Guernsey Gulls March 2009
The year continued in very fine form, with much valuable data on Bailiwick gulls being gathered. The month was characterised by the return in force of our breeding Lesser Black-backed Gulls (Larus fuscus graellsii) from their wintering grounds, by the onset of courtship activity amongst local Herring Gulls (Larus argentatus), and by the dispersal of many of the Great Black-backed Gulls (Larus marinus) that had spent at least a part of the winter in Guernsey. It has been amazing to study these three species in March – all of which have revealed interesting aspects of their migratory and/or breeding ecology.
A great deal of effort has been made this month to visit Chouet landfill, and the beaches in the north of Guernsey, both to monitor the arrival of our returning Lesser Black-backed Gulls, and to record what was happening with our Herring and Great Black-backed gulls.
Over the month visits were made to look for colour rings at Chouet landfill and/or Pembroke, Chouet and Chouet landfill beaches on 28 days – resulting in a grand total of just over 500 ring reads as follows:-
Herring Gull 430
Lesser Black-backed Gull 64
Great Black-backed Gull 10
Lesser Black-backed Gull
Perhaps the highlight of a very interesting month for me was the re-sighting of another seven (making a total of nine so far this spring) out of 16 adult LBBGs that I ringed in my garden at Ty Coed, Guernsey in May/June/July 2008. Not one of these birds was present in Guernsey over the winter. The great value of colour ringing (over simple metal ringing) was demonstrated by the fact that of this tiny sample of gulls, two had been seen in Iberia over the autumn/winter period.
The return dates for these nine gulls were: -
14 February 7S5
20 February 7S6*
03 March 7S0 *
03 March 0Z1
07 March 7S1
11 March 7S3
11 March 7S4
19 March 7S2
23 March 0Z6
*7S0 had been seen on 22nd August 2008 at Meiras Beach, Valdovino, Spain by fellow gull enthusiast Antonio Gutierrez.* 7S6 had been seen on 21st August 2008 at Pantin Beach, Valdovino, Spain by Antonio Guteirrez, and at Matosinhos, Portugal by Peter Rock on 28 November 2008.
This sample is of course too small to be representative of adult survival rates, and there is time yet for more to be located. It will be very interesting though to see what the final tally will be. (P.S. 6S7 arrived back on 1st April, and 0.Z7 on 3rd April) – so we are now up to 11 out of 16 gulls back – only five more to find!).
4. Blue JU4A ringed as a chick near Mandal, Vest-Agder, Norway in July 2003, before being seen again in Vest-Agder in May 2005, Earsham, Norfolk, England in August 2006, in Rogoland, Norway in May 2008, before being seen at Chouet landfill on 28 March.
The movements of other Lesser Black-backed Gulls seen were less easy to interpret. In particular several that had originally been ringed as adults at the landfill sites near Gloucester, England, and which I had subsequently seen at Chouet, surprised me by re-appearing in Guernsey after several weeks’ absence. My suspicion that in most of the cases the birds had left Guernsey is backed up by the re-sighting of one of the birds back at Gloucester in the intervening period before it returned to Guernsey.
It will be fascinating to see if the birds below remain in Guernsey as the breeding season draws on. Perhaps they are in fact Channel Islands nesting gulls that have wandered north to winter in the UK, rather than English-nesting gulls that are using Guernsey as a staging post in their return migrations?
Although I have witnessed the spring return of Lesser Black-backed Gulls in Guernsey for several decades, I am embarrassed by how unobservant I have been in previous years. In 2009 I hoped to monitor the spring migration by making a daily count of LBBGs at Chouet (both in the landfill and on the beaches of Pembroke/Chouet and Chouet landfill Beach – all at the northern tip of Guernsey).
This aim has been severely hampered by the fact that I have so few of our local breeders colour ringed. It is therefore proving to be impossible to determine the proportions of locally breeding birds to passage migrants. An overall count is of some value, but I know that the few locally colour ringed birds do not all visit the area all at the same time. Their attendance can be spread over different parts of the day, and even over different days. I hope that by the spring of 2010 I will have a much larger sample of Bailiwick breeding adults colour ringed – thus making it easier to identify the proportions of migrants on any given day.
What is clear is that the numbers of LBBGs build very quickly from early in March. On 2nd March my maximum count was 90 LBBGs. This had increased to 120 birds on 4th, with 230 the following day. Numbers did not reach the 300 mark until 16 March, and by 21st 380 were counted. On 24th there were 400 LBBGs present, and the month ended with 450 birds present.
I had expected that the vast majority of LBBGs seen in Guernsey in the spring will be from the race Larus fuscus graellsii which nests (inter-alia) in Britain, Ireland and Iceland. Notwithstanding this, I was surprised at how few Larus fuscus intermedius I saw – in fact I was only convinced of seeing a single adult.
By the week commencing 23rd March, it was commonplace to see LBBGs in courtship behaviour – both on the beaches and in the landfill site. A few pairs were also observed copulating on 31st March – so the 2009 breeding season is clearly underway!
One final area of interest has been trying to read metal-ringed Lesser Black-backed Gulls. This is really a “mug’s game” because it is very difficult – and requires huge patience. Even when you can see the digits on a ring through the telescope, you have to be able to see all the way around in order to get the whole unique code. Notwithstanding this I am spurred on by the sight a reasonable number of adult Lesser Black-backed Gulls which carry metal rings. Over the month I managed to read seven Channel Islands metal rings, and they have given some valuable data for my projects. Of these birds two were originally ringed on Brecqhou, Sark in 1990 and 1994, while four were from Burhou, Alderney (1991, 1992, 1993 and 2006). All of these birds were ringed as nestlings. One adult ringed in the summer of 2006 in our garden at Ty Coed (one km from Chouet landfill) was also seen.
In addition I enjoyed the bonus of reading two British metal rings (one only partially, but the code is narrowed to a string of 100 rings – so it may at least be possible to know where this bird was ringed and in which year). Details for these two rings are currently awaited.
Postscript - details of the complete British ring read are as follows:-
London GG 67002 - Ringed as a nestling on the Isle of May, Scotland on 20/07/90 and sighted at Chouet Landfill Beach, Guernsey on 26/03/09 - a distance of 743 km south and a time lapse of 6,824 days.
With so much interesting activity taking place with Lesser Black-backed Gulls (my primary study species), it would have been easy to overlook what has been happening with Herring Gulls in Guernsey. Fortunately this has not been the case, and our Herring Gulls have revealed some interesting ecology too.
Having made regular visits to Chouet Landfill since August 2008, one might have expected that I would have recorded nearly all of the surviving Herring Gulls colour ringed by Jamie Hooper over the period 1998-2007. The sighting of 22 of Jamie’s gulls for the first time in March is strongly suggestive that these birds have been off-island at least since August 2008. Indeed the sightings history of some of these newly sighted gulls confirms this (see below –all were ringed as nestlings in June/July).
4. 6K6 ringed in 2003 and seen at Rogerville, Seine-Maritime, France in December 2003, before being seen at Chouet landfill on 5th March.
5. 3L5 ringed in 2002 and seen at Marais d’Olonne, Vendee, France before I saw it at Chouet landfill on 5th March.6. 4M7 ringed in 2003 and then seen in Bristol, England on 8th August 2003, and from 26th August to 12th September at Gloucester Landfill, England before being seen at Chouet Landfill Beach on 22nd March.
Pride of place, however, must go to the following two long distance travellers – both of which have spent time in Iberia before returning to Guernsey.
In addition to these movements I also recorded one foreign colour-ringed Herring Gull – from the south-west of England.
White G:C ringed as a nestling (female) in Gloucester, England in July 2007, seen from 6th to 11th March 2009 at Chouet Landfill, Guernsey, before being re-sighted at Gloucester landfill, England on 18th March.
Details were also received for the French-ringed Herring Gull seen at Chouet landfill on 26th February 2009. Pale Blue 113 was ringed as a chick at Le Havre, Seine-Maritime, France on 2nd July 2008. It was then seen at Trouville-sur-Mer, Calvados, France on 17th September 2008.
Again the colour ringing is making it possible to follow the lives of individual gulls in a very unobtrusive manner – revealing much fascinating information about their movements.
As well as these Herring Gulls, seen by me for the first time, it was also interesting to re-sight a number of birds which I had not seen since the autumn of 2008. Again, I believe that most of these birds will have left the island over the winter period, only to return now in the spring to breed.
In all I saw 172 of Jamie’s Herring Gulls during the month (418 sightings) , as well as 12 of mine (37 sightings) (ringed in late 2008/early 2009).
Great Black-backed Gull
As expected there was evidence of passage of Great Black-backed Gulls at the north end of Guernsey during the month. Until I commence my own colour ringing project on this species in the summer of 2009, it is impossible to follow the movements of local breeding population, as opposed to migrant birds. However, the further sightings of gulls originally ringed at Le Havre, Seine-Maritime and from the Chausey Islands, France backs this up.
In fact, it is interesting that a number of the French-ringed gulls were re-sighted in March- having not been seen in Guernsey for a number of weeks since their last sighting here (see below).
Blue 30C ringed at Le Havre, France in June 2007, and first seen in Guernsey at Perelle on 18 September 2008. I saw it several times up to 27 September, but there were no sightings over the entire winter period, before the gull was seen on ten occasions at Chouet between 10th and 31st March.
9th International Gull Meeting – Peterhead
I mentioned in the February Guernsey Gulls News that Catherine and I had been pleased to attend the 9th IGM at Peterhead, Scotland which had very kindly been organised by Dr Chris Gibbins of Aberdeen University. Unfortunately I have not been able to find a way to load my presentation on “The Changing Fortunes of Gulls Breeding in the Channel Islands” onto my web site. I can, however, include a photo of the participants.
Scarce Gulls in Guernsey
The only unusual gullsrecorded this month were an adult Mediterranean Gull on 1st at Cobo Bay, and an adult Common Gull on the beach at Pembroke on 19th.
© Phil Alexander
4th April 2009