West Coast Blue Penguin Kororā Tracking Project – report from the New Zealand Penguin Initiative (NZPI)
October saw the resumption of the blue penguin – kororā tracking project on the West Coast that began in November 2019 and follows earlier efforts by the West Coast Penguin Trust (WCPT) to track blue penguins. The current project, a collaboration between NZPI and WCPT, will provide long-term foraging data of blue penguins -kororā from two colonies in Charleston, Buller District. This at-sea monitoring runs in parallel with the nest monitoring programme to give a more complete picture of the drivers of breeding success while building a general understanding of how the birds use the local marine environment.
Two rounds of deployments were completed with GPS dive data being attained for a total of eleven breeding birds – seven individuals in the earlier chick-guard stage and four in the later post-guard stage. Birds were fitted with GPS dive loggers (55 x 25 x 12mm; 20g) at the nest and devices were retrieved in the subsequent nights following considerable surveillance, either at the nest or between the landing site and the nest.
The seven chick-guard birds showed similar foraging routes, all focusing in an area to the west-northwest of the two colonies, travelling around 20 km offshore (14.1-23.5 km), covering about 50km per foraging trip (47.7-56.9 km) and diving to around 9 m (mean dive depth for individual birds: 6.1 – 10.7 m). All birds tracked during the chick-guard stage completed single day foraging trips.
Of the four post-guard birds tracked, three completed 2-day foraging trips with one staying at sea for three days before returning to the nest. These birds generally foraged in the same area as the birds tracked during chick-guard, to the west-northwest of the two colonies. The exception being one individual that travelled almost 40 km west-southwest, although this appears to be overnight drifting while resting at the surface. Analysis of the dive data is still pending.
The body condition of the study birds and their chicks indicated that there was ample prey availability in this foraging area throughout October 2020 and the fledging success rate of 70.4% suggests that conditions have been good throughout this season, a change from the previous season when chicks were dying from starvation.
NZPI developed an online dashboard for the WCPT to view and share the foraging information and associated summary statistics (www.penguindb.nz/WCPT/tracking).
Kororā tracking protocols and facilitation of nation-wide tracking projects
The NZPI is continuing to develop best practice guidelines for kororā tracking. Next year they will support more community groups with tracking projects as they work towards their long-term goal of conducting and facilitating tracking projects covering all regions of New Zealand.
Dr Thomas Mattern, Scientific Advisor and leader of the NZPI explains:
“The project with WCPT provided a useful lesson for us by further enforcing the notion that successful deployment and retrieval of loggers can require intensive effort and strategy, far beyond that required for nest monitoring. During the work on the West Coast we observed birds departing the colony and going to sea in the middle of the night, which was surprising as kororā are generally thought to depart in the lead up to dawn. We repeatedly observed breeders in the chick-guard stage return to the nest at night and for their partner, who had been guarding chicks, to depart almost immediately. Similarly, we observed breeders in the post-guard stage returning to the nest between 10pm and 3.30am and feeding chicks for 10 minutes before departing again. GPS and dive data showed that these birds would head out to sea and rest on the surface until day break before commencing foraging.
“This behaviour has significant implications for the logger deployment and retrieval effort as constant surveillance of each nest is required to intercept the birds. Over the post-guard period, Trust Ranger, Matt Charteris, Richard Seed (NZPI Research & Conservation Coordinator) and Trust Scientist Kerry-Jayne Wilson covered the hours of 9.30 pm to 3.30 am at the nests in order to retrieve the loggers.
“This should not deter community groups from undertaking tracking projects as the importance of at-sea monitoring is paramount for effective conservation, but its important to understand the time commitments and intensive effort that is sometimes required to deploy and retrieve loggers.”
While materials were chosen that would stand up to the harsh coastal conditions, those same coastal conditions are conducive to plant growth! Occasional checks of the fences have been carried out by volunteers and rangers so that any maintenance needs can be identified and remedied. The never-ending need for maintenance is managing the vegetation that can grow through the fence, for example gorse, blackberry and hydrangea, pushing it to breaking point in places, or flop over causing damage from the weight of rank grass, rushes and weeds such as montbretia.
Volunteers recently spent a few hours tidying up the main fence along Woodpecker Bay north of Punakaiki so a big shout out to them - thank you Fiona, Jony, Reef, Katrina, Mandy, Marty, Teresa and Deb! Flax had been pressing down on the fence, but now the fence has been freed up by these wonderful volunteers - and they picked up a fair bit of rubbish too.
Volunteer Natassja Savidge has offered to check and help maintain the Hokitika penguin protection fence and joined Ranger Lucy Waller and Manager Inger Perkins in May to inspect the length of the fence. Some minor issues were found but the main finding was the extent of the vegetation growth that was damaging the fence in places. Big thanks to Natassja!
