We were on the Top Bridge Trail that starts from the industrial park in Parksville. We probably had not covered more than half a kilometre when we saw a large, very long winged mainly white bird fly right overhead. The wings were really long, slender and pointed at the tips. The head was all white with a yellow bill and some black at the base of the bill. The head and neck stuck well out in front and the tail projected well out the back so that the wings appeared to be positioned about halfway along the body. It was clearly not a gull or tern and seemed at least as big as a Glaucous-winged Gull, likely bigger. The under sides of the wings were mainly white with some duskiness along the trailing edge and out towards the tips. I don't recall what the tail looked like. I think I was too focused on the head. The flight was strong and direct. Eight or ten flaps and it was gone out of sight. We never saw the upper side of the wings or back because the bird was almost directly overhead. It was also not very high, perhaps twice treetop height. My immediate reaction was to say gannet. Then I thought oh oh gannets don't occur here or on the Pacific. To me it had to be a booby. X who has never seen a booby of any description said that he had never seen any bird like that. When I got home and consulted the books I found that I could immediately rule out gannet, black wing tips and wrong bill colour. But Masked Booby has the right bill colour, black at the base of the bill and mostly white under the wings. If you look at page 54 of the large Sibley you will see at the top right of the page a string of four gannets in flight. X and I agreed that that is exactly the profile we saw.