BirdStrike.
You are correct, all internal flights to from Tenerife are to the north airport. However it is well worth the 40-60 min drive to sit through the approach. Last time I did it, it was over the hills about 8-10k once over the airfield a long spiral with what felt like close-up views of the hills. Ending in low level over the houses untill touch down. Definately non standrd. Maybe they where just having a bit of fun