A group of three of us visited the lagoon on Tuesday 16th April. We spent an hour from 10-11am observing any birds on and in the vegetation area adjacent to the lagoon.
List of birds observed (some extra to the photos included in the observations posted):

Welcome swallows +
Blackbird (female) 1
Greenfinch 8
Goldfinch + (at least 2 dozen)
NZ Pipit 2
Mallard duck 2
Paradise shelduck 2
Rock pigeon 8
Skylark 3
Black-backed gull 1
Black shag 5
Magpie 1