It's an age old story renewed every spring - the season when the seldom-seen shining cuckoo's shrill, repetitive call pierces the chattering and singing of other birds.
"The shining cuckoo is a little bit late this year but you know spring has really arrived when you hear them. Sometimes you hear them from the end of September," Whangarei Native Bird Recovery Centre's Robert Webb said.
For at least two months, though, there has been frenzied activity in a sequence of bird life and bird death familiar to folk at the the centre. The season generally announces itself with a wave of heron chicks, the young wading birds' population and environment knocked around severely by moody, early spring weather.
"Little penguins, they've been coming in, too. It's been rough out there on the coast," Mr Webb said.
Then there's the fall-out - no, it's not a pun - from blackbirds, thrushes, starlings, fantails and other species. If any species demonstrates how tough is the law of the jungle, it's the tui.
"Vicious! You see the little blackbirds and thrushes sitting on the ground with a wound in their heads, dead? The tui's done that."
Tui don't like other species in the tree so other youngsters hopping from branch to branch before spreading their wings often get a fatal peck on the head, the proverbial king hit.
Baby birds on the ground often end up as dinner for harrier hawks (kahu) who do a good job of cleaning up nature's spills and kills. The recovery centre is hand-rearing a harrier chick at the moment - "A beautiful little bird," said Mr Webb. "Next month we'll start to get the baby moreporks in."
The 7-week-old hawk is the sole survivor of three chicks catapulted out of a flax bush being uprooted by a digger on a farm. It is only a quarter of its adult size, and surviving on a vitamin and mineral enriched diet.
Around Christmas time, wood pigeons will be among the 300 to 400 birds the centre deal with between now and the New Year, Mr Webb said.
Currently, kukupa (wood pigeon), tui and other sugar-addicts are feeding on blossoms and sweet new shoots but by Christmas they'll likely be getting drunk, feasting on the more potent fruits of summer. That's when people have close encounters with the big, fat, low flying and often disoriented kukupa (kereru), known for literally falling out of trees or crashing into window and cars.
In the meantime, nature is busy playing other tricks on birds. The iridescent green cuckoo (pipiwharauroa) returns to New Zealand after wintering in Pacific tropics. The female lays its egg in the empty nest of the tiny, blissful-voiced grey warbler who hatches then feeds a foster chick it is dwarfed by. Fortunately for the species, before the parasitic cuckoo arrives, the grey warbler's own offspring have already hatched, fledged and left.
"Nature's good like that," Mr Webb said.