Two distinct waves of synchronised breeding occurred at a colony of Great Cormorants Phalacrocorax carbo in west Scotland in 2007. The second wave led to young fledging in September, exceptionally late for this species locally. Evidence from elsewhere suggests that this second wave was not double-brooding (raising of two broods in one year by the same pair) but breeding by newly-arrived birds that had failed at a nearby colony earlier in the year.