Guernsey Gulls

Annual Report for 2010

Paul K Veron & Helen Wain

INTRODUCTION

2010 proved to be the most successful year so far for the gull research projects based in the Bailiwick of Guernsey. Not only were very good numbers of adult and nestling gulls ringed, but high levels of colour ring readings were recorded both within the Bailiwick, and outside the islands. Work on the gull studies fell into eight principal areas as follows:-

Colour-ringing adult/full-grown gulls in a cannon netting operation run from 26-29 May at Chouet Landfill with Paul Roper and members of the North Thames Gull Group;

Colour-ringing adult/full-grown gulls caught in our garden at Ty Coed, Vale Marais Guernsey during the period 04 April – 05 June;

Colour-ringing breeding adults trapped on the nest (on Burhou, Alderney, and two of the Sark colonies);

Colour-ringing nestlings on all the main islands of the Bailiwick;

Sightings of “Guernsey” colour-ringed birds in the Bailiwick of Guernsey;

Sightings of “Guernsey” Colour ringed gulls outside the Channel Islands;

Sightings of “Foreign” colour-ringed gulls in the Bailiwick of Guernsey; and

Foreign Gull Colour ring reading trips.

 In such a successful year it is particularly difficult to pick out only a couple of highlights. However, it was hugely exciting in the spring to be able to record the arrival dates of 125 adult Lesser Black-backed Gulls colour-ringed in Guernsey in 2008 or 2009. All of these gulls had wintered outside the Channel Islands, with many having been sighted the previous autumn/winter in Iberia, France or England before returning to their breeding areas in the Bailiwick. The results of this research have been documented and submitted for publication in the international journal Seabirds.

 After the successes of ringing adults and chicks in 2010 it was also very rewarding for Catherine and me to follow our Lesser Black-backed Gulls south and look for them once again in November in the Algarve, Portugal and then a month later in Agadir, Morocco. In this way we located a dozen of our own “Guernsey” Lesser Black-backed Gulls in Portugal, and seven in Morocco. It was an awe-inspiring experience to see our own gulls in Africa!

 CANNON NETTING AT CHOUET LANDFILL, GUERNSEY

Paul Roper and six members of the North Thames Gull Group very kindly came over to Guernsey from 26-29 May inclusive to use a cannon net to catch gulls at Chouet Landfill. Despite losing half of the available time to poor weather the Team, together with seven to nine Guernsey personnel, was able to make seven cannon net catches over two days (27 and 28 May). As a result a total of just over a thousand gulls was caught (184 Lesser Black-backed Gulls and 824 Herring Gulls).

North Thames Gull Team at Chouet Landfill 28 May 2010

GULLS CAUGHT AT TY COED, VALE MARAIS, GUERNSEY

With Lesser Black-backed Gulls being the principal target species for the gull studies, I took the decision this year to try to only take catches in the garden which included this species. On several occasions there were too many Herring Gulls in the catching area and as a result the majority of gulls were able to lift the net and escape before being caught and ringed. The 2010 gull catching season in the garden was therefore somewhat frustrating. Despite all the problems catches were taken on eleven days - April (four), May (six) and June (one). A total of 190 gulls was achieved (32 Lesser Black-backed Gulls and 158 Herring Gulls).

 Paul Veron with Larus fuscus Black 1.S2 Ty Coed 16 May 2010

BREEDING ADULTS TRAPPED AT NEST COLONIES

Colour ringing adults at their nesting colonies is especially valuable, as the nesting areas of the birds are known with certainty. Valuable data can then be accumulated on adult migration strategies and survival rates, and over time these can be compared with those of birds ringed as chicks. At present only Lesser Black-backed Gulls are being caught at their colonies. Most work takes place over just two days in mid-June on Burhou, Alderney, but smaller numbers of adults are also ringed on one or two of the smaller Sark colonies. In 2010 a total of 93 adult Lesser Black-backed Gulls was caught at their colonies - Alderney (75) and Sark (18).

Catherine Veron with Larus fuscus Black 3.X5 Burhou 13 June 2010

Paul Veron with Larus fuscus Black 4.C4 Burhou 13 June 2010

 NESTLINGS

Following on from the largely successful breeding season for gulls in the Bailiwick in 2009, 2010 proved to be (if anything) even more productive. All three nesting species appeared to enjoy good productivity at most of their colonies – the notable exception being on Lihou, Guernsey where the small colony of Lesser Black-backed Gulls appeared to fail completely, while Great Black-backed Gull chicks were less numerous on that island than in some years. The Lesser Black-backed Gulls on Burhou (their most important colony in the Channel Islands) once again fared well, and there were noticeably more Herring Gull chicks there in 2010 than in the previous two years. 

Priority in Sark was given to ringing Lesser Black-backed Gull chicks, and as a result the majority of Herring Gull chicks were too large to catch and ring on the Sark visits. This explains the low number of Herring Gull chicks ringed on that island, where productivity was encouragingly high.

 Totals numbers of chicks ringed by island were:-

 Lesser Black-backed Gull – Alderney (335 including 259 colour rings), Sark (88 including 70 colour rings) and Guernsey (one) – Totals (424 including 330 colour rings);

 Larus fuscus chick Black 6.V9 Burhou 10 July 2010

Herring Gull  - Guernsey (195 including 82 colour rings), Sark (18 including 17 colour rings) and Alderney (17 including 15 colour rings) – Totals (230 including 114 colour rings).

Larus argentatus chicks 6.AH8 & 6.AH9 Jethou 22 June 2010

Sophie Veron with Larus argentatus chick 6.AH2 Jethou 22 June 2010

 Great Black-backed Gull – Guernsey 66 (including 52 colour ringed) and Sark (four including three colour ringed) – Totals (70 including 55 colour ringed).

 Larus marinus chick 0.FF2 Lihou Island 11 June 2010

SIGHTINGS OF “GUERNSEY” COLOUR RINGED GULLS IN THE BAILIWICK

The purpose of colour ringing gulls is to be able to identify individual gulls in the field without the need to recapture them. A critical part of any colour ringing project is therefore the time spent in the field observing and recording colour ringed birds. 2010 has been an exceptionally good year for this aspect of the studies with around 12,500 individual records of “Guernsey” colour ringed gulls being taken within the Channel Islands – principally on Guernsey. The majority of these records refer to Herring Gulls (c. 9,200), but there were also very good numbers of Lesser Black-backed Gulls (c. 2,700) and Great Black-backed Gull (c. 675). Given the numbers of records involved it is now necessary to store the data in databases which are easy to interrogate and analyse.

 One of the highlights of 2010 has been recording the spring arrival dates in Guernsey of 125 adult Lesser Black-backed Gulls which were colour ringed in Guernsey during the summers of 2008 or 2009. These birds are believed to belong to the islands’ breeding population, which remains fully migratory with no breeding birds remaining in the Channel Islands in winter. Many of the birds observed in the spring 2010 had been recorded the previous autumn/winter in Iberia or France. This is the first time the spring arrival of Lesser Black-backed Gulls has been recorded in the Channel Islands and a paper documenting the results has been accepted for publication in the international journal Seabirds.

Larus fuscus White 7.T5 Chouet Landfill 17 April 2010

 A simple analysis of the local sightings of Bailiwick of Guernsey-ringed Lesser Black-backed Gulls in 2010 has also provided further evidence that the gulls nesting on Guernsey, Herm and Sark make widespread use of the food source available at Chouet landfill, while those nesting on Burhou, Alderney do not (as a general rule). The lack of any observations of colour ringed Lesser Black-backed Gulls in November and December 2010 adds further credence to view that the whole of the Bailiwick’s breeding population of Lesser Black-backed Gulls migrates away from the islands in winter.

 Larus fuscus White 1.T9 Chouet Landfill 16 April 2010

Larus fuscus Black 0.R0 Chouet Landfill 30 April 2010

 Given the size of the Herring Gull databases it is very difficult to analyse the data without further computerisation (which is now taking place thanks to Rich and Margaret Austin, Charles David and Helen Wain). Nonetheless observations of colour ringed Herring Gulls this year (mostly at Chouet) is revealing the variations in how extensively Herring Gulls use the food source at Chouet Landfill, and the proportion of the adult population which migrates out of the island each late summer/early autumn - only to return again before the end of the year, in advance of the next breeding season.

With the smaller number of Great Black-backed Gulls being colour ringed in the Bailiwick, it is taking longer to build up sufficient data to be able to analyse and interpret the movements and migrations of our locally born birds. However, further progress was made in this area this year.

SIGHTINGS OF “GUERNSEY” COLOUR RINGED GULLS OUTSIDE THE CHANNEL ISLANDS

The value of colour ringing (as opposed to simply metal ringing) gulls is revealed by the simple statistic that in 2010 there were 721 reports of Bailiwick ringed gulls observed outside the Channel Islands, involving no fewer than 425 different birds!

 Lesser Black-backed Gulls were sighted in Spain (278 involving 140 birds), Portugal (219 involving 138 birds), France (60 – 38 birds), England (27 – 15 birds), Morocco (14 – eight birds) and The Netherlands (one). Total = 599 sightings of 340 birds.

Larus fuscus White 3.U5 Quarteira, Portugal 28 September 2010 – Michael Davis

Larus fuscus Black 6.P4 Colmenar Viejo Landfill, Madrid, Spain 11 October 2010 – Delfín González

Larus fuscus Black 4.T8 Praia de Beluso, Bueu, Pontevedra, Spain - 29 October 2010 Alberto Pastoriza Barreiro

Herring Gulls were sighted in France (88 involving 65 birds), England (16 – nine birds) and Spain (five – two birds). Totals = 109 sightings of 76 birds.

Larus argentatus White 3.JJ5, Charente-Maritime, France – 10 September 2010 Julien Gernigon

Great Black-backed Gulls were sighted in France (eight involving four birds), and England (five different birds). Totals = 13 sightings of nine birds.

Larus marinus Yellow 0T1 St-Vaast-la-Hougue, Manche, France –  14 December 2010 – Samuel Crestey

 Such statistics hide much of the value of these reports. Given the volume of such data it will, in the years ahead, be possible to compare migration strategies and survival rates for gulls breeding in some of the various colonies in the Bailiwick. The differences in strategies between ages and sexes may also be revealed, as will any temporal changes caused by variations in weather or local circumstances (such as the operation of Chouet Landfill in Guernsey).

 Many of the individual gulls are now building interesting life histories which reveal not only site fidelity to their breeding colonies, but also to their wintering areas.

 The data is not yet in a form where it can be easily mapped, but it is hoped that within the next year such analysis will be readily available, so that some examples can be incorporated into future annual reports.

 Of all the above reports, none have been more satisfying than the 12 Bailiwick-ringed Lesser Black-backed Gulls seen by Catherine and me in the Algarve, Portugal in November, and the seven seen at Anza just north of Agadir, Morocco in December. It is proving to be very worthwhile following our Lesser Black-backed Gulls south each winter. In particular, the sight of our own gulls so far from home in Africa is one of the most awe-inspiring experiences of my 40 years bird watching!

 SIGHTINGS OF “FOREIGN” COLOUR RINGED GULLS IN THE BAILIWICK

Although not central to my own gull colour ring studies, an inevitable bonus of all the time spent searching for my colour ringed birds is the sighting of gulls which have been colour ringed outside the Channel Islands. In this regard 2010 has been the most successful year to date with 423 observations of 140 different gulls. Colour ringed Great Black-backed Gulls are the most frequently observed (313 sightings of 82 birds). The majority of these records refer to gulls from two French projects – one based on the Chausey Islands, Manche run by Sebastien Provost (134 observations of 35 different Great Black-backed Gulls) and the other based at Le Havre, Seine-Maritime run by Gilles Le Guillou (155 observations of 35 gulls). In addition there 11 sightings of four English-ringed gulls (Cornwall – seven sightings of three gulls, and Essex four sightings of one bird), and 13 sightings of  eight Norwegian-ringed Great Black-backed Gulls (Vest-Agder nine observations of six gulls and Finnmark four observations of two birds).

Larus marinus Black J1063 Chouet Landfill Beach 07 August 2010

 Of the 17 sightings involving ten Herring Gulls, 14 were from England (Bristol one, Gloucester six, Essex six and Sussex one), while the other three (involving three birds) were from France (Le Havre, Seine-Maritime two and Cotes d’Armor one).

 As expected sightings of colour ringed Lesser Black-backed Gulls reveal the most widespread geographical origins. In 2010 there were 93 sightings involving 48 Lesser Black-backed Gulls ringed in eight countries. The most frequently seen (63 sightings of 30 birds) were from England (Bristol 11 sightings involving nine birds, Gloucester 48 (17 gulls), Lancashire/Cumbria (three (three gulls) and Essex (one sighting). A further six sightings (five birds) referred to four gulls ringed on Flat Holm and one at Newport, Wales.

Larus fuscus Lime 4WF (from Flat Holm, Wales) Chouet Landfill Beach 09 April 2010

 Beyond this Lesser Black-backed Gulls were also observed from Iceland (four records of two birds), Norway (Vest-Agder – two records of two birds), Germany (three records of two birds), The Netherlands (eight records of five birds), Belgium (one bird) and Spain (six records of one bird).

Larus fuscus Green X:05 (from Malaga, Spain) Chouet landfill 10 April 2010

 Only one colour ringed Mediterranean Gull was seen in Guernsey in 2010. This was the well-known bird White 3E90, which was ringed at Zandvlietsluis, Antwerp, Belgium in June 2002, and which has been seen in each of the past five autumns at Bellegreve Bay, Guernsey. In 2010 the bird was recorded between 21 July and 12 September.

 Two colour-ringed Black-headed Gulls were observed. White TARM, ringed as an adult on 05 June 2010 at Przykona Reservoir, Radyczyny, Turek, Poland, was seen at Bellegreve Bay and Chouet, Guernsey between 14 August and 01 September, while Black P547, ringed as an adult male on 01 April 2010 at Klaipda Landfill, Lietuva, Lithuania, was seen on 30 August and 15 October at Crabby Bay, Alderney. In addition one metal ring was read. This was a bird ringed as a chick in May 2008 at Januszkowice, Zdzieszowice, Opolskie, Poland, and observed on both Guernsey’s east and west coasts from 31 August to 02 September.

FOREIGN GULL COLOUR RING READING TRIPS

Two foreign trips were made in 2010 to record colour ringed gulls. A first attempt to travel to the Algarve, Portugal in January was thwarted by heavy snow at London Gatwick Airport. This rescheduled trip finally took place in mid-November. As reported above the highlight of this trip was the sighting of a dozen different “Guernsey” Lesser Black-backed Gulls, amongst the 96 such colour ringed birds seen. The Guernsey birds included three ringed as chicks and one as an adult in 2009, and three adults, four chicks and a 2nd calendar year from 2010. Some of these gulls already have other sightings in Spain and Portugal, and one of the 2009 chicks had been seen in September 2010 in The Netherlands.

The other colour ringed Lesser Black-backed Gulls originated from:-

Norway (6), Denmark (5), Germany (3), Iceland (4), The Netherlands (25), Belgium (14), England (20), Wales (4), France (2) and Portugal (1).

 The principal sites visited were Quarteira/Vilamoura Beaches, Portimao Fish Port, Porto de Lagos Landfill and Tavira saltpans.

Paul Veron watching gulls on Vilamoura Beach, Algarve, Portugal 18 November 2010

Other colour rings were read on White Storks (Portugal (2) and Germany (1)), Mediterranean Gulls (Belgium (2), France (5), Italy (1) and Hungary (1)), Yellow-legged Gull (Portugal )1)) and Audouin’s Gulls (Spain (2)).

Ciconia ciconia at Porto de Lagos Landfill, Portimao, Portugal November 2010

 The second foreign trip was made to Agadir, Morocco in mid-December. Just to the north of Agadir Port a sardine processing factory discharges fish waste onto the beach. As a result this small beach (one km long) has become a magnet for gulls, especially wintering Lesser Black-backed Gulls. At times there were c. 20,000 gulls on the beach.

Gulls at Fish Waste Discharge, Anza, Morocco – 17 December 2010

 Larus fuscus Black 5.T6 (from Burhou, Alderney) at Anza 17 December 2010

 187 colour ring readings were taken on 128 Lesser Black-backed Gulls – including seven Bailiwick of Guernsey ringed birds (five chicks ringed on Burhou (four in July 2010 and one in July 2009) and two adults ringed in May 2010 (Guernsey) and June 2010 (Burhou, Alderney) respectively. The other colour ringed Lesser Black-backed Gulls originated from:-

 Iceland (three), Norway (31), Germany (six), Denmark (four), The Netherlands (32), Belgium (19), France (seven), England (17) and Wales (two).

 The only other colour rings read were on Audouin’s Gulls (Spain 29), Mediterranean Gull (Poland one) and Yellow-legged Gull (Spain one).

 ACKOWLEDGEMENTS

The gull studies would not be possible without the valuable financial support of the project sponsors who cover much of the costs of the colour rings, metal rings and the transport costs for the field work in the Bailiwick. The principal sponsor in 2010 has been the Channel Islands Co-operative Society Ltd, with further valuable contributions from La Société Guernesiaise, La Société Sercquiaise and the local branch of the Royal Society of the Protection of Birds.

 A small but dedicated team of ringers and assistants throughout the Bailiwick has helped to complete the field work. In particular Catherine and Sophie Veron, Chris Mourant and Jamie & Mish Hooper provided valuable help, as did Jen Stockdale in Alderney.

 The cannon netting sessions make a huge positive impact on the gull projects, and once again I am deeply grateful to Paul Roper and members of the North Thames Gull Group for coming over to Guernsey and working so hard (in difficult conditions) to make the 2010 campaign a success. In this regard a large debt off thanks is also due to the landfill staff and management who were essential to the success of this operation. Thanks also to the landfill operators and staff for giving me free access to the landfill, and assistance with my gull studies there throughout 2010.

 Gull research in the Bailiwick is simply not possible without the help of several expert boatmen who land us on the colonies and rocks, and in this regard I am grateful to Roland Gauvain (Alderney), Andy Cook (Sark) and Dave Perrio (Guernsey). My sincere thanks to the owners/administrators of the islands and islets visited as part of this research – including the States of Guernsey, the States of Alderney and Dr Peter Ogden (Jethou).

 Margaret Austin has the unenviable task of keeping the official records for the Channel Islands Bird Ringing Scheme. The scale and success of the gull research has resulted in a very large increase in workload for her, which she has taken in very good cheer. My thanks also to Carole Kinnersly for her many hours spent regularly updating the Herring Gull databases for me. I am also very grateful to Helen Wain and Charles David for their work in preparing the gull databases for ready transfer to other more suitable computer programmes.

 Finally such research projects rely heavily on a loose network of enthusiastic amateur gull watchers and recorders scattered across Western Europe. Many of these observers commit hundreds of hours every year to observing, recording, photographing and reporting colour ringed gulls. I am extremely grateful to all these birders for enhancing my gull studies with their reports of “Guernsey” gulls!!

Paul K Veron

Channel Islands Bird Ringing Permit No 129

 21 January 2010

APPENDIX - Selected Movements of Guernsey Gulls in 2010