Gulls

Yellow ring without code (on tibia) and metal ring (on other leg). 

note 1 : these birds were ringed during a GPS tracking study in the Ebro Delta during spring 2011, as a collaboration between SEO/BirdLife and Barcelona University, supported by the Ebro Delta Natural Park.

note 2 : some 60 birds were taghed, some of them already carrying a PVC ring, and the rest ringed with metal ring and one colour ring (either yellow or orange). These rings have been used to avoid interfering in the monitoring study carried out by IMEDEA (Daniel Oro et al.) in the colony, at their request.

note 3 : the aim of using identifiable (colour) rings was to easily spot the tagged birds at the moment of recapture for tag retieval (2 weeks after first capture). Although it implies losing information, we assumed that these rings would not interfere any other ringing scheme intended to study seabird movements away from the breeding colonies, as such studies would use either darvic rings with a code or a combination of colour rings.

note 4 : all birds were not recaptured and some of them left the colony with the GPS on. In case somebody reports a trapped bird carrying one of these devices, please let the projectleader know as to recover the information.