Donegal Sandwich Terns June 2019

Continuing our long term monitoring of breeding Sandwich Terns in Donegal, which began back in 1986 (before I was born), we returned to Inch Island Wildfowl Reserve in Donegal for two visits this summer.

The first visit took place on the 4th of June with a team of Ken Perry, James McDowell, Gary Platt and myself with Lee and Martin from the National Parks and Wildlife Service (NPWS). 

Keep your eyes peeled for these Blue darvic rings with 3 numbers in white

Our plan was to finally kick off our Sandwich Tern colour ringing programme after last years delay but being so early in the season we weren't too optimistic. We managed to metal ring 193 Sandwich Terns and also added colour rings to the eight largest chicks we could find. We limit ourselves to a maximum of one hour on the breeding islet to minimise disturbance so time is a very limiting factor. There were still plenty of very small chicks that we did not ring and also lots of eggs.

Gary Platt accompanied us on the trip and his main focus was on the breeding Black-headed Gulls. Gary runs colour ringing schemes on both Black-headed Gulls and Common Gulls in the north of Ireland and is one the most dedicated ring readers in Ireland. Gary managed to colour ring 28 new Black-headed Gull chicks. He also sighted two colour ringed Black-headed Gulls from 2017 but without his gear he was unable to read the rings - great to see them back though. 

Gary is also using blue darvic rings with white ringing on this current cohort but a four digit code starting with the number 2 with three letters after.

Katherine and I colour ringing a Sandwich Tern

The second visit took place on the 19th if June, this time Ken, Gary and I were joined by John Clarke, Katherine Booth Jones and Abbie Maiden as well as Lee, Martin & Ger from the NPWS. 

The heavens opened up on our way out across the lagoon in the small boat but thankfully it just stopped as we arrived on the islet. The rain started again just as we were leaving, so we got very lucky indeed.

Ken, John and the ladies focused on metal ringing Sandwich Terns and added another 68, taking us to a year total of 257 for the year.

This is a decent total compared to visits in the past 10 years

2018 -100

2017 -  139

2016 - 357

2015 - 189

2014 - 270

2013 - 251

2012 - 410

2011 - 94

2010 - 387

My focus was on colour ringing the largest Sandwich Tern chicks from the previous visit and I was able to add a further 22 chicks, giving us a total of 30 colour ringed Sandwich Terns - roll on the recoveries. We are particularly keen for recoveries in Ireland, as, if you check out the Tern & Gull tab above, we have more from 5/6 countries in Arica than we do in Ireland. 

The Common Terns breed in much smaller numbers and are always a few weeks later so just 14 were ringed. A further 4 large Black-headed Gull chicks were metal ringed for training.

Gary was again focused on colour ringing Black-headed Gulls and discovered two of the marked birds from the 4th had perished so the colour rings were reused. 26 more chicks were colour ringed giving a total of 52. You can check out Gary's blog on the link below

http://birdingatantrimmarina.blogspot.com/

One of the returning birds from 2017 (Gary Platt)

We have identified some habitat works to be carried out on the islet post breeding season to boost the breeding population. Originally the islet was open shingle and sand but overtime the vegetation has increased. The Terns prefer to nest on the bare ground and are being forced off the high of the island towards the lower edges and a number of nests have been lost in the last few years to higher waters. This is often the reason the Common Terns do not do too well here.

A big thank you as always to the NPWS for making supplying the boat, rings and maintaining the breeding islet. 

June 2016

I've arrived back in Northern Ireland to pretty cold, wet and breezy conditions, so I haven't been able to jump straight back into any ringing but the others have been doing bits and pieces over the last three weeks.  We also received news of our best Blackbird control yet plus some new funding!


On the 22nd of June, the team assembled at Inch Wild Fowl Reserve, Donegal for the final visit of the season to the Gull/Tern colony, hoping to ring the remaining chicks.  Ken, John and the National Parks and Wildlife Service Team were again joined by Adam and Gary from the Northern Ireland Black-headed Gull Study.
The weather had taken a bit of turn over the preceding weeks with more wet/cold weather and some thundery showers, resulting in higher water levels (closer to the norm), making access to the Islet much easier than the previous visit. 
The results were a little disappointing considering the potential of it shaping it up to be one of the best years at the colony.  The Sandwich Tern result was decent with 22 more birds ringed from the c30 eggs counted on the previous visit.  These 22 birds take the total up to 357 birds for the year, which compares well with previous years.  2016 represents the sixth most successful breeding year for Sandwich Terns in the 31 years of the study, the most productive year was 453 birds ringed in 2004.  For more information, check out the Terns/Gulls tab above.

Common Tern

Common Terns on the other hand were the big disappointment with only 22 birds ringed from what could have been over 150.  The Common Terns nest at the edge of the colony so are a little more susceptible to predation, changes in water levels and probably the weather.
It would appear that predation, potentially from large gulls, is the issue.  Twenty odd larger Black-headed gull chicks were found dead at the edge of the tern nesting area and looked to have been killed.  We reckon that it is more the case of missing eggs, rather than chicks.  A total of 32 Common Terns were ringed this year, which is just one more than the previous year and much better than the years of complete breeding failure. 



Adam and Gary were again busy colour-ringing Black-headed Gull pulli and added a further 52 new birds to the study, making it a grand total of 122 colour-ringed BHG's at Inch, plus a further 39 metal ringed.  The numbers ringed looks very favourable against numbers from the last 31 years but BHG's have never been a focus of study in the past and the total this year represents only a fraction of the population of the islet.  It will be really interesting to see where these guys start to crop up in future years and whether many will return to breed on the Islet. 
You can stay up to date with any findings on the Northern Ireland Black-headed Gull Study Blog or their Facebook Page - the blog can be found on the following link -   http://bhgullsni.blogspot.co.uk/

Colour-ringed Black-headed Gull

It has been a while since we got a long-distance control, so we were very pleased to receive news of a Blackbird that I had ringed in my garden, had been recovered in Norway!  The bird was found in unfortunate circumstances with just its leg and the ring recovered all the way up in Hundorp, Opland.  The female, born in 2013, was originally ringed on the 2nd of January 2014 and recovered 881 days later on the 1st of June this year, presumably on its breeding grounds.  The straight line distance between the two locations is 1202km.  This is our first control to Norway but hopefully not the last. 

Blackbird control to Hundorp, Norway

John and Steve visited the new Sand Martin colony at Grangemore a few weeks back for the first time to test out its potential.  The late morning visit was a little breezy and made the nets a bit obvious.  The colony is on the outer bank of a meander on a small tidal river, which makes setting a net quite difficult.  They opted for an 18m, 3 shelf net but a few shorter nets may be more suitable in future visits.  The catch was decent enough considering the conditions with 16 new birds caught.  14 of these birds were juveniles plus two adult females.  The following two visits will hopefully pick up more of the adult birds plus more of the juveniles.      

Sand Martin

The final bit of good news is that we were successful in gaining a little bit of funding from the Centre for Environmental Data and Recording at the National Museums Northern Ireland.  An application had been put forward for the Environmental Recorders Group Fund to cover the cost of rings and we received partial funding.  The £137 granted is around a quarter of the amount requested but it will still go a long way in enabling our scientific research and we are very grateful to CEDaR. 

Inch Island - Terns and Gull

On Wednesday morning, Ken, Steve and I headed up to Inch Wild Fowl Reserve in Donegal to study the breeding Sandwich Terns for the 31st continuous year.  We met up with a team of four from the Irish National Parks and Wildlife Service and were also enjoyed by Adam and Gary from the Northern Ireland Black-headed Gull Study.  The weather has been brilliant with temperatures hitting 30°C in recent days but torrential rain on Tuesday afternoon had us a little worried, as, this is often a major killer of chicks during prolonged periods.  It turns out that it hadn't been too bad around Inch and the day itself was dull, calm and warm - perfect conditions!

The really dry weather presented us with a new problem and that was really low water levels, in what is already a relatively shallow lagoon.  The Islet itself was now probably 150% larger, although much of that was thick, sticky mud/clay.  We had to do quite a bit of manoeuvring to get the boat in position to ferry people across the short crossing which was now only roughly 75 metres.  Andrew did a great job getting us across safely and would probably be quite nifty on the Gondolas in Venice! 

Sandwich Tern

I had mentioned the success of the previous visit in a recent post and the great year continues.  The small islet was covered in chicks and nests with Sandwich Terns, Common Terns, Black-headed Gulls, Tufted Ducks, Mute Swans and Mallard.  The majority of the 200+ Sandwich Tern eggs on the last visit have now hatched with around 30 left to go.  The Common Tern colony has increased further with many new nests, again mostly with three eggs.  Only a handful of the eggs have hatched but should be out for the final visit in a couple of weeks.  The Black-headed Gulls are the most numerous bird on the island and I would hazard a guess at a of 500 pairs, probably many more.  They are at many different stages with birds already fledged, to eggs yet to hatch and everything in between. 

The greeny/brown areas the newly exposed parts of the Islet because of the low water levels

The trip was a great success with another 154 Sandwich Terns ringed, taking the total up to 334 and the first 10 Common Terns.  Adam and Gary have a colour ringing project for Black-headed Gulls in the North and have picked up metal ringed birds from Inch as part of their study.  They came armed with colour rings and added 70 new birds to the study with 66 of those being new birds and 4 from the last visit when 43 were ringed.  The majority of the birds colour ringed were well developed chicks, close to fledging.  The colour rings are orange with a four digit alpha-numeric black inscription.  The first digit is always the number 2 then three letters after e.g. 2ABC.  Please keep an eye out for these birds and for more information check out: http://bhgullsni.blogspot.co.uk/ .


You can follow updates from Inch Wildfowl Reserve on Facebook - https://www.facebook.com/inchandfoyle/?fref=ts

We plan to do the first visit to the Sand Martin colonies on Saturday before I head to Croatia for three weeks.  I'll try and post an update on that before I head off on Sunday.  Looking at other first visits around the UK it looks like the Sand Martins have bred early with come catches of up to 30% juveniles already! 

Gulls and Terns since 1984

Over the past few weeks I have been playing about with Kens Gull and Tern data, that he has collected over the past 32 years.  Over this period he has ringed over 10,000 birds, with a focus on Sandwich Terns, with 8377 ringed since 1986.  Other important species were Black-headed Gull, Common Gull and Common Tern. 
Much of the early study work was carried out on the islands of Mulroy Bay, Donegal but the invasive American Mink became a huge problem and devastated the colonies.  The Mink not only ate as they went, but also killed every sitting bird they found (left uneaten) and cashed hundreds of eggs in burrows.  The Mink are still prevalent in the area and it is no longer studied.  Since then Inch Islet, at Inch Island Wild Fowl Reserve, has become the sole focus for study.  The islet has breeding populations of Common & Sandwich Terns and also Black-headed Gulls - Common Gulls are thus no longer ringed.   
As you can see from the totals below the Sandwich Terns have remained fairly constant, with the one blip in 2011, when high water flooded the whole islet.  This year was also quite poor, with the bad weather in early summer, killing many chicks and lots of eggs were abandoned.  The Common Terns are much more susceptible to changes in water levels, because they nest just above the water mark.  Black-headed Gulls breed in big numbers on the island but there is little focus on this species.   
  

	Tern Species - Chicks Ringed				Gull Species - Chicks Ringed
	Arctic	Common	Sandwich		Black-headed	Common	Great Black-backed	Herring
1984		100			98	160
1985		31			50	145
1986			203		5	71
1987	10	14	133		16	136		3
1988		26	415			138
1989			342			131
1990			267			22
1991			144
1992			238
1993			294
1994			320
1995			197
1996			329
1997			131
1998		45	155		15
1999		86	324		95	3
2000		19	365			3
2001		24	335		49
2002		26	267			5
2003		23	272		5
2004			453			2	3
2005			317
2006			322
2007			343
2008			319
2009		11	291		10
2010		12	387		9
2011			94
2012		6	410		7		2
2013			251		26
2014		22	270		5
2015		31	189		22
Total	10	476	8377		412	816	5	3

Since the start of the project there have been 113 recoveries (more than 5km away) of the birds ringed.  The Sandwich Terns, as expected, have weighed in with the majority, with 94 recoveries.  The birds that are recovered experience a wide range of fates.  For those lucky they have had their rings read in the field, have been re-caught by ringers or caught unintentionally and released.  Some are not so lucky with many being trapped and eaten, kept in cages, kept by children as pets, trapped for their rings to make jewellery, caught by dogs or simply found sick/dead. 

The Sandwich Terns have been recovered in an impressive 23 countries (24 if we grant the Basque independence) although surprisingly none yet in Northern Ireland.  I suspect some of the ringed birds I see in the Bann Estuary originate from Inch.  Generally the main concentrations in West Africa are found near the main cities e.g. Dakar and this is down to the population size, increasing the chances of the birds being found/caught.  Thumbs up to the people who found the birds in the Namib desert! 
The biggest distance travelled was for a Sandwich Tern that reached Sardinia Bay, Port Elizabeth, Cape Province, South Africa at a straight line distance of 10,399 km.  The bird was approaching 5 years old when it died, so it may have flown to South Africa and back to Ireland three/four times.   
 In terms of longevity there have been a few birds that have passed the 15 years old mark but the oldest two birds were both recovered in Spain at the ages of 20 years, 10 months and 5 days and 20 years, 4 months and 13 days.  The majority of the birds recovered in the Europe are generally at least 3 years old, whereas many of the birds in West Africa are recovered in their first winter or second year.

Sandwich Tern Recoveries
Ireland	8	Guinea Bissau	2
Scotland	3	Guinea	1
Wales	1	Sierra Leone	7
England	5	Liberia	2
France	2	Ivory Coast	3
Belgium	1	Ghana	8
Netherlands	1	Gabon	1
Germany	1	Congo	6
Denmark	2	Angola	2
Spain	3	Namibia	2
Morocco	1	South Africa	8
Senegal	24
		Total	94

 

 

Sandwich Tern Recoveries - Europe & North Africa

 

Sandwich Tern Recoveries - West Africa

 

Sandwich Tern Recoveries - Southern Africa

 

 

 

With much fewer birds ringed, there are less recoveries for the other species.  The Common Terns have managed a couple of recoveries in Ghana.  In terms of longevity, the oldest Common Tern to date stands at 11 years, 3 months and 1 day.  The oldest Black-headed Gull recorded = 12 years, 8 months and 6 days  and Common Gull = 21 years, 6 months and 3 days. 

Commn Tern Recoveries			B-headed Gull Recoveries			Common Gull Recoveries
Ireland	3		N Ireland	3		N Ireland	1
England	1		Ireland	7		Ireland	9
Ghana	2		Scotland	1		Scotland	1
			England	1
Total	6					Total	11
			Total	12

 

Recoveries of Black-headed & Common Gull and Common Tern - North of Ireland

Recoveries of Black-headed & Common Gull and Common Tern - UK & Ireland

Common Tern Recoveries - Ghana

 

 



All this information will be available in the Projects tab once I get around to updating it!