New publication on gulls and landfills!

Delgado, S., Tavecchia, G., Herrero, A. et al. Model projections reveal a recent decrease in a yellow-legged gull population after landfill closure. Eur J Wildl Res 69, 99 (2023). https://doi.org/10.1007/s10344-023-01723-w

 In a shell: The study reveals that the closure of local landfills leads to a decline in survival rates, especially in younger birds, ultimately causing a population decrease with continuing consequences.

Abstract: The food available in open-air landfills, one of the most common predictable anthropogenic food subsidies (PAFS), can have a profound impact on animal biodiversity. Understanding how and to what extent PAFS affect wildlife is crucial for a sustainable management of resources. Most large gulls behave as opportunistic foragers and constitute a good avian model to analyze the effect of PAFS reduction on animal populations. 

Using individual data from a yellow-legged gull population of the Basque coast (northern Iberia) collected over a 15-year period, we estimated survival and reproductive parameters and used them to parameterize an age-structured population model to explore the effects of the local landfill closure. Local survival probability declined with time as a consequence of the progressive closure of the local landfill sites. The top-ranked models included a quadratic function of time, suggesting an acceleration of mortality during the later years, especially in juveniles, while survival in adults was linear. An effect more pronounced in first year birds than in older birds. Population models predict a decrease of the population and confirmed a greater sensitivity of the population growth rate to adult survival probability. Overall, our results suggest that the reduced carrying capacity of the system resulted after landfill closures have caused a population decline which is expected to continue in the near future.

GEDA at school !

In the Balearic Archipelago, the Yellow legged gulls commonly visit schools to clean the patio from the leftovers of their mid-morning snack. This cleaning service can be an opportunity for the children to familiarize with a species adapted to exploit remains produced by human activities. The GEDA in collaboration with the CEIP Son Oliva and OCEAN NIGHT began a didactical project where gulls become teachers. 

 

Through their ecology and movements, students will learn the marine ecosystem and the role of seabirds as bridge between ocean and land.

 

We have first introduced the species (left) and ask student to count how many gulls visit the school each day.

We than equipped two of these gulls with a GSM/GPS transmitter  and follow their activity through an online platform (below).  In June, once the gull breeding period ends, we will meet the student again and discuss what gull taught us about their life and the ocean.

YLG 2023 field campaign, just started!

The Yellow-Legged Gull 2023 field compaign at Sa Dragonera Natural Park has started. 

Birds are looking for a territory. We are looking for red rings. Gull B5TX is already near its nest. 

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!

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!

 

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.

 

 

Citizen science at Sa Dragonera Island! Saturady 24 April.

Do you like wildlife photgraphy? Suscribe for the Red Ring Challenge here and join our long-term research on the Yellow-legged gull at Sa Dragonera Island.

Take a picture of a marked gull and win an original T-Shirt. 

Presence-absence data of marked animals are extremely important as they can be used to estimate annual survival probability and movements of individuals within the breeding colony. 

The project, funded by the Spanish Ministery of Science and Education, will investigate how the management of discards from human activities influences the ecology of gulls. 

To subscribe write your name and telephone number to:

medgulls@gmail.com

 

 

 

Gulls in Ibiza! If you are resident on the island, join the investigation!

Yellow-legged gulls are perceived by some as "bad" and "dangerous" and considered a nuisance. For others, the species is simply fulfilling its role of predator and generalist forager as do other species, such as cats. The GEDA has launched an investigation in Ibiza to assess the perception of gulls by the general public and help to mitigate potential human-wildlife conflicts.

If you are resident in Ibiza, you can join the investigation here at

http://viis.abdn.ac.uk/snapwebhost/s.asp?k=159895186855

For more information on the enquire, read the new press release here

Prospecting..?

After a summer in the Alicante region, the Yellow-legged gull "G_1394" came back to its colony the 24th of January. Few days later it returned to Alicante. Is this a prospection or the gull found something wrong with the colony and move to Alicante to breed ?  The prospecting behaviour is still poorly studied but increasing evidence suggests it is more common than previously thought. Stay tuned to know what "G_1394" will do in early spring.

Yellow-legged gull y COVID-19

Photo: Emil Colom Arques

The breeding season of the Yellow-legged gull is ending. Impossible to conduct a full campaign with the anti COVID-19 measures.

RED RING CHALLENGE subscriptions open !!

Do you want to help our research?

Try your skills in making pictures of moving animals. Take pictures of gulls with red rings with readable codes and win prices. 
More info here

 14 March 2020, 9h45 St Elm Port

To subscribe send your name and telephone number to:

Gulls' summer vacation : a new route to the Atlantic!

Gulls began to move north to colder waters (or better landfills).The Ebro route is confirmed, but one gull showed us a new route to the Atlantic !!! Something we have suspected in the past but never proved : the route Narbonne-Toulouse-Bordeaux.

Yellow-Legged Gull campaign 2019!

Yellow-legged gull campaign on the starting blocks! It will be our 13th year and looking forward to see how the gulls did this year.

Master on Marine Ecology with the GEDA

M. Martin Perez

A. Sola

M. Martin Perez and M. Castell from the University of the Blearic Island, and A. Sola from the University of Santiago began their Final Work (TFM) for their Master Degree on Marine Ecology with the GEDA.

M. Castell

 Maria will be focussing her research on the response of Cory's Shearwater to climatic changes, Marga will experimentally evaluate the recruitment behaviour of Storm Petrel and Alfonso will study the foraging strategy of the Yellow-Legged Gull. They will be supervised by A. Sanz-Aguilar, G. Tavecchia and J.-M. Igual.
Their respective fieldwork campaigns are on the starting blocks !