One every thousand nests !

Photo by A. Sanz-Aguilar

We have probably measured eggs and the clutch size of more than one thousand nests since 2007, when we began monitoring  the Yellow legged gulls at the Natural Park of Sa Dragonera. This year, for the first time we found a nest with 5 eggs. Most likely a case of egg dumping. 

Happy easter!

New publication on marine Turtles!

Heredero Saura, L., Jáñez-Escalada, L., López Navas, J., Cordero, K. and Santidrian Tomillo, P. 2022 Nest-site selection influences offspring sex ratio in green turtles, a species with temperature-dependent sex determination. Climatic Change 170, 39 (2022). DOI: 10.1007/s10584-022-03325-y

 Abstract: Climate change threatens species with temperature-dependent sex determination as further warming could result in extremely biased sex ratios or offspring of only one sex. Among the possible adaptations of sea turtles to climate change, are behavioral responses toward nesting in cooler areas. We analyzed nesting patterns of East Pacific green turtles (Chelonia mydas) in Costa Rica to determine the occurrence of nest-site selection and how this could influence primary sex ratios (PSR). Green turtles exhibited nest-site repeatability. Nests placed by the same individual were generally closer (mean distance: 237.4 m) than other nests on the beach (mean distance: 411.0 m) and this repeatability was maintained in different nesting seasons. 

Photo from www.fisheries.noaa.gov

Additionally, turtles tended to place late nests closer to each other than their early nests, suggesting an adjusting nesting behavior throughout the nesting season. A great majority of nests were placed in the vegetation (80.9%) and within this zone, turtles preferred nesting under trees (78%) than in grass areas (28%), where temperatures were cooler and PSR were less female biased. Mean nest temperature (°C) during the thermosensitive period and mean PSR were 30.7 ± 1.2 °C and 79 ± 4%, respectively. Most years were female-biased or extremely female-biased but there was approximately one male-biased year in the decade. Although many nests produced 100% females, some male hatchlings were produced every year, even during the extreme 2015–2016 El Niño event. The preference of green turtles for nesting in shaded areas could help to mitigate the negative impacts of climate change unless temperatures in shaded areas rose above the male producing temperatures.

 Press releases in Spanish here and here

 

 

ERASMUS+ with the GEDA-i !

Sofia Bolumar Rosa, from the "Dipartimento di Scienze della Vita e Biologia dei Sistemi" of the University of Turin is joining out team within the frame of the ERASMUS+ program. She will be working on the ecology of seabirds and join our fieldwork activities in the Balearic Archipelago. Welcome Sofia!

First time in Africa!

For the first time since 2016, one Yellow legged gull marked with GSM/GPS has visited Africa. It might be a consequence of the transformation of the open-air landfill occurred last year. These animals do not stop to surprise us!

 

Balearic Shearwater 2022 campaign !

The GEDA-i took the relay of the work done last year monitoring the nest of the Balearic Shearwaters at Dragonera Natural Park. 

Photo: ©Pep Arcos

The Balearic Shearwater is an endemic seabird of the Balearic archipelago and among the most threatened species in Europe.  We hope to provide information on the current status of the Balearic Shearwater in the Park, that can be used to set management actions.

Yellow-legged gull 2022 campaign !

Photo: M. Gomilla

 The Yellow-Legged gull 2022 campaign just began. Marked birds are already preparing to breed at the colony. We are warming up the engines to record the demographic parameters for this year.

 

 

GEDA at the 11F !

 

Today GEDA joined the activities for the International Day of Woman and Girl in Science. More information here, here and here

 

 

 

Seabirds on the news!

Photo: Victor Paris

 J.-M. Igual wrote an overview of what we know about seabirds, what has been done and about the actions that should be undertaken for their conservation. He resumes in few lines his thirty-year experience working with these amazing birds. Read the full text (in spanish) here