Friday 23 November 2018

Acro Warblers on Lough Neagh 2018

After our exploratory visits to our new site on the west shore of Lough Neagh in 2017 we were full of anticipation to get back in amongst the reeds this summer.

In 2017 we made two visits to the site producing 197 birds with 30 Reed Warblers, 121 Sedge Warblers, 17 Blackcaps, 10 Willow Warbler, 1 Sparrowhawk 2 Chiffchaff, 1 Wren, 2 Blue Tit and 6 Reed Buntings (which seems rather strange after 2018).

To refresh your minds on last years visits, please follow the links below:

Reed Warbler

The total of 30 Reed Warblers was massive in an Irish and Northern Irish context given that the average catch of the species in NI between 2007-2016 was 3 birds per year and that there hadn't been more than 4 Reed Warblers caught in one year in the initial nine years before 17 in 2016. In the south they have averaged around 25 birds per year for the past 10 years. Certainly for the north, much of the change is down to effort and increased ringing around Lough Neagh once again - in 2015 there was no ringing in the area, one site in 2016, two sites in 2017 and two in 2018. In 2019 we should see this number climb further with certainly three, possibly four sites up and running, including two Constant Effort Sites with Portmore Lough being brought back into action after decades of no ringing - this site has produced over 1000 Sedge Warblers in certain years in the past and 1/2 Reed Warblers when they were much rarer back in the 1970's/1980's.

In 2018 we made three visits to the site on the 22nd of July, 11th of August and the final visit on the 25th of August producing 126 new birds (+2 controls), 182 new birds and 165 new birds respectively. Sedge Warbler numbers were pretty consistent across the three visits with 98, 97 & 84 respectively with Reed Warblers increasing across each with 10, 12 and 19. 

On the third visit there were noticeable gatherings of hirudines (and Swifts) feeding over the reedbeds and wet woodland so once the deluge of Acrocephalus (acros) warblers had subsided we had a go at tape luring some, successfully catching 15 Swallows and 3 Sand Martins with many more landing on top of the nets and poles and avoiding capture in the bright sunshine. I've never visited the Lough in the evening or at night but undoubtedly there must be some massive hirudine roosts forming all around the lough in autumn and our site seems better than most for potential habitat.
Through lack of extra hands we still haven't fully explored the potential of the backing wet woodlands but we did catch 26 Blackcap, 19 Willow Warbler and 4 Chiffchaff in short spells but a concerted effort would produce much more and perhaps a secret pair of Garden Warbler - the habitat is perfect (we may have as few as 50 breeding pairs in Ireland, generally around the Lakelands of Fermanagh, Leitrim, Roscommon and Cavan).

The combined totals of the three visits were:
Blackcap                      26
Chiffchaff                      4
Reed Bunting              83 (2)
Reed Warbler              41 [1 NW England control]
Robin                            2
Sand Martin                  3
Sedge Warbler            279 (1) [1 French control]
Swallow                        15
Willow Warbler            19
Wren                             1

Total                            473 (3) [2]

Reed Bunting

The biggest surprise of the year was the numbers of Reed Bunting around and the number caught. On the second visit an incredible 53 were caught (for not being a roost catch this is spectacular), an impressive 21 on visit three and a very decent 9 on visit one. Given that we only caught 6 in both visits combined in 2017 this is a massive change and 2019 might let us know what is normal! 

Having gone through the first autumn migration without a recovery from the 180 ringed warblers we were really quite surprised, particularly for Sedge Warblers which are readily controlled in the habitats they stopover in on migration. We were then even more surprised that we avoided any recoveries on the return journey north. 
The first visit of the season produced the goods with two controls, a very nice French ringed Sedge Warbler and a BTO ringed Reed Warbler which was even better in our minds! The Reed Warbler had been ringed at Middleton nature Reserve at Heysham Bird Observatory in Lancashire. Interestingly one of the ringers there, Pete Marsh, used to ring on our stomping grounds in the Bann Estuary back in the early 1970's and he reported that the Reed Warbler had arrived in a fall, including birds ringed elsewhere with 2 Sedge Warblers ringed in France and another in Belgium - did they all head to Ireland also?
A week after we received the details of our French control Sedge Warbler, we received news that one of our Sedge Warblers from this year had been recovered on the way south in France.

Sedge Warbler Movements (green) and Reed Warbler (light blue)

The Reed Warbler was originally ringed at Middleton Nature Reserve, Heysham on the 04th of May 2018 and controlled by us 79 days later at a distance of c151 miles.

The Sedge Warbler was originally ringed near La Rochelle on the west coast of France on its way south on the 11th of August 2017. It then spent the winter in sub-Saharan Africa before returning to Northern Ireland to breed for the first time, 345 days later, at a minimum distance of 1087 km but in reality this will be much more.

Our recovered Sedge Warbler was a juvenile ringed on the 11th of August this year and was recovered in Dourges in NE France 17 days later at a minimum distance of 790km. Normally we would expect these birds to stick to the west of France on their way to Africa but that's part of the beauty of the study of migratory birds.

Sedge Warbler

Limitations and Restrictions
As a ringing group, all of us are located 70-90 minutes away from the site, so regular visits and very early starts are difficult to enable the full monitoring the site deserves. The walk into the site is also over a mile long striding through reeds and wet grassland and not the easiest with all the equipment but the shear volume and quality of birds makes it very worth while. Getting sufficient pairs of hands in 2018 was our biggest restricting factor in regards to the number of nets we can use and also keeping the limited number open - at times the birds enter the nets faster than they can be extracted, let alone processed so the nets are closed until all birds have safely processed and released before reopening. Early morning seems to be the key time for the movement of birds with birds pouring through before tailing off before 9am, with basically no birds being caught around 10am. Normally on arrival the birds are in full flow and we've caught up to 17 birds in two joined nets in the process of erection which only takes a couple of minutes.
Cost is also a consideration when ringing such volumes of birds, the current price per bird for an A ring is 25.2p, so for the 449 ringed in 2018 equates to £113.50 + a further £5.07 in AA rings. Thankfully I have been able to source some funding sources over the past 4/5 years to pay for some of the rings, most notably to the Centre for Environmental Data & Recording (CEDaR) who covered the cost of 1000 A rings for 2018, but having never charged our T's & C's (and no plans to do so) there is still a financial burden into the £100's each year for myself and John. A CES would help us get a real understanding for the local breeding population of the site and take away the financial burden but unfortunately we couldn't commit to the effort at the moment!

..... but after all that, we do hope to increase our studies at the site next year to increase our understanding of the breeding birds on site, the turn over of birds in 24 hours and potentially investigate the sites potential in the evening (= overnight camping!).
If I get some time over the winter (on top of everything else I take on and pile up) I may take a look at the patterns from previous recoveries of the migration routes taken by be Sedge Warblers with the UK and Ireland to and from Lough Neagh of which I think there are three main routes - via NW England (possibly more so spring?), direct line through Wales out of SE Northern Ireland and NE Ireland and some to SE Ireland before making the leap to SW Wales and SW England.

The fresh wing (lower) of a juvenile Sedge Warbler and worn wing of an adult (upper)

A big thank you to John Clarke, Steve Fyffe, David Stirling, David Galbraith, Ken Perry, James O'Neill and James McDowell who were present at one+ of the visits and to Godfrey who gives us access to the site and is always on hand to assist. 

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