That is one of the hopes of SETI and I would contend it has been pretty much falsified. We've listened long enough for beacons - there are none for kiloparsecs. We are alone or They are doing something better than turning on petawatt beacons.

Just like we see no Dyson-spheres for hundreds of light years we also 'see' no beacons - Scientific American summarised that data a few years ago. James Annis has also shown that no spiral galaxies in a fair sample exhibited signs of being wrapped in Dyson-spheres by a Kardashev III civilisation either. This sort of data is telling us something - either They don't exist or They don't expand to Galactic Empire size over billennia as some SETI optimists had assumed.

Adam