The European turtledove (Streptopelia turtur) is smaller in build than other doves. They are migratory, which is also unusual for doves/pigeons.
They are critically endangered, their population has declined 85% since the 1970’s. The main causes are hunting in Southern Europe and the disappearing of nesting opportunities. There needs to be a reduction in the use of pesticides and adding nesting options. Of course hunting also needs to be forbidden, which they are working on (source: vogelbescherming.nl).