Aug 24, 2011

18 year old Herring Gull

This evenings quick visit to the park in the city centre of Bergen gave us the opportunity to put plastic ring on our oldest Herring Gull (Larus argentatus) this year. We first saw it standing a bit outside all the first and second year Herrings and got really interested when we saw it was ringed on right foot instead of the left. Alf Tore Mjøs who has done a lot of the ringing in Bergen in the end of the 1980's and 1990's always put the ring on left foot. In addition the ring look like it was quite old due to wear. After some time we got hold of it and and gave it a black plastic ring with JN707 inscription. We did all our measurements and took standard pictures of wing and head. The excitement was high when we opened the Ring Access program and punched in the number and the result said that it was ringed as a pullus in 1993 in Valderøy, Sunnmøre which is 240 kilometres north of Bergen. A bird ringed as a pullus makes it even more valuable.
The bird was ringed at Valderøy 22.06.1993 240 kilometres north of Bergen.

P10 and P9 are unmoulted and from last year. P8 (not showing on picture), P7, and P6 are growing. The first secondary have also been renewed. A moulting score of 60%.

Head of our 18 year old friend.

We also did a nice reading of a Herring gull ringed with white JA ring. Large gulls ringed with JA was the first color ringing project in Bergen. This JA39 was ringed as a 1Y in 18th of March 2004.

Aug 23, 2011

Finally a 1Y Lesser Black-backed gull

Christian ringing the Lesser Black-backed gull
This evenings tiny catching effort gave us the opportunity to once again touch and ring a Lesser Black-backed gull. It was caught  at one of our regular places south of Bergen at Tveitevatnet. We equipped it with JC1K, measured it and wished it good luck for it's journey to the Mediterranean. In addition we also ringed a 1Y Mew Gull making the total number for this species 40. We also read five of the Mew Gulls from the weekend knowing that they still were fattening up for their migration southwards.

Lesser Blacked-backed gull JC1K's wing

Aug 21, 2011

This years first 1Y weekend

1Y Mew Gull. Do not scream with food in your mouth
When the weather forecast for the weekend said cloudy and rain showers we decided to go for a weekend catching 1Y gulls. Despite several interesting football matches in Premier League we choose gull catching (!) just following the matches on our mobile phones. Primarily we tried to achieve our goal of catching one hundred 1Y Mew Gulls before end of September, but if a Herring or Lesser Black-backed gull comes to close we will of course also grab these. Friday evening started will with six Mew Gulls and one Herring gull in just over one hour. Saturday was even better, but we only had a window of approximately two hours to easily get gulls. After the sun burst though the clouds and loads of people, dogs and children occupied the best places to catch. The gulls became more and more 'thick-necked' and less and less eager to come close to us. The day ended with seven Mew Gulls and two Herring Gulls. On Sunday we woke up to fully clouded sky and rain. This weather really make the gulls easy to catch and in the end of the day we had ringed 16 Mew Gulls and 2 Herring gulls.

We also did one interesting reading when we saw a 1Y Mew Gull we marked in an suburb area north of Bergen in the city centre of Byparken. The distance is only about 10 kilometres, but it is interesting to know that gull hatched in the suburbs make their way to the city centre to feed before migration starts. The marked increase of 1Y gulls in the city centre the last week may therefore be birds form the areas surrounding Bergen (both suburban breeders and 1Y's form breeders in natural habitat) and the urban gulls form the city centre.

J2R8 moving from the suburbs to the city centre of Bergen

Our first 1Y weekend gave us these results:
Species1YSub adult
Mew Gull263
Herring gull41

JN703, a big 1Y male Herring gull was one of our results this weekend

Our total number of 1Y Mew gull is at the time of writing 39 individuals. This includes one ringed as pullus which later got plastic.

Ringing summary for July 2011

J7Y0 nests on top of the physics building at University of Bergen.
In July we concentrated the effort of catching as many adult gulls as we could. Most of them were Mew Gulls (Larus canus) since these are the easiest species to catch. However, we also used many hours of trying to get as many adult Lesser Blacked-backed Gulls (Larus fuscus intermedius) as well. These are of special interests because they have become urban breeders in the city centre of Bergen. We first observed this nesting strategy in 2007 when one pair nested on the Science building at University of Bergen. This year the number of roof-breeding Lesser black-backed gulls (LBG) is probably closer to 20 pairs. The problem with LBG's is the time needed to catch one individual which our July number of this species indicate. On the other hand none urban breeding adult LBG's has ever been ringed in Bergen and to get information on survival and future breeding behaviour can be very interesting! The first Black-headed Gull was ringed on the 26th of July two weeks after the first individual arrived. See the blog post The black-headed gulls are back.

Our numbers for July are as follows:
Species1YSub adultAdult
Mew Gull1728
Lesser Blacked-backed Gull107
Herring gull021
Black-headed Gull010

We will come back with a blog post on our readings and controls later.

Aug 20, 2011

The winter Mew Gulls are back in Bergen

J800 arrived at Tveitevatnet 08th of August.
Photo: Eirik Nydal Adolfsen
The first of our regular winter Mew gulls (Larus canus) was seen at Tveitevannet 08th of August. J800 was ringed 24th of February 2004 as a 2Y and is therefore in it's 9th year now. The bird has been seen every winter in the Bergen area except for the winter 2009/2010. It probably breeds north or east of Bergen. The arrival date this year concur with a period when the adult Mew Gulls are migrating.

The adult Mew Gulls breeding in Bergen also seems to have migrated. The adults we ringed in late May, June and to about 10th of July were not regularly seen after 25th of July. On the 10th of August we visited one of the breeding colonies north of Bergen (Kvassnesstemma in Knarvik) a locality where we have done some catching this year. Here we did not find a single adult bird, just 1Y's and a few 2Y's. They all seems to be gone south! We hope to get some sightings of these individuals this winter in Great Britain or The Netherlands.

Aug 6, 2011

Ready for the 1Y Mew Gulls

The last days more and more first year mew gulls have started to show up in the city centre of Bergen.  To not be short of rings we used the friday evening to make 100 new plastic rings. The process is quite easy and the pictures below show how to do it.

The plastic plates when they arrive from engraver.
To be able to roll the plastic we put them in hot boiling water
The rings are rolled by hand

After the ring is put into a metal pipe and then put back into boiling water to get the right shape. A stick which fit the inside of the ring it put though the metal pipe and the plastic ring. 

When the ring has the correct shape put it in cold water
Then the rings are perfect for a mew gull legg.
The finished product...

Aug 4, 2011

The natural born sparrow killer, J8Y3

Lesser Black-backed gull J8Y3 born on a roof in the middle of University of Bergen campus
When reading literature the main food source of Lesser Black-backed gulls (Larus fuscus) are fish. A study by Bustnes et. al (2010) found that saithe (Pollachius virens) and herring are the most important food sources of chicks. However gulls are regarded as generalists and will take advantage of every kind of food that are available. This is probably an important factor for their success as urban breeders.

This individual (J8Y3) was born at the roof of VilVite centre at Marineholmen in the middle of Bergen city centre. When it was close to fledge it jumped off the roof when some workers did some maintenance on the roof. Down on the ground it was an easy target for us and we ringed it the 14th of July but gave it poor hope for survival as it did not seemed frighted at all.

Four days later we found it some hundred meters away in the park. When we feed the other gulls with bread it it took some pieces but then suddenly it grabbed a young House sparrow (Passer domesticus) held it in the beak until it was dead and swallowed it in one go. We believed this to be of pure luck mostly since this is a young and inexperienced individual.

Some days later we experienced exactly the same. When we feed breed in order to read a metal ring on a Black-headed gull we heard the death screams from House sparrow and then saw the Lesser Black-backed young standing with it in it's beak. It took under a minute before the pour sparrow was dead and it could be swallowed in one go. This time we quickly got our camera equipment form our bags and took some shots and video.

This prove the ability of these beautiful gulls to be generalists and take advantage of every food source available. This bird which we first thought had small chances for survival will hopefully be reported from Anza, Agadir in Morocco in one of the following winters.