www.gull-research.org

Rings Caspian Gull from Minsk.

Hi Dmitry,







Should be good to have some birds trapped at the nest I think. Here in Holland, Roland-Jan Buijs uses walk-in cages, maybe you know, maybe not. I'll try to explain here: 1. see drawing. You make a cage with a door that opens to the ceiling inside the cage (use tie-wraps). The door of the cage must swing easily. To keep the door open, you attach a fish-line at a bottom of the door and lead the line via the ceiling back into the cage. At the end of this line (line B in drawing) is a paperclip. Cut one of the iron wires on the lefthand fence (5 cm above ground level) and bend this iron wire just a little bit outwards. Fish-line B + paperclip should have a length to put the paperclip on the bended iron wire, and keep the door pointing towards the ceiling.

Now, we only have to make another fishing-line (line A) from right to left, exactly the width of the cage, with another paperclip at the end (paperclip A). This line A is used to set in train the process. So, take paperclip B from the iron wire, and now put paperclip A first on the wire (!!!!) and then paperclip B.

The idea: a bird walks around the cage to find the door, and doesn't touches the door with its head. While walking in, it pushes forwards fish-line A, but automatically also pushes forwards paperclip A. Paperclip A is pushed from the bended iron, taking with him paperclip B. Now the fish-line B is released and the door falls down. Bird trapped.

2. if there are chicks, don't catch adults.

3. take some boxes / sacks to carry gulls to a location to process them.

From where I live, the phenotypic features of the birds breeding in your area are bewildering. This is probably more true as you wrote you also find hybrids between argentatus and cachinnans. I think the only way dealing with ID for these birds is trapping adults at the nest and do measurements. Just in case you like to know what we have done in a mixed colony in Holland, here are a few photographes.

We scored the upper-part grey tone and primary moult score of each bird in the field.



Always pictures of: Upperwing full spread also showing greater primary coverts, underwing full spread, legs with rings and head in profile were all photographed. This allows the images to be examined afterwards in Photoshop (CS2) to characterise each bird according to 11 features:

1. Grey tone of upper-parts. Scored 1-20 on Agfa grey scale (which is similar to the Kodak 20 step grey scale) in 0.5 classes. Scored in the field, and checked on the computer.

2. Black on greater primary coverts. Scored as either present (+) or absent (-). A bird is scored positive only when pigmentation exceeds the width of the shaft. For birds of the argentatus group this is an indication for immaturity. If necessary, we also photographed the tail and secondaries with immature marks.


3. Number of primaries with black pigmentation. Small black sub-terminal spots are included and scored positive.

4. P10
5. and P9 primary patterns.



6. P5 primary pattern.

7. Red gonydeal spot on upper mandible.

And also:
8. Black on lower and upper mandibles.

9. Iris speckling. We used 6 classes. 0: No speckling. I: Speckling < 1% of surface. II: Speckling 1-5%. III: Speckling 5-10%. IV: Speckling 10-20%. V: Speckling > 20%. We did not score so-called ‘clouded’ irides, as true black values are not present in such iris markings. See plate 2 for example of birds in each class.



10. Orbital ring colour. Three classes. I: Yellow (ffff00-ffa800 on colour scale in Photoshop). II: Orange (ff5800-ffa800). III: Red (ff0000-ff5500).

11. Primary Moult Score for left wing (ranges from 0-50). Following Stewart (2006), we use six classes. 0: Old feather. 1: Missing feather, new feather in pin. 2: New feather visible, < 1/3. 3: New feather, 1/3 – 2/3. 4: New feather, > 2/3, but still waxy sheath. 5: New feather fully grown.

12. Measurements of "head + bill" and wing.

And finally, last point but maybe I should have started with this: it's good to have a small team working together. This makes the process of ringing quicker, you have a person doing the writing and photographing, and at quite moments, people can scan the roof for metal / plastic rings with a telescope.
Maybe there is a faculty of Biology at Minsk university? It's a lot of work if you have to do it all by yourself!

The gull (cachinnans or hibrid?) with a metal ring L002095 from Ukraine was noted in a mixed colony on the roof of a building in Gatovo 05/06/2013.

Hi Dmitry,
Excellent work again! Did you manage to construct the cages and did the paperclip thing worked out? Hope you get that LBBG bugger!
This Kiev ring is cachinnans, without question, on location.

Hi Mars,
The trap is now ready and I hope to catch gulls.
All the best
Dmitry

Aah, exciting period of ringing. Would be nice to see the results. Hope you will have some support from (university) students to help in the process. If you use the cages, please stop trapping birds after hatching, when they have chicks.
You can start trapping when nests have 3 eggs, otherwise they are maybe anxious to enter the cage. Here in the Netherlands we have postponed trapping as the season starts very late in 2013. Still only a few eggs by 10 May!!!!

Interesting, this year I found micha chick big enough for plastic ring on April 18th:) It is the earliest one for me..