Hi Miles2go,
Until last year, I could have said that I had walked all over Spain on a lot of different Caminos every year since 2000 and had never had ticks. Then last year, walking from Bilbao to Ponferrada on the Camino Olvidado, I got them several times, even while wearing long pants and a long sleeved shirt. The places were rural, somewhat hilly/mountainous (near Vilasana de Mena, near Cistierna, and once near Cervera de Pisuerga). Other people reported ticks, too, on other Caminos.
See this thread:
https://www.caminodesantiago.me/community/threads/ticks-on-camino-frances.27915/#post-228459
I think some people said that the numbers of ticks last year had to do with an unusual amount of spring rain, but I can't swear to the truth of that. All I know is that I had never heard or seen of them till last year! It may still be too early for them, I don't know.
Buen camino, Laurie