Suwarrow is for the birds

Wednesday June 06, 2018 Written by Published in Environment
The Te Ipukarea Society team pictured on Suwarrow. 18060302 The Te Ipukarea Society team pictured on Suwarrow. 18060302

The team from Te Ipukarea Society has recently reported in by satellite phone from Suwarrow, where they are hard at work in a very labour-intensive exercise to eradicate the island’s rats once and for all.

The TIS team consists of Alanna Smith, Mary McDonald, Mia Samuel and Kelvin Passfield. They have been joined on Suwarrow by Ashley Cota, a volunteer from the Pacific Islands Conservation Initiative, and Suva-based Steve Cranwell, invasive species programme manager from Birdlife International. National Environment Service rangers Harry Papai and John Samuel are also providing much appreciated support.

This exercise marks the third attempt to remove the invasive rodents from the Suwarrow atoll since 2003.

The last baiting was in 2013, and at that time rats were successfully removed from Anchorage, the main motu where the NES rangers are based, and also where the visiting yachts anchor. Unfortunately, a few survived on Motu Tou, and these have now increased to the maximum carrying capacity for the motu.

It is thought that one of the reasons the 2013 operation on Motu Tou failed is because of the very high numbers of coconut crabs there that love eating the rat bait.

To counteract this, the team has now more than doubled the amount of rat bait used in their operation, in the hope that there will be plenty for both the crabs and the rats.

Crabs are totally unaffected by the rat bait, although it is recommended that humans do not eat the crabs for at least six months after a baiting operating such as this.

The TIS team left Rarotonga on Saturday, May 12, and overnighted on Palmerston on Tuesday the 14th, where they were very well looked after by the Marsters family. They finally arrived in Suwarrow on Thursday, May 17, along with the NES rangers.

After a full day of unloading their cargo on the beach at Anchorage Island – including 188 buckets of rat bait totalling nearly two tonnes in weight – the team overnighted on Anchorage.

They slept in a variety of accommodations, none of which you will find on Booking.com. These ranged from the old ranger house and the newer cyclone shelter to a few hammocks hanging between coconut trees on the beach.

The following day most of the team’s gear was loaded into two boats (the team boat and the NES boat) and transported to Motu Tou to set up a base for the rat baiting.

Based on information received from the rangers, the team surmised that Motu Tou was the only motu with rats remaining.

That same day the team also started to cut through the thick island vegetation to establish a reference line through the motu along the east-west axis of the islet.

The next day the reference-line cutting was completed and the team started cutting the baiting tracks across the motu in a north-south direction.

After six days’ worth of hard labour, accompanied by numerous wasp stings, the cutting of the tracks was completed – 31 parallel tracks in all, each 25 metres apart.

During this period rat traps were also set on the two small motu (Kena 1 and 2) next to Motu Tou, to see if any rats had made it across to these islets.

Much to the team’s disappointment, rats were trapped on both motu, meaning more track cutting for a seventh day so that these motu could also be baited.

Several trips were also made back to Anchorage to collect half of the rat-bait buckets for the first round of baiting.

The next step was to mark baiting points at 25-metre intervals along each track, eventually resulting in 301 points marked in a grid across all three motu.

The reason for the 25-metre grid-point system is to allow a person to stand at each bait point and throw bait in a circle around them out to a distance of approximately 12.5 metres, in an attempt to achieve 100 per cent coverage of the motu.

In theory, this means there shouldn’t be any small pockets where rats might possibly miss out on their fair share of the bait.

Once the baiting points were all marked, the team was at last ready to carry out the actual baiting.

The first round of baiting finally occurred over the Friday and Saturday of May 25-26, and the team returned to the luxury of Anchorage, where they had showers with a bit more than a two-litre teapot of water per person.

The weather turned out to be in favour of a successful operation, with no significant rainfall for four days after the baiting.

Rain is not good as the bait deteriorates much faster, and also the rats tend to be less active in heavy rain. This was also a possible factor in the failure on Motu Tou last time, as there was heavy rain one day after the baiting occurred.

The TIS team will provide a further update on their operations when they can. Meanwhile, they are waiting 10 days before a second round of baiting on Motu Tou and the two Kena Motu. During this time they are carrying out bird surveys around the atoll.

The team would like to thank the Cook Islands Global Environment Facility Small Grant Programme for providing much of the financial support for this project, along with Birdlife International for their further technical and financial support from the David and Lucile Packard Foundation and David and Sarah Gordon.

            - Release/SB

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