In 2018, together with the ringer Jesús Fernández and his colleagues and helpers from GOSUR, the investigations on the colony of barn swallows on the Dehesa San Francisco in Santa Olalla del Cala (Huelva), Andalusia started in 2017, were continued. The year before, 19 adults, 5 fledglings and 20 nestlings could be marked with rings from the Spanish central office for ringing in Madrid.
In 2018, the ringing was started one week earlier than the year before. Less breeding couples were registered compared to the year before. Due to the earlier date, the fledglings had not yet hatched. Only 13 adult swallows could be ringed. It was interesting to observe that several of the adult ones ringed in 2017 came back to their old breeding place. We could manage to identify 4 of the adults marked in 2017 at the same nest. The year before, the adults weighed an average of 0,6 grams more; fat and muscle values were the same.
