Hi Juan, where are you from? I'm one of those from Bilbao. I live at Algorta (Getxo) (15 km from Bilbao), my father, grandfather, and the father of my grandfather were all from Bilbao (we don't remember any more ;-).
Here Search Engine Databases say that Alday people are from: Getxo, Ceanuri, Gordexola, Berriz (1601 year), Orduña, Oñati (1646 year), Bergara, Amurrio, Arceniaga, Ayala, Okondo, Concepcion (Chile) (1685 year). All villages from Basque Country except Concepcion (Chile).