This year swallows ( house martins ) arrived much later than normal. I noted this on another posting. They arrived en masse together with a lesser number of swifts and not one single sand martin.
So quite a bit later than usual there they were wheeling around although not so many nested in the town this year.
The significant thing is they have practically all disappeared a month earlier than usual. Flamingos usually in flocks on the wetlands between La Marina and Santa Pola. I have not seen one on my frequent trips to Alicante.
The most common cause mooted is climate change. I have lived in Spain these past twelve years and apart from the mid winter period (which seems to have become a bit colder) i have not noticed any significant climate change.
A similar population pattern in the insect world. When I first came to live in Spain there were many varieties of butterflies and moths on the wing. I have not seen one single butterfly for two years now.
I do not believe these reductions are due to climate change. I believe spanish agricultural practices are responsible; particularly the use of pesticides. My guess is sterility has happened to any survivors.
If !! I am correct in my supposition; the thought occurrs; not only what am I absorbing; what are consumers in other countries who purchase spanish produce consuming ? In my case virile potential has absented itself. On this latter point I have not the least concern. What does concern me is the imbalance and absence of species in many ecological areas.
Studies ( not lessons to be learned ) have become increasingly urgent year on year.