Drought reduces the value of both artificial and natural wetlands for gulls breeding in the Mediterranean region

Increasing water extraction and climate change combine to increase the impact of droughts in Mediterranean wetlands. Natural wetlands are being increasingly transformed into artificial wetlands, notably ricefields and aquaculture ponds. Since waterbirds are highly dependent on aquatic resources throughout their life cycles, changes in wetland habitats can significantly affect their use and movements. Studies relying on count data can highlight the importance of artificial wetlands for waterbirds, but analysis of movements using GPS tracking data facilitates a full assessment of their value compared to natural wetlands. We used GPS-tracking to study the habitat use of nesting black-headed gulls, Chroicocephalus ridibundus, in the iconic Doñana wetlands in Spain. In this area, the flooding of remaining natural wetlands has been reduced by overextraction of groundwater and by prolonged drought, whereas adjacent fish ponds have maintained stable water levels. We tagged 65 adults, and studie..., , # Drought reduces the value of both artificial and natural wetlands for gulls breeding in the Mediterranean region

Dataset DOI: [10.5061/dryad.k3j9kd5n2](10.5061/dryad.k3j9kd5n2)

## Description of the data and file structure

This dataset contains the GPS fixes of 24 black-headed gulls with nesting attempts inside our study area. BHGs were captured under licence with a clap-net (ECOTONE, Poland) placed > 2 km from breeding colonies in VLP and were deployed by GPS/GSM transmitters (OMNI-2G loggers, Druid Technology Co) in 2022 and 2023 in VLP. Devices were programmed to take GPS fixes every 10-minutes (day) or 30-minutes (night) with boost function activated. Boost provides more GPS fixes (every 1 minute) if the device has a full battery.

### Files and variables

#### File: Tracking_data_of_nesting_black-headed_gulls.csv

**Description:** 

##### Variables

* ID: Unique Identifier
* longitude: Longitude of the GNSS fix in degrees, accurate to 7 decimal places
* latitude: Latitude of t..., ,