Cassiobury Park - 25.8.11

A brief spell of sun this morning encouraged c.20 House Martins to swarm together looking for insects but soon the rain arrived and stayed for over 3 hours! Around 10 RN Parakeets were seen and heard and the long staying Chiffchaff called away by the river. However the strangest sight was of 2 adult Green Woodpeckers that were on the ground about 3 feet apart and they were swaying their heads from side to side and slowly getting closer and closer until they were infront of each other. They then threw their heads back and forth gently touching the tips of their bills together. It was like watching the display of White Storks and Gannets and I don't know if it's display, aggression or pair bonding? Anyone ever seen anything like this before?!