"They are found wherever there is a large body of water and plenty of food," he said.
"They feed mainly on fish, but also crustaceans (shrimp), insects and other aquatic animals."
Only time would tell if the birds had moved in permanently and would breed, but sightings were becoming much more common than in the past.
Only a handful of sightings had been reported in New Zealand in the last 125 years, including the Whanganui River (1890), Kaipara Harbour (1976), Southland (1977) and South Canterbury (1977-78).
Three pelicans seen on the Waitemata Harbour in January were thought to have been part of a flock of 18 that were seen together at Tapora, on the Kaipara Harbour, in April.