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.
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.
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….