Bird Wave ....

.... is a term for a mixed-species foraging flock.

We have one of these that progresses around our property made up of long-tailed tits and bluetits. Today a chiffchaff seemed to be tagging along. I enjoyed watching them preening, playing and feeding as they spent a long time in one dying elderberry bush being taken over by brambles. Africa Gomez explains the advantages to the birds of this behaviour in her wonderful Rattling Crow blog. http://therattlingcrow.blogspot.co.uk/2013/12/treecreepers-and-mixed-flocks.html

It seems that our flock is made up mainly of young birds. They stay together through the autumn and winter for the mutual benefits and split up in the spring when they pair off to breed.