Hen and Chicken Island weeding

Weed control on Northland's largest offshore nature reserves commenced in 1993 on the near-pristine Poor Knights Islands, and two years later on the majestic Hen and Chicken Islands to protect the islands' high natural values.

Weed control initially aimed at eradicating five invasive weed species: Mexican devil (Ageratina adenophora), Mistflower (A. riparia), Moth plant (Araujia sericifera) and two pampas species (Cortaderia jubata and C. selloana).

Hen Island

Island weeding field trips

The field season for island weed control is during the drier, warmer months of September through April. The island weed team supervisor leads his team on 10-day trips every fortnight.

During the 2011/12 season, the island weed team consisted of three full time staff members and several volunteers.

Finding and treating weed sites

The team searches for new sites and checks existing ones. All weeds are hand-pulled.

Known weed sites are displayed on a map and a GPS unit, so the sites can be found easily. In the 2011/12 season, the team managed to treat the majority of the known weed sites, found and treated several new sites, and carried out searches of previously unexplored areas.

Abseiling is part of the job on the Hen
and Chicken Islands

Working in challenging terrain

The terrain on the islands is tough - a long walk every morning and evening just to access the sites and get home. Very steep slopes, craggy bluffs and rock faces create daily challenges, so ropes come out and it is abseiling time! This is all part of the job: no weeds are safe from the island weeders!

Progress of weed control on the islands

Although the team is still pulling high numbers of adult plants (mainly Mexican devil), far higher numbers of juvenile plants are being removed, which is showing some progress in the control of this plant.

The main species now found on the Hen and Chickens are

Mexican devil

• Mexican devil,
• Mist flower,
• Moth plant,
• Pampas,
• Cape gooseberry,
• Smilax,
• Mexican daisy
• Purple groundsel

All of these weeds can be removed by hand or shovel. If they are in seed, we remove the seed heads to reduce their spread, and we hang the uprooted plant from tree branches to allow desiccation.

The team keeps a tally of weeds removed each season, and so far, the numbers are decreasing.

Monitoring the effectiveness of weed control

To find out how the native plants and weed species are filling in the areas where weeds have been pulled, photo point monitoring will begin during the 2011/2012 season. This involves setting up photographs from an exact location, and each time a site is revisited a new photograph is taken, so over time the regeneration patterns can be seen.

The trips were successful in the 2011/12 season; we are slowly but surely controlling the infestations. With any luck, the hard work that the weed team put in will make the job of future teams a little easier.

A unique island experience

Not many people get to enjoy this unique experience. Start your day hearing the dawn chorus of thousands of native birds, seeing tuatara scuttling around in their natural habitat, kaka coming to see who you are, and saddlebacks telling you that they can see you.

The evenings are filled with fishing, snorkelling or just resting tired legs on the beach with a drink and a tub of muscle rub whilst the sun sinks over the hills.

Then the sea birds come home for the night with their eerie calls and 'kamikaze' dives through the canopy before finding their burrows or the top of your tent.

And ready for the same the next day! Who would not want to get their hands dirty to experience this?

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