pecking order / bathing order

When I first noticed this bird bath there were three birds bathing in it: a bluetit, a blackbird and a collared dove. 

When they noticed me, the bluetit and dove quickly flew away, the blackbird continued to bathe. 

When I managed to get my camera ready, the dove flew back, and the birds indulged in this staring match.

Just after I took this photo, the blackbird flew away.