Wednesday 29 May 2024

Mist netting 2/4/24

On 2nd April, the group were hosts to a visiting group of students from University Centre Reaseheath College, Cheshire. The group has a long-running association with the centre, and has delivered demonstrations for them on multiple occasions. It was therefore a privilege to have them back on site in East Devon.

It was a grey start to the day as the team assembled at Seaton, before collecting kit and heading to base at the cropfield. The usual nets were set across the area, hoping to catch a range of species between them. The site boasts thick hedgerow, scrub, green pasture and thickets, so when nets are spread across the whole area, some variety of catch is near-guaranteed.

The morning got off to a good start with 4 warblers – 3 Cettis, a Chiffchaff and a nice, seasonally fitting, Willow. This proved a good chance for the team to examine the various identifying features of these three related species.

Cettis Warblers – a relatively new resident to Britain, following widespread breeding in 2012 – are unlike most of our other warbler species in the fact that they are largely resident all year. They also have 10 tail feathers, unlike all other passerines, which have 12.

The university group arrived around 9:30am, just as we were processing a net round’s worth of catch. Half of the group stayed to watch this process, while the rest were guided round the site by Mike. Once the birds had been processed, the rest of the team answered questions on catching and measuring techniques, as well as discussing the importance of ringing from a conservational standpoint. Meanwhile, some of the local birds showed nicely around the viewing point, including a handsome male Stonechat.

The university group surveying the site. 
(Robin Pearson)

‘Chiffs’ and Willow Warblers are a familiar duo of similar species that ringers of all guises will be well used to distinguishing in the hand. Nonetheless, it’s always worth 
taking the time at the beginning of the season to re-aquaint ones’-self with the bird’s differences. This bird was first thought to be a Willow based on its overall colour – while not a steadfast diagnostic by itself, most Willows are altogether yellower than Chiffs. A further check of the emargination score (E=5) confirmed that we had caught the former

Willow Warbler (Fiona Coope)

There was, as is so often the case when ringing, a morning lull that lasted for some time – this proved an opportune moment to explain the way in which no two days are the same for ringing, and that, regrettably, sometimes birds don’t read the script! Being ecologically minded students and staff, they were very understanding (a quality which we were very grateful for).
However, after a couple of dud net checks, a single Chiffchaff took pity on us and neatly pocketed itself in the net. This allowed students to view the extraction, as well as the full task of processing, back at base. Finally, the bird was released – perfectly – by a member of the visiting troupe. All just in time for them to head back to their coach. A very good morning

Counting the emarginations of a chiffchaff 
(Robin Pearson) 

Following the visitors’ departure and our dismantling of the nets, we had a final couple of good birds – an (obligatory) Blue Tit, a stonking male House Sparrow (quite seasonal here) and a lovely female Goldfinch – identified by the presence of lighter nasal ‘whiskers’ around its upper mandible. This bird proves the way in which the extent of red on the bird’s head is not always a reliable characteristic to sex this species on – with this individual, the red front does indeed extend just behind this bird’s eye, which, if looked at alone, could be interpreted as an indicator of a male bird. But, the colour of the whiskers suggested otherwise.

Female Goldfinch. (Fiona Coope)

Visiting students & staff (Robin Pearson) 

The ringing team (Fiona Coope) 

Toby Moran Mylett 

Tuesday 21 May 2024

Public session at Borrow Pit

Seaton Marshes and the Borrow Pit are not so popular as the main public area of the Wetlands, but the Axe Estuary Ringing Group are still responsible for monitoring migrant birds at the site. This year, the Group in partnership with East Devon Countryside Team, have arranged for two public demonstrations at the Borrow Pit, one in early May and the second in August. At the May session five members of the public attended and found the ringing activity interesting and encouraged some to show an interest in the Group’s activities. Seventeen birds were ringed of nine species which gave the observers a wide range of birds found at the Borrow Pit.


Mike Tyler 

Friday 22 March 2024

Mist netting 21/3/24

 A small team assembled for a mist netting session around the willows & Stafford Brook. We set up a base in the pond dipping shelter, and finished setting the six nets at about 8am. It was a very quiet morning, despite the perfect ringing weather. We managed to catch 14 birds, 11 new and 3 retraps from previous sessions on site.

Whilst we were processing a pair of Chiffchaffs, a Mallard wandered into the shelter. With the aid of a few crumbs of bread, Neil managed to entice the duck close enough to grab.

Neil with the obviously male Mallard

Neil helping Fran to ring the Mallard

It was aged as an adult due to the size & shape of the black tips of the greater coverts.

Fiona, a Countryside Assistant with the Wild East Devon team joined us for the session, and ringed her 1st birds under Neil's tuition. 

Fiona taking hold of the Great Tit in the ringer's grip. 

Putting the ring on...Great Tits can take one of two sizes of ring depending on the size of the bird's leg

Ageing the bird: this was an adult as the colour of the primary & greater coverts was the same 

Later, two Blue Tits were caught together. The male was a much brighter blue & had a longer wing (65mm) compared to the duller female with a shorter wing (59mm). 

Male Blue Tit (left) and  female Blue Tit (right)

A very pleasant if somewhat quiet morning!


Sunday 25 February 2024

Shelduck Migration Project

At the cannon netting session on 19th February the group took part in a shelduck research project which aims to identify the risks to migrating individuals from collisions with offshore wind farms.  The research is being carried out by Ross Green from the BTO.

Shelduck don't perform the classical spring and autumn migrations between breeding and non-breeding sites like most migrant birds. Instead they migrate in summer – from mid-June to early August – to large estuaries to moult before moving on to wintering sites, which may or may not be near their breeding areas. All the known offshore migration routes pass through areas  that may have offshore wind farms in future. The likelihood of interaction is therefore high, but it is unclear if the interactions will have any effect at the population scale, or an impact on migratory routes in the long term.

GPS data shows that these ducks mostly fly at night, and at heights above sea level that put them at risk of collision with turbine blades. 

Isotopes in the feathers of shelduck may be site specific and so it is hoped that each moult site will have a unique chemical signature. Analysis of feather samples could help to identify the movements of shelduck. 

Our group collected small fragments of secondary feathers at our cannon session and these will help the project by showing where our birds go.

Snipping a section of feather for analysis. 

GPS data has been unable to establish where birds go after they've moulted, so this feather analysis will help to fill that knowledge gap. This method is also considerably cheaper than GPS tracking. 

Robin Pearson

Saturday 10 February 2024

Cannon netting 11/2/24 ....or not!

The catch area at Seaton Marshes had been baited with grain since the last cannon netting session, and decent numbers of ducks and waders, including Shelduck & Black-tailed Godwit, had been seen feeding in the area. The cannon net was set up yesterday, and a team of 12 keen ringers attended for the catch this morning. At one stage there were about 30 Shelduck on the scrape, but they refused to feed on the grain and then flew off. At about 945am the decision was made to give up & disassemble the net. 

The catch area during the week (photo: Adrian Bayley)

The net set & ready (photo: Adrian Bayley)

The disappointed Team 

Wednesday 7 February 2024

Cannon netting 13/01/2024

The group undertook its first cannon netting session of the year at Seaton Marshes. The catch area had been baited for several days. The net was set on the afternoon before the catch day by a few members of the group

Setting the net and the cannon

Weather conditions on catch day were ideal - cold with light winds – as about 15 members of the group waited for the bang of the cannon to send them scurrying down to the net. 27 birds were caught, which was about 2/3 of the birds in the target area. The catch comprised 22 shelduck, 3 teal, one wigeon and one moorhen. 16 of the shelduck were re-traps.

The catch safely bagged and ready for processing

All new shelduck were fitted with a metal BTO ring together with a yellow colour ring with large black lettering which can be read in the field using binoculars or a telescope. 

Fitting a plastic colour ring

Next we determine the sex of the bird and its age. The most obvious difference in the sexes is that males (usually) have a noticeable knob on the bright red bill. The female’s bill is duller.

Female (1st bird shown) and male shelduck for comparison

The principle ageing character is the obvious white tips to the secondaries in immature birds, which give the wing a distinctive white trailing edge in flight. In adults the secondaries are either all black or have only narrow white tips.

Adult birds. Although the 1st bird shown has narrow white tips to the secondaries they are not the broad white tips that would be seen in a 1st winter/spring bird.

Then it’s time to get some biometric measurements: the length of the wing chord (from the bend in the wing to the tip of the longest primary feather); head + bill length; tarsus length (from the notch in the ‘elbow’ to the bend of the foot) and the bird’s weight.

Tarsus measurement is taken from the notch behind the elbow to the bend of the middle toe

Taking measurements and giving them to one of the most important members of the team – the scribe

The team busily at work. 

And away! Birds are released at the water’s edge where they can choose to fly or swim away

Gathering in the net at the end of the session

The three oldest re-trap shelduck were all at least 10 years old and had been re-caught or re-sighted at Seaton Marshes on multiple occasions as detailed in the table below. They were each given the age code 6 at ringing and because age code 6 means ‘hatched before previous calendar year’ they were at least 2 calendar years old when ringed.  

The typical life span of a shelduck is 10 years and the oldest shelduck recorded (maximum age from ringing) was 19 years 7 months (BTO data) so our old birds have not done too badly!

Robin Pearson