Titipounamu, NZ’s tiniest bird

The best-known Māori name of the rifleman (Acanthisitta chloris) is titipounamu. The titi probably refers to its squeaky, high-pitched call and the pounamu to the green colouring of the males. You can see this striking colouring if you look closely at this photo, as the tiny bird’s back and head pretty closely match the colour of the surrounding beech tree leaves.

Another Māori name is momo-tawai, which means ‘beech tree species’. The riflemen photographed for this story were part of a fairly large group (regiment? company?) hanging around in the beech forest on the track to the Mt Arthur hut, in the Kahurangi National Park.

It’s the green head and back of the male rifleman that gained the species its European name. British rifle regiments wore dark green uniforms with low-visibility black insignia, and this tiny New Zealand forest bird reminded 19th century settlers of a rifleman’s garb.

The rifleman is one of New Zealand’s smallest birds. Weight-wise, it’s about the same as the grey warbler; males are 6 grams, females around 7. But lengthwise the rifleman is definitely the smallest, at 8 cm compared to the grey warbler’s 11 cm. The rifleman packs as much weight into its 8 cm frame as the grey warbler does into 11 cm; yes, your average rifleman is quite rotund. The grey warbler gets some extra length from having a longer tail, whereas the rifleman’s tail kind of gets lost among its wingtips when it’s sitting on a branch or rock.

The female rifleman is slightly larger than the male, by a gram. Females also have different colouring, lacking the green back and shoulders.

As you can see in the photo above, the female is more brown and speckled. Sometimes, when seeing a rifleman from below, it can be difficult to tell whether you’re looking at the male or the female. This one’s a female, you can just see the brown speckling on the top of her head.

Riflemen feed exclusively on insects. They browse native forests, going up and down trees, systematically hunting down their tiny prey. This rifleman has taken an interest in what’s inhabiting the mosses and lichens on the underside of a branch.

Both the male and the female have this pearly-white chest and belly, along with the fierce white eye stripes and the yellow sweat stains under their wings.

This somewhat unusual angle shows off the rifleman’s pearly white belly, not to mention its acrobatic skills.

Young birds are more mottled on their chests, and the pearly chest and white brow seem to come in as the birds mature. This rifleman is possibly a young female; she still has a bit of speckling on her chest and her white eye stripe isn’t very strong.

Riflemen are monogamous and the male and female will stick close together throughout the year, even outside of the breeding season. Older offspring will stay near the parents and help out with the feeding of chicks in later broods. This is why when you’re in the forest and hear the high-pitched zeet-zeet of the rifleman, it’s rare to see just one. They’re calling to each other, keeping in touch, as they search up and down the forest trees for insects.