Identifying color rings of lesser black-backed gulls

[damianooldoni]

Lisenka:

Voor de kleine mantelmeeuw is het onduidelijk over welke zwarte ringen het gaat. Er is op cr-birding.org geen Belgisch project te vinden met zwarte ringen bij kleine mantelmeeuwen en ook in het crbirding_birds bestand dat je hebt opgestuurd kan ik geen zwarte ringen terugvinden.

[damianooldoni]

To Lisenka: I don't understand why you speak about black rings. I don't see any black ring (letter N) linked to lesser black-backed gulls (euring code: 05910), only blue ones (letter B), e.g. BW(NC.AD) I can see in our data that the most recent lesser black-backed gulls have blue rings. with white inscription and that the inscription:

1. is 4 characters long
2. doesn't contain any number, only letters
3. the third letter is A or O

I see that another rule holds true among the oldest, changed rings. Among these ones, I see a lot of rings where the third letter is B. @EricStienen : Is this the right rule among these rings? Moreover, there are 94 old rings containing numbers: EL52, PR3, E373, B50, R7. TY2, E099, 735N, EX07, EL06, NR0, TY8, ...
And I see also other exceptions (?) like this one: BABP.

[EricStienen]

All rings that contain the letter B at the third position are "virtual rings". These birds originally had a colour but died before they could fledge and the colour ring was reused on another inidvidual. Since it is of utmost importance for our calculations of survival that the dead birds remain in the database, they received a non-existing code.

The 94 old rings with an abberent coding are all old rings of foreign projects. In fact these are no longer relevant as these individuals now wear a blue BE-ring. The old rings can no longer be read and thus not reported. They should, however, remain in the system but only as former ings.

[damianooldoni]

@EricStienen : thanks for your advice. I did it. The remaining rings (153 rings) can be divided in three categories:

1. color rings with numbers (96 rings)
2. color rings with a B at third position (50 rings)
3. rings not satisfying condition 1 or 2 (7)

In attachment the three lists of rings. I hope this can help with solving this issue.

rings_color_still_unknown_with_B_third_pos.txt rings_color_still_unknown_with_number.txt rings_color_still_unknown_left.txt

[EricStienen]

As I already thought. All rings of group 1 and 3 are omdat foreign rings that were replaced by a blue Belgian 4-letter ring with either an A of an O in third position. group 2 are all virtual codes.

[EricStienen]

As I already thought. All rings of group 1 and 3 are omdat foreign rings that were replaced by a blue Belgian 4-letter ring with either an A of an O in third position. group 2 are all virtual codes.

[damianooldoni]

@EricStienen : I will assign to virtual rings same color as others lesser black-backed gulls, i.e. blue ring and white inscription, BW(**B*). I also add a note virtual_color_ring for these rings. Do you agree? Tackling the old foreign rings will be done after I do this.

[EricStienen]

OK to make the virtual rings Blue with White inscription.

[EricStienen]

I would suggest to leave the colours of group 3 empty (NA). It is not relevant because theydo not wear the old ring for a long time and have a new BLUE BE-ring. Only the blue ring can be reported by an observer!

[damianooldoni]

@EricStienen : and what about group 1? Actually this conversation should return to the right issue, #84, so please answer there :smile: Thanks.

[EricStienen]

BW(*B) are noted as virtual_color_ring rings. This is an option, but you might maybe better opt to leave them out of the database.

[damianooldoni]

Thanks @EricStienen for your suggestion. I will see if I can remove them without disrupting the reference ids of the birds. Maybe I can remove them at the very end. I will see. I have to check it. If it gets complicated I will not remove them.