Month: May 2020

Ringing the Chicks

On Weds 27th May 2020 the two Sheffield Peregrine chicks were ringed, measured and checked over by a team of experienced and licensed bird ringers.  The team made the precarious journey up the narrow winding steps and vertiginous ladder inside the church tower before emerging onto the roof and using climbing equipment step over the parapet to collect the chicks from the nest.


I am happy to report that both chicks look fit and well and are developing nicely.  They seem so much bigger in the flesh than they do on the webcam and also look much stronger and far less vulnerable.  It’s hard to believe they are not quite 3 weeks old yet!   The chicks were bright eyed, well behaved and occasionally vocal but not alarmingly so.  You can already see their primary  feathers coming through on trailing edges of their wings.  As you can see from the image below the black tips are already showing although most of the feather is still in its waxy protective sheath.


The birds are checked over and, as stated, look in good, normal health.  Ringers Amy and Dean who handled each bird could feel that they had full crops and bellies – they fed on Pigeon and Starling the day before so that’s not surprising!  The parents are feeding them well, and with only two mouths competing at mealtimes there’s obviously plenty to go round.



As well as confirming the chicks are healthy the purpose of ringing the chicks is to monitor survival rates and collect information about their movements.  Standard ringing tells us information if the bird is re-trapped (in mist nets for example) or if the bird is found dead.  This is fine for small birds which can be readily trapped and tracked during their lives but that’s bot so easy with birds of prey!  This is particularly pertinent to the Sheffield Peregrines: despite both of our adult birds wearing a standard silver BTO ring, nobody has ever obtained a close and clear enough image to read a number.  Therefore we know nothing about where they came from or how old they are.  This is where the more recent technique of colour rings comes in.


Today the Sheffield chicks have each been given a standard silver ring (or band as they are called in many other countries.)  Additionally they have been given large colour ring (also known as a darvic ring.)  These bright orange rings have a large 3 letter code which is much easier to read through binoculars or on photographs.  These big bright rings have been used on many birds of prey, perhaps most notably on Ospreys.  It enables birds to be more easily tracked, by multiple observers (any birder with binoculars or a camera not just scientists or trained ringers) throughout their lives, throughout their range and without the need for recapture.  Or death.  On Peregrines here in the north of England darvic rings have allowed us to learn that a 2018 Sheffield youngster (colour ring PSA) spent some of its first winter time in the Dearne Valley and the orange darvic ring “PRF”  identified a dead Peregrine found last year on a Sheffield City Centre roof as one of our 2017 offspring.  Sadly, just this last week, a darvic ring helped to identify an illegally killed Peregrine (found suspected shot in Brighouse) as one born at Leeds University in 2018.  More details on that here


As you can see from the photo our two chicks can now be identified as TRF and TNF.  TRF carries the BTO silver ring GV53849 and TNF carries the ring GV53850.


Various metrics were taken.  The birds had identical wings lengths of 147mm and both are very similar weights coming in just under 600g.  The length, width & depth of the Tarsus is measured* as is the length of the Hind Claw, the middle toe and the distance from the Bill to Cere.  From the information gathered TNF is ever so slightly bigger on 5 of the eight measurements but there’s not much in it.

* the Tarsometatarsus is a bone only found in the lower leg of birds, it’s a fusion of bones which is, in layman terms, equivalent to out ankle and foot (metatarsal) bones.  The easiest way to remember it is that it’s the part of the birds body which the rings go around  – i.e. the part often mistakenly identified as the bird’s leg.


The burning question on many lips is of course ‘What sex are the birds?’  Unfortunately we are unable to answer that questions currently from the metrics taken.  There’s no notable size difference so we can’t make any “guesstimates” that one is female and the other is male.  It’s a distinct possibility that both these Eyases are the same sex.  Due to not having chicks to ring in 2019 the last comparable data is the 3 chicks ringed in 2018.  The measurements that year showed one bird with significantly bigger measurements than the other two which led to an assumption that at least one of the birds was a female.  The three 2018 birds weighed 517, 581 and 620 grams was meaning there over 100g difference between the biggest and smallest bird.  There’s nothing so obvious this year as the birds weigh 584g (TRF) and 598g (TNF).  We cannot compare the birds between the years as the 2020 birds have been measured a couple of days later (Covid-19 related) than 2018 and of course the fact that there’s only 2 of them could mean they grow at greater rate anyway.


The only way to determine the sex of the 2019 Peregrines will be through DNA analysis.  As their feathers are now coming through the chicks are shedding down and samples of this were retained for this process.  Adult flight feathers and discarded pellets were collected from the nest platform.  Dr Deborah Dawson at the University of Sheffield Molecular Ecology Laboratory will examine the samples to determine the sex of the chicks and to try to discern any information we can about our adult birds, particularly the “new” female.


This blog will of course keep you posted of any findings as and when they are available later in the year.


As well as the usual risk assessments and safety measures taken by the ringing team  in any regular year,  this year the process was undertaken incorporating measures relating to Covid-19, social distancing and reducing the risk of any infection.  On the ascent/descent of the tower and up on the tower roof  2 metre distancing was observed by team members with the two members of the team who did have to work side-by-side being members of the same household.  The team where therefore able to observe social distancing without introducing any elements to the process which slowed things down or endangered the birds.  The birds where ringed under the necessary permits and licences required for ringing Schedule 1 protected species such as Peregrines.


Many thanks to everybody involved in the process of ringing the birds and making this possible whilst working from, not having the usual access to systems, staff and keys and whilst having to deal with the extra Covid-19 workload.  Thanks to Steve, Amy, Dean and Sorby Breck Ringing Group, to Jill and Martin who marshalled at ground level, to Glen and all the University Estates staff for facilitating and to Deborah and Phil for co-ordinating the effort.


The chicks were safely returned to the nest platform where we found them (out of the webcam shot – as per usual in 2019) and we stayed St. Georges until an adult bird returned to land.  As Alan pointed out on Twitter the adult female kept peering apprehensively up at the parapet were the ringers had appeared from.  The former intruder is wary of intruder’s herself but she has settled down this afternoon into a normal routine.


Peregrine Diet Study – Update

In February we asked for your help on a study led by Ed Drewitt ( on the seasonality and diversity of Peregrine diet and the distances they travel.   Ed has now compiled the first draft Sheffield Peregrine prey list from webcam images kindly tweeted by @SheffPeregrines followers since 6th Feb.  Thanks to all who have contributed so far, especially Alan @doggie3132 and Wendy Scott @Wendspix1 and Alistair McMillan @AlMcM   Keep them coming!

Male Bullfinch (photo Chris Greenwood)

Seven prey species have been recorded so far during this study period:
Blackbird  (male)
Bullfinch (once, male)
Feral pigeon
Goldfinch (once)
Great Tit*  (at least 4 including 1 recent fledgling)
Teal (once)
In addition we could safely add Wood Pigeon as I’ve seen a few of those brought to the nest over the years of webcam watching (although I have made a note of dates previously).
*Wakefield Peregrines group have been formally recording a lot longer and have approx 50 prey species – their excellent page summarising this is at  but, perhaps surprisingly, they dont have Great Tit on their list yet!



Great Tit (Chris Greenwood)

A video of the male Bullfinch being brought into the platform on 11th May 2020 can be seen on Alan’s YouTube Channel here
The Eurasion Teal is an interesting record.  The most common and familiar duck by far in the Sheffield area is of course the Mallard, the resident of practically every park in Britain. There are plenty of Mallards available close by to the Peregrines on the River Don or at Crookes Valley Park for example.  A Mallard would make a nice big and relatively slow-moving target for a Peregrine to attack and a frequent sight over the city, yet we’ve never seen one taken here in Sheffield and I’m not aware of one been taken anywhere else. (Ed may set me straight on this!)  We can perhaps assume that Mallards and the many other similar sized UK ducks are too big and heavy for even a female Peregrine to carry back to a nest site.  Teal however is the smallest duck to reside in or visit Britain and perhaps that’s what sealed the fate of the one captured on 15th March.

Eurasian Teal (Chris Greenwood)

Teal are not a common sight in the very centre of Sheffield but can be seen on the River Don from time to time and more commonly at sites such as Forge Dam and Orgreave Lagoons which are still well with the urban area.  The captured bird may well have been in transit between such sites.
BTO scientist Dr. Esther F Kettel came to speak to Sheffield Bird Study Group in 2017 about her fascinating PhD work towards a study comparing the breeding success urban and rural UK Peregrines.  Esther quoted evidence in her research of Peregrines taking birds up to 500g.  At an average weight of 360g Teal perhaps represent an excellent combination of size of target,  weight to carry back to eyrie and size of reward when it comes to mealtime.  Conversely a Mallard can weight from 750g – 1.5Kg.  Teal is noted as a frequent prey species at Wakefield.
At her fascinating talk Esther spoke about birds such as Water Rail, Moorhen, Little Grebe, and even Corncrake remains at urban Peregrine nests.  Such species most typically move at night both locally and/or on long-distance migration and were surprise discoveries to ornithologists.  Esther put forward the proposition that one of the contributing factors to the phenomenon of successful urban Peregrine pairs is that the artificial lights of our cities enable the birds to hunt at night, possibly by picking out the silhouettes of the birds against the light pollution.  It represents phenomenal adaptation and opportunism on the part of the Peregrines, I mean, Corncrakes are rare enough in their preferred habitat in Scotland’s western fringes, they’re hardly known for being sighted in the downtown metropolis!

A Goldfinch was brought in on 4/4/20 (Chris Greenwood)

There is so much more to learn and you can help.  Ed’s research has the potential to tell us more and more about urban Peregrines. It would be great to document and expand the Sheffield prey list further.   If you want to help record peregrine prey.  Record the image by doing a screenshot or video and tweet it to @SheffPeregrines  and @eddrewitt

The date and time are shown on the bottom left of the webcam image – please be careful it isn’t cut off if during any image cropping.
There are numerous guides online about how to screenshot part of your screen for both Apple Mac and the various versions of Windows.  A quick search should find you some instructions.  Video is a little more complicated in that you may need to download a small piece of software but these are often freeware or share ware.  Apple users can Screen Record via the included Quicktime application.  Quicktime is also available for free for Windows but there may well be other better options.
Bird lovers are taking part across the UK and perhaps my favourite/most gruesome record so far is of  an Avocet taken way back in February by Dorking Peregrines, picture kindly supplied with permission from @sophiedorman33
Get involved!
22/5/20 Chris Greenwood and Deborah Dawson

Doubling Up

Screenshot 2020-05-12 at 16.11.49

5 days old now and the chicks look to have almost doubled in size already.  They’re still amusingly unsteady and wobbly, like they are controlled by a puppeteer’s strings, but rapid growth is a good sign.  It must have been chilly up there the last 36 hours or so – the bigger the birds get, the better they will be able to handle any cold they are exposed to.  However, most of the time they are still tucked under a brooding adult for warmth and feeding time is the only time to get a proper look at them.  It’s great to see them when they are out on show and this post is basically just an excuse to post some cute screen grabs of them!  They’re adorable.

Stay strong little eyases.

Screenshot 2020-05-12 at 16.15.45


They’re under there somewhere


We have hatched!

Having the eggs tucked away mostly out of sight hasn’t really helped anxiety levels or given us much to go on but it looks like both eggs hatched between 4 and 7am this morning (7/5/20).

The brooding bird was eating from a broken egg shell around 4.30am indicating it had hatched. When the bird shuffled around to remove a half shell from beneath her we caught a glimpse of a fluffy white chick and the other egg, still looking intact. The brooding bird (probably the Falcon) did not want to hand over brooding duties when the partner returned to the box, even though it had been called over. All of this happened in the dark on the night vision cam. The egg shell was removed at some point. More shuffling round, this time in colour, after dawn, revealed the second egg was gone and what looked like a second ball of white fluff. It’s still hard to see because the birds are so tucked behind the side wall and hopefully being kept warm and secure under the adult’s body and wings.

It’s 37 days since the 2nd egg was laid. The longest incubation period in the history of Sheffield Peregrines. Which is an interesting stat to remember given that this is a new female. Previous years either the previous Falcon saw 31 or 32 day incubation typically, through wind snow and rain. The weather this year was generally warm and very dry with no snow, although the clear nights have been cold at times. If this tell us anything it surely indicates how warm eggs can be kept under a Peregrine even when it is covered in snow! It will be interesting to see if 37 becomes the new standard incubation period at St George’s. But all that’s a long way off yet….


The rest of today is critical. The adults need to bring in a kill and get a first feed into the chicks to give them a healthy start. A feed should also give us a much better glimpse of the chicks to assess their size and demeanour.

The weather is on our side. It’s warm, calm and dry. The adult looks attentive and content. Let’s hope the day goes smoothly.



Screen Shot 2020-05-02 at 17.07.53

With any luck the waiting is almost over.  Today is the 32nd day since brooding began in earnest and going on previous years today or tonight should be hatching time.  Although it could be quite hard to tell as the eggs are tucked away behind the side panel of the platform, barely in sight!  Were the eggs in clearer view it might be possible to see some pipping – a tiny hole where the shell is first broken by the chick inside – or perhaps get a clearer indication from the brooding parent that they can hear the chicks in side the egg but so often all we can see is the bird’s back.

Is it my imagination or have the brooding birds been a little more restless the last 48 hours or so?  Moving brooding position more frequently?  Sitting a little more upright, looking more certain?  Any of these, if correct, could be a good sign of something imminent happening.  But it could also be my wishful thinking….

Whatever the case, I take my hat off to the birds as we come to the end of incubation.  What a feat of dedication, commitment and endurance the incubation period is.   They sit there day and night, in hot and cold, through wind and weather resolute, unerring.  The slate grey, white and black head markings of the Peregrine are well suited to a look of grim determination, as they hunker down against the breeze for hours end, day after day.   It’s truly impressive. Perhaps more so considering there’s little feedback from the eggs until perhaps near the end.  It’s a long time to keep the faith.  Let alone without so much as a calendar or a timepiece or any certainty of a successful outcome.  If/when chicks arrive there’ll be plenty to keep the adults busy but at least then there will be feedback, something a little more tangible.  Until then, there’s just waiting.

And they will wait a little longer if necessary.  Whilst we get impatient the birds show no sign of wavering.  The birds has stuck to their task diligently throughout April.  It’s worth noting that Wakefield had their first chick hatch this morning after 35 days, 3 days longer than typical for the site.  So Sheffield Peregrines and their followers may have a few days yet.  Now more than any other time, keep watching!