Is it normal for so many birds to congregate together?

QEvery evening, since mid-spring, we’ve noticed a huge collection of Blackbirds/starlings (we’re not sure) out the back of our flat. There has to be around 1,000 birds that congregate every evening. They always fly into the trees around some allotments where there are berries but don’t regularly feed. Is this a common event? I have attached a few photos taken through binoculars for you. Lee Jemma

AThey’re Starlings, many of them juveniles, and it’s common for this species to gather in large flocks from midsummer onwards – such gatherings usually reach a peak in autumn and winter, when they perform ‘murmurations’ – co-ordinated flights prior to settling down for the night. The birds gather for protection against predators (on the safety in numbers principle), and perhaps to exchange information on good food sources, with the young birds following the adults the following morning. Bird Watching editor Matt Merritt says: “I have a similar thing going on in a large tree near my home at the moment, although on a much smaller scale. Up to 100 Starlings gather every night, and up to 40 come into my garden and use the feeders – they’re going through five or six fat balls a day.