more than a handful of minutes. It’s remarkable. To be so patient and so dedicated. Do birds get bored? Who knows?! It matters not. It’s a feat of commitment.

OK so April has seen unseasonally low rainfall (for the second year in a row) and there’s been quite a bit of sunshine but the tower faces north, is umpteen feet high up and is open to the elements. The sun may be warm but its cold in the shade, at night it is still only hovering above freezing even as we approach May, the mornings are still frosty and we had at least 10 days of susatined northerly winds blowing down from the Acrtic. Yet still she sits there. Yes she’s not the only bird to do it. Whether a Blue Tit or an Eagle, they all have to sit and patiently brood, unless you’re a Cuckoo of course…. Nevertheless, for me, this dedication and patience, it’s a Peregrine Super Power right up there with all the others.

So what’s the state of play? Today is Friday 23rd April 2021, Saint George’s Day no less, and down at our very own St Georges it’s 36 days since egg 1 was laid and 28 days since egg 4. It’s still a guessing game as to when we will see an egg hatch but every minute now surely brings that moment closer. We might be waiting just hours, or days but surely no longer than a week. We are entering the red zone. Stand by your beds. This weekend is the time to keep your eyes glued to the Peregrines. Keep watching!

*Are Peregrines the best bird in the world? Kit Jewitt, creator of the award-winning nature BTO book ‘Red 67,’ certainly thinks so. Better known to some on Twitter as @YoloBirder, Kit has a Podcast series where he talks to other birders, conservationists, authors and TV presenters about their favourite birds and then measures them against his fave, the Peregrine. Named after the Peregrines bright yellow, and lethal, legs and feet, check out the “Golden Grenades” podcast via your favourite podcast app.

See BTO Red 67 here

Guessing Game

She sits, steadfast. Diligently brooding her clutch day and night, keeping her eggs warm so the chicks are able to develop inside. We hope the process goes smoothly and to nature’s plan. She has 4 eggs this year, laid between the 18th and 26th of March.

The standard incubation period for Sheffield Peregrines has been 31 or 32 days over the years. That is, in most years, the first egg has hatched either 31 or 32 days after the last egg was laid. Last year was an exception, we did not see a chick until 36 days had passed after the clutch was completed and to our surprise both eggs then hatched within a couple of hours of each other. As this is the only the 2nd year this female has bred we can only guess if it will be 36 days again? One thing which has become apparent over these recent years of well-watched urban Peregines is that no two Peregrines are exactly the same, they each appear to have their quirks.

As the final egg was laid on 26th March the key dates are therefore – Monday 26th April (31 days after last lay), Tuesday 27th April (32 days after last lay) and Saturday 1st May (36 days after). Mark them in your diary… and all the days in between! It looks like we have at least 7 days of waiting to go.

However, there may just be a but….

Unusually, as previously noted here, this year each egg has been brooded pretty much around-the-clock, ever since it was laid. Even the first egg, laid 18th March, was barely left unbrooded or unattended and never for more than a few short minutes. Could we be in for a surprise? Work those numbers again and 32 days from the 18th of March is….. (drum roll) TODAY! Perhaps this won’t be a slow week of watching a motionless falcon after all? Who knows? Predicting wildlife is a fools game but as each egg has several days of incubation ahead of the next I’d be surprsied if we see synchronised hatching as we did in 2020.

Now is not the time to look away. A fidgeting falcon and the first little white ball of fluff may not be too far off. Anyone for a sweepstake?

What next?

As I write this blog on Sunday evening we currently have 4 eggs. Will we get another? It’s not impossible but a Peregrine Falcon laying 3 or 4 eggs is much more common than 5 in the UK.

The eggs this year so far have been laid on a (very roughly) 60 hour cycle so that would mean a 5th egg would be due on Sunday evening 6pm (as I type!). Although the gap between eggs 3 and 4 was more like 62 hours.

Ordinarily, one of the key indicators that laying has finished, that the clutch is complete, is an obvious switch by the adults from brooding the eggs part-time to full-time. Generally it is normal for the first laid eggs to go unbrooded/uncovered for periods of time during the day, often 20-30 minutes at at time. Then, by instinct, the female will know when she’s laid her last egg and she will then keep the eggs warm full time. The male usually quickly cottons on to this too.

This behaviour switch will not be so apparent this year because, interestingly, our Falcon has been very diligently been brooding ever since laying her first egg on 18th March. There have been very few times when the eggs have been exposed to the elements for more than a minute or two. These eggs are being well looked after so far.

Last year both chicks hatched within a couple of hours of each other indicating very equal brooding times and the chicks developing inside the eggs at the same rate. Hatching this year may well be much more asynchronous given that egg 1 has been well brooded for 10 days already. Only time will tell.

If you are reading this on the evening of Monday 29th March (or after) and there’s no news of a 5th egg on this blog or on @SheffPeregrines Twitter account then its safe to say the clutch is complete.

One behaviour change you may have noticed already is hunting and prey provision. The Falcon has been doing the vast majority of the incubating and the Tiercel has therefore been placed in charge of providing her with food. As we know the Falcon is a prolific hunter and the vast majority of food items we see her bring back to the ledge are pigeons. In fact, compared to other sites around the country the Sheffield Peregrine diet is really quite boring, pigeon after pigeon with the odd Magpie or Gull every now and again. Not a surprise such a big, strong female prefers to take nice big dinners. The last 10 days though has seen a more varied diet now that the male is the sole hunter, with a couple of Blackbirds brought in and at least one Chaffinch. Keep your eyes peeled to see if this trend of a wider variety of smaller preys species continues if you can. Ed Drewitt down in Bristol is continuing to monitor the prey items taken into numerous Peregrine nests across across England – any prey items you see and can identify, or can get a screen grab of, or even just note the time of, please tweet @SheffPeregrines so details can be passed on to Ed. The Wakefield Peregrines were observed bringing in a Crossbill to their nest a couple of days ago, the first time this species has been recorded on a UK PeregrineCam. We are learning all the time.

One other change from the 29th, affecting people not Peregrines, is the “stay at home” advice ends and changes to “stay local.” This blog makes no comment on how clear these rules are or how they should be interpreted. The changes may mean some people now feel able to visit St. George’s to view the birds. If doing so please respect other people in the area, maintain 2 metre distance at all times and observe the rule of six to maintain the good reputation of Peregrine enthusiasts. The land at St Georges is unversity property so please observe any instructions given by uni staff if they happen to be on site.

Egg Four

Just a quick note to confirm that a fourth egg was laid on Friday morning as had been hoped and anticipated. It took a while to be able to confirm it though!

Eagle-eyed observer Sue saw what she thought was egg laying activity just before 6am and tweeted to let everybody know. Later Alan was able to review and tweet video of the action – it is worth a look/ if you get a chance! Clearly laying a large, hard-shelled object is not the most comfortable experience and after what looked like the laying event the Falcon toppled over, almost doing a forward role! She certainly seemed startled! The bird recovered quickly and was back down onto the clutch immediately.

Throughout all this action no eggs could be seen so the evidence of a new egg was only circumstantial. When the first leg-stretch/changeover of the day came at 6.30am the clutch was partially obscured behind the side of the platform and to all intents and purposes looked like there were only 3 eggs.

Despite lots of eyes watching the birds all day a visual sighting of 4 eggs together proved impossible – the eggs spent most of the day under incubating parents, mainly the female. When we did get a glimpse only 3 could be seen. I was beginning to doubt there was a 4th egg! Maybe we had jumped to the wrong conclusion?

Eventually, on Saturday afternoon, over 24 hours after the “lay,” Alan managed to tweet a screen grab showing 4 brown shapes rather than 3 – confirmation we weren’t imagining things!

That we did eventually get 4 eggs in sight is a good sign that the eggs are being moved around a little by the birds as they brood them which hopefully means they are all kept equally warm and will therefore all develop at the same rate.

It would seem safe to assume the reason why the Falcon chooses to lay her eggs tucked up at the right hand side of the platform and partially out of sight – here she gets most protection fron the prevailing westerly winds and has the best chance of keeping the clutch warm …and boy were those winds cold on Saturday morning with a dusting of snow in the nearby western suburbs of Sheffield.

Bright but chilly Saturday morning captured by @jilliano

Unfortunately that does mean we have a bit of a blind spot when it comes to seeing egg laying and hatching. Long term that issue is one which could be addressed when the time comes to upgrade/replace the cameras – which will inevitably have to happen at some point in the future as the cameras age. One of the purposes of the Sheffield Peregrines Virgin MoneyGiving fundraiser would be to contribute towards improved cameras as well as funding further DNA study. Please do consider making a donation, however small, if you can. Follow the link at the top right of this page.

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and then there were three…

A third egg has been laid this afternoon. So far this month we’ve had the earliest egg ever and the clutch is now bigger than last year’s. Will we get a 4th egg? Maybe, maybe not. We’ll know by Thursday evening or Friday morning. The Falcon is on roughly a 58-60 hour cycle between eggs. My money is on 2am Friday morning. Anybody fancy staying up to watch?

Egg 2

The second egg was laid some time overnight on Saturday night/Sunday morning and was revealed on camera at breakfast time. Two eggs equals last years complete clutch, will we get more this year? I would expect so. A clutch of 3, 4 and sometimes 5 eggs is typical.

The Eggs do not get incubated full time until the clutch is complete so don’t be alarmed if there’s no bird sat on the eggs sometimes. The adults have been very diligent so far and usually there’s an adult sat keeping them warm.

If there’s to be another egg Tuesday 23rd should be the day it arrives.


The first egg of 2021 was laid around dinner time this evening, Thursday 18th March. Somewhat earlier than expected, given last years first lay date was 29th March.

This is fantastic news. This is the earliest ever recorded egg at St. George’s. Peregrines have bred on the tower since 2012 and we have records of first lay dates from 2013. The previous early record was 19th March in 2015 & 2016. So we’ve beaten that by one day. Eggs are beggining to be laid at Peregrine sites across the UK now in the last week. It’s nice to be amongst the early starters.

Peregrines typically will lay an egg approximately every 48 hours until the clutch is complete. If all is going to plan we should expect another egg perhaps on Saturday evening, it could be a little sooner or a bit later. Last year there was a gap of almost 72 hours between egg 1 and egg 2, which were the only eggs laid.

The first glimpse of the egg shortly before darkness fell.

The Falcon sleeps as she broods her egg tonight and keeps it warm.