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The initiative has aimed to know the movement patterns and evaluate the population reinforcement strategy of a critically endangered species such as the marbled teal (Marmaronetta angustirostris) through:

• The evaluation of the population reinforcement strategy.
• The determination of the use of the space during the reproductive period and prior to migratory movements and the identification of dispersal and wintering areas.

• Field monitoring of captive breeding specimens released within the population reinforcement program of the Generalitat Valenciana and the Junta de Andalucía within the framework of the National Strategy for the Conservation of the Marbled Teal.

• Analysis of the positioning data of 11 specimens equipped with GSM/GPS transmitters from captive breeding within the population reinforcement program of the Generalitat Valenciana.

• Tracking of specimens equipped with GSM/GPS transmitters for a full year from release.

The project developed by theMiguel Hernández University of Elche has had the purpose ofKnow the movement patterns and evaluate thepopulation reinforcement strategy of a critically endangered species such as theMarbled teal (Marmaronetta angustirostris). The initiative has had the support of the Biodiversity Foundation of the Ministry for the Ecological Transition and the Demographic Challenge, through its call for grants.

One of the actions that have been carried out has been the field monitoring of the captive breeding specimens, which were released within the population reinforcement program of the Generalitat Valenciana and the Junta de Andalucía, within the framework of the National Strategy for the Conservation of the Marbled Teal.

This action was carried out in the Natural Park of El Hondo, where aintensive work to search for specimens, as well as the rest of the surrounding wetlands in the south of Alicante. From the beginning, intensive monitoring has been carried out to know the number of individuals of the species present in the study area. To this end, the following were arranged: camera traps in strategic places that allowed the alphanumeric code of the specimens located on the PVC rings they carry to be read.

The entity has also used the capture-recapture method to be able to make estimates ofannual survival, calculating thatit is currently 0.47 with a standard error of 0.15. Similarly, the reproduction has been verified in specimens that were released in the months of February and March 2019, since it was verified that they had used the nest boxes that were provided for this purpose.

An analysis of the positioning data of 11 specimens equipped with GSM/GPS transmitters from captive breeding within the population reinforcement program of the Generalitat Valenciana was also carried out. This action was carried out in the wetlands of southern Alicante. The entity tagged with GPS/GSM-GPRS transmitters to, on the one hand, increase knowledge about the patterns of use of space and dispersive movements, and, on the other, to objectively assess the survival of the specimens and the causes of mortality.

During 2019, a total of 15 birds were tagged, 12 of them from the captive breeding project and three wild specimens. Thanks to this, it has been possible to obtain positioning maps of the birds marked during the breeding season, the DANA event, and the hunting period.

After this action, the geolocated specimens were monitored for a full year from the release. This has led to the conclusion that the survival of the specimens is high until the end of the summer, since a high percentage of the released individuals were still in the protected area at the end of September. From October onwards, the loss of specimens began to be confirmed, some of them due to natural causes such as predation and in the case of at least two specimens the death of illegal hunting. Hunting activity appears as a cause of unnatural mortality both in the Doñana area and in the El Hondo Natural Park, nuclei of the breeding population.

It is also found that none of the specimens tagged with emitters that did not leave El Hondo survived. In addition, this action was able to determine that the wintering area of the specimens released in the El Hondo Natural Park is located inAlgeria, since the four tagged specimens that left the peninsula sent positions from that country.

The study has also provided data on the existence of clear differences in the wintering areas of the population of western Andalusia and that located in Levante. According to the research, the Alicante specimens are preferentially directed to Algeria, more specifically to wetlands located in the northern area of the Sahara desert, while the population of the Doñana seems to winter inMorocco.