Common tern on the menu & watch point feedback

Please note: there will be a Watch Point on Friday 29th May weather permitting!

Given the rain, today's watch point (Weds 27th) has been cancelled.


Joyce Sawford, one of many who visited the top of the tower today, took this photo of a cached common tern in a lead gutter on the West side of the tower.



Common terns have been recorded as prey items before at Derby - as has one specimen of the very closely related arctic tern. This bird was wearing a Swedish ring when it was taken by one of the peregrines - probably in late April/early May 2007.



The bird's remains, including the leg and ring (see photo) were found on the nave roof in August of the same year when Tony and I went up to clean out the gutters. Checking with Swedish ringers, the bird had been ringed as a chick in June 2002 - so it was nearly five years old when it died.


This tern species migrates to the antarctic every winter - one of the longest migrations of any bird on the planet - so this bird (and its ring!) had travelled maybe 100,000 miles during the ten migration flights it had made......a remarkable traveller!





Common terns breed locally in the River Trent valley nearby, nesting on islands and special rafts on reservoirs and gravel pit islands. Arctics, by contrast, are coastal breeders. This bird was probably blown off its usual migration route up the English Channel by strong Easterly winds in late April, forcing it NW to Derbyshire where a flock of 80 was observed at that time at a local reservoir....a fascinating story!

Report on today's Watch point (25th) and tower tours from Andy and Chris:
( Many other activities were also taking place today) Many thanks to Helen and Celia for their help on the watchpoint which became very busy at times.Today started well with ideal weather for watching the birds, warm and slightly overcast followed by a little sun.On arrival the male was sat on the waterspout, the female on the edge of the nest platform and a chick was showing well, pulling some of the down from his body to reveal the feathers now well formed beneath. Some of the down became stuck to the top of mums head for a short time, (Wayne has a picture of this).We had a good turn out of visitors, some regular and some visiting for the first time. It is always great to see everyone and have the opportunity to share views of the birds with them. I hope those who visited for the first time but are regular visitors to the website now have a better idea of where everything is placed.At approx 11am mum flew of and was gone for some time, leaving dad in charge. When the first of the tower tours reached the roof, dad flew displaying nosily but quickly settled after they departed. (There are strict regulations restricting access to the area on the roof nearest the nest to minimise disruption.)Dad flew off leaving the chicks alone for a time. The chicks are now happy to be left and were flapping their wings which were visible from the watchpoint below. Mum returned without any prey and called for the male who she appeared to be able to see but we could not. Two buzzards flew high over the watchpoint at approx 2pm tracked by the male, however they were clearly too far away to be considered a threat. The watchpoint closed at 2.30 when the first few spots of rain started to fall. Wow what timing!!


Nick B (DWT)

More on the arctic tern

Mark Grantham, of the British Trust for Ornithology (BTO), the organisation that runs the UK bird ringing scheme, emailed to say:

"This is only the ninth record of a ringed Arctic Tern from Sweden to the UK, and this is since 1909! There was one sighting in 2001, but before this the last one was in 1992.

Please mention that if anyone does find a ring to report it to http://www.ring.ac/ and they'll then receive details back about 'their' bird.

The BTO's leaflet about ringing can be seen at:
http://www.bto.org/ringing/resources/displays/bird-ringing.pdf

The oldest arctic tern we have is a bird of 29 years and 10 months, though there are Danish and German birds both of 30 years 10 months old and yes, that American bird has reached 34 years of age!"

Nick B

Ps. The map doesn't yet show our Derby bird because we don't know exactly where it was ringed yet......apparently, some dots indicate more than one bird and there are indeed eight records showing!

Some mileage!

Details of the arctic tern have just been received from the Swedish ringing office (see previous post).
It was ringed as a chick on 10th June 2002 on an island off the SW of Sweden (Skane province). So by my calculation, it will have made ten migration trips between Sweden and its Antarctic wintering grounds during the intervening five years, just failing to reach its nesting grounds on its fifth northwards migration of course. That's one heck of a lot of miles! (Arctics have probably the longest migration of any bird travelling right down to the Antarctic Ocean.....anyone like to work out about how many miles that might be?)
Hopefully it had raised enough young of its own during that time such that at least one is surviving and replacing the lost bird, thus keeping the population stable.
Nick B
Ps. Without checking, I seem to recall that the oldest arctic tern aged by its ring was about 30 years old, so that is an even more astonishing mileage. Remarkable birds indeed!
Pps. I should perhaps have pointed out that the red colouration showing on the photo of the tern's leg and foot is not blood. The legs and beak of arctic terns are blood red in colour and this is the remains of that pigmentation.