Belfast Lough may be nestled between gentle hills to the north and south, but its sheltered, shallow waters are far from tranquil. This cold slice of the Irish Sea funnels directly into Northern Ireland’s iconic capital and hums with activity 24/7. Its surface is crisscrossed with ferries, cargo ships, fishing vessels and pleasure craft and its shores are alive with walkers, dogs and birdwatchers. It really is all go–go–go.

Prior to 2011, we knew very little about what our breeding Cuckoos did once they left the UK for the winter months.

BTO’s Head and Principal Ecologist David Noble breaks down what we really mean by ‘invasive species’.