Gull Research Organisation 

(last update: 04 oktober 2005)


Ruud Altenburg, digiscoping 1cy michahellis in Amsterdam, July 2003.  


Cooperation in SW Netherlands in the 1990’s

In the late 1990’s, three bird-watchers in the SW Netherlands independently specialised in gull research. Theo Muusse focussed on Lesser Black-backed Gulls at Maasvlakte and Dintelhaven colonies, not far from his home town Dordrecht . Mars Muusse, who worked as cook in a restaurant at IJmuiden beach, regularly checked resting gull flocks right in front of the restaurant and breeding Herring Gulls in the IJmuiden fishing-harbour. Bert-Jan Luijendijk, from Oud-Beijerland, very regularly visited the Scheveningen harbour to study moult sequences and timing in Herring Gulls and travelled to the south of the Netherlands to study cachinnans.

These three gull enthusiasts soon cooperated in their studies. Preliminary results were discussed, research goals were set and they elaborated long nights on observation methods and statistical analyses. After many evenings and night, with a bottle of red wine or a cold beer, they agreed on a priority list of field researches, methods and measurements. In 1998 and 1999, much time was spent on observing Lesser Black-backed Gulls at several locations along the Dutch coast: Mars at IJmuiden , near Amsterdam , Theo and Bert-Jan at Maasvlakte near Rotterdam . Adult and juvenile graellsii can be observed at close range in these colonies. 

Theo Muusse, scanning autumn gulls at 
Naaktstrand - Maasvlakte, the Netherlands. 

By autumn, resting groups were checked at Westkapelle. By that time, Pim Wolf from Vlissingen (close to Westkapelle) joined the group of three and Pim contributed enormously as he focussed particularly on ringed gulls at Westkapelle. Pim already had his website about graellsii at Westkapelle, illustrated with many of his pictures. This group of four bird-watchers continued research into the new millennium.

Launch of Muusse’s Website in 2000

Bert-Jan Luijendijk and Mars Muusse, counting michahellis at Etaples, NW France early August 2003.

Ruud Altenburg, preparing his 'picnic' at Etaples, NW France early August 2003.

The quickly growing data from the late 1990’s on graellsii and intermedius Lesser Black-backed Gulls culminated in the “Muusse’s Website”. This website was launched in January 2000. The approach was unusual for that time, as gulls were dealt with by calendar year and in sub-section by season. Every section was richly illustrated with digital photographs, a novelty by that time. Specific paragraphs returned in every section, including ‘characteristics, ‘moult sequence and timing’, ‘migration’ and ‘tables’. These tables showed the research results and statistics in detail.

In 2000, more interest developed to study gulls abroad and in January 2000 armenicus was studied in Israel . In summer, the first well-prepared visits to Le Portel, NW France were organised. Main focus was on moult timing in second calendar year michahellis, but all gulls were studied. Research was done under the name of FROG, the Dutch group for Field Research on Gulls.

Going abroad in 2001

Almost all months of 2001 were covered by observations of graellsii in the Netherlands , and most plumages were also digiscoped by Mars Muusse. He soon felt that a more detailed version of Muusse’s Website was necessary and also possible and much time was spent to write a month-by-month coverage of all plumages of graellsii, totalling 42 sections. In 2001, the new edition of this website was launched and called “Birdsnaps – Gulls of NW Europe”. The basis was laid for a similar month-by-month coverage of other taxa: argenteus/argentatus, marinus and michahellis.

Mars Muusse, ringing adult barabensis
in Bahrain, early March 2001.

Inspired by the success of the visit to Le Portel, we planned more visits in 2001: early May, late July, late September and early October. Interest in rare gulls also led to a short trip to the Arabian peninsular, when Theo and Mars Muusse studied and ringed barabensis, cachinnans, fuscus and heuglini in Bahrain , February and March 2001. The section ‘discussfus’ on the Birdsnaps website generated some debate and cooperation with Peter Stewart in the U.K. and Visa Rauste in Finland .

Focus on ringed 2cy michahellis in 2002

Pim Wolf at his local patch along 
the Dutch coast, Westkapelle, winter 2004.

Le Portel proved to be essential for close range observations of michahellis and throughout 2002 we planned visits to get a month-by-month coverage of michahellis: January, April, May, June, July, September, early October and late October. Some of the results of an identification article on 2cy michahellis were made public on the International Gull Meeting at Tampere , Finland . This trip was combined with a tour through S Scandinavia to check the contact zone of intermedius and fuscus.

After collecting data on post-juvenile moult in michahellis, autumn 2002 a new research on that subject was set up and focussed on ringed birds only. Simultaneously, this research was done for post-juvenile moult in 1cy Herring Gulls.

Norman van Swelm, ringing graellsii pullus at Maasvlakte, June 2004.

By 2002, sufficient data were collected for regression analyses on primary moult timing in 2cy herring gull, and research shifted to the partial autumn moult in 2cy herring gull, a subject not described yet. The last months of 2002 were spent in S France and N Italy to describe moult timing and sequences in ringed michahellis. Chris Gibbins, a Gull Meeting participant from Scotland helped with simultaneous researches on 1cy Herring Gulls and visits the Netherlands in November to study cachinnans at Westkapelle, Pim’s local patch. This month we organised the first Gull Evening, to show pictures and discuss results, of course with a good meal and a glass of wine.

Finally, December 2002 we get new support from Amsterdam , as Ruud Altenburg joint ORG.

Ringed adult graellsii in 2003

Ruud just joint the group when he visited Poland to study cachinnans, michahellis and argentatus at Lubna dump in May 2003. July 2003, Mars paid another visit to Finnish friends and Tampere dump again. Le Portel was in the picture again in February, March, April, May, June and August.

Fred Cottaar, ringer at IJmuiden harbour in Herring Gull and Lesser Black-backed Gull colonies. (summer 2005)

Two researches continued: data collection for the post-juvenile moult research in michahellis and the partial autumn moult in 2cy argentatus. November 2003 a special task force travelled to S France and N Spain to score ringed michahellis at the breeding grounds.

But an intensive new study was started as well: numerous visits were paid again to the colonies of Maasvlakte and Dintelhaven to score adult graellsii on primary moult commencement. We also visited the relatively new colony of Zeebrugge , Belgium several times in May and August.

All data were quickly analysed and put on the Birdsnaps website. We realised it would be better to first publish such data in magazines and it was agreed to withdraw the site. Chris Gibbins came to the Netherlands again and wrote his article on identification of cachinnans.

Ringing graellsii chicks in 2004

January 2004 just started when Ruud again visited Lubna dump in Poland again, now accompanied by Mars. They collected data for the post-juvenile moult in eastern Herring Gulls.

Roland-Jan Buijs, ringer of gulls in SW Netherlands. Here, in the Moerdijk colony, ringing and measuring adult LBBG.

This year, we continued to set up new researches, as we started a very intensive study on post-juvenile moult in graellsii at Maasvlakte. Over 200 chicks were ringed, measured, photographed and videoed, in cooperation with Norman van Swelm of the Bird Observatory Oostvoorne. Summer 2004 we finally put all information together on pre-breeding moult in 3cy graellsii and an article on this subject was published in Birding World in 2005.

Ringing adult graellsii in 2005

In 2005, ORG saw a new member again. Roland-Jan Buijs had been ringing adult and juvenile graellsii and argenteus at Moerdijk for several years. Theo contributed in this research and suggested data collection on moult and phenotypic characteristics. Roland-Jan and Theo published their data on the Bruxelles Colour-ring Meeting. Summer 2005, the first ORG article was published in Birding World.

Bert-Jan Luijendijk collecting graellsii pulli at Maasvlakte, June 2004.

Ruud Altenburg with hatched graellsii, May 2004. Tie-wrapped and measured for the 2004 juvenile graellsii project at Maasvlakte.

ORG: a new approach to gull research

From the very start of ORG, much emphasis was laid on descriptions of moult stage, timing and sequences. In the late 1990’s, this resulted in a feather-by-feather observation and score in gulls, and we do remember afternoon score sessions in the Etaples harbour, NW France, taking six hours or more in which we managed to describe just about 18 or 20 birds, especially when dealing with mid-summer 2cy michahellis. Most observers may feel it ridiculous to spend so much time describing such a small sample, and score every feather even if a bird is sleeping for a while. Nonetheless, these scoring sessions, in which feather tracts are divided in many sub-divisions have learned us a lot about moult timing and sequences and we believe introduced a new approach to gull-watching. In our approach, the scapular region is not a uniform area of feathers, but consists of small upper scapulars ( US ) and much longer lower scapulars (LS), and from a moult perspective, it is interesting to divide these areas again into upper and lower feathers, thus resulting in UUS, LUS, ULS and LLS. The LLS, the lower row of lower scapular include the long feathers also called scapular coverts, which may be moulted in different moult timing. A more detailed division also applied to the wing coverts: the lower lesser coverts were introduced in the classic division between greater coverts, median coverts and lesser coverts. Moult timing in this LLC row proved to more in line with median coverts. To score these feather tracts, uniform excel sheets were designed, which much contributed to the formalisation of data.

From 1999 onwards, most moult scores were supported by digital photographs, and up to 2005, we took over 75.000 images of gulls in only six years.

Chris Gibbins, video taping cachinnans in southern Netherlands. December 2003.

Theo Muusse with ringed graellsii at Maasvlakte, June 2004.

Ruud Altenburg, studying cachinnans and Scandinavian Herring Gulls at Polish rubbish dump, Lubna, January 2003.

Systematically scoring soon developed in detailed descriptions of moult amongst several gull taxa. However, it was difficult to make firm statements as origin and exact age could not be proven, and therefore we strongly focus on ringed birds nowadays. We also introduced standard colour scales and measurements for statistical analyses. This proved to be of great help and analyses can be executed fairly easily in Adobe Photoshop.

One of the first goals to achieve was simultaneous gull counts throughout Europe . In 2000, it seemed to be a nice idea to let gull enthusiasts throughout Europe introduce their research and do simultaneous surveys in several countries at the same day. This can be done for any species, for instance shape and extend of dark hoods in winter Black-headed Gull, primary moult scores in 2cy autumn Herring Gulls, orbital ring colour in local gulls of the argentatus-fuscus complex to name a few options. The idea was that participants from several countries systematically check their local gulls. This information is collected by the coordinator, processed and published. Such surveys can be executed about every month.

The idea has been tested only twice: to score second generation scapulars in Herring Gull in autumn 2002 and to score primary moult in 2cy michahellis in France , Spain and Italy in 2002.