Dave Houston, Author at Conservation blog

Tagging yellow-eyed penguins on the Otago Peninsula

Dave Houston — 20/02/2013

Dave supports biodiversity programmes anywhere between Auckland and the Auckland Islands, but specialises in the Chatham Islands and penguins.

Using a band or ring has been vital to the monitoring and conservation of birds for more than 100 years. Yellow-eyed penguins were first fitted with leg bands as part of a landmark population study by schoolteacher-biologist Lance Richdale in the 1930’s.

A flipper-band on a yellow-eyed penguin

Unfortunately, leg bands proved to be difficult to read and also caused some injuries so, by the late 1950’s, flipper bands became the standard for marking penguins.

The current banding programme for yellow-eyed’s started in the 1970’s and has enabled the monitoring of penguin survival (to a ripe old age of 24 years) and allowed researchers to know the age and history of the individuals at the focus of their research.

Flipper bands are not without problems. They decrease the underwater efficiency of the bird and, particularly if poorly fitted or maintained, can cause feather wear and injury. Alternatives to bands have been explored and one under investigation at the moment is the use RFID tags of the same type used in dogs and cats. While safe and long-lasting, they do have the downside of requiring electronic readers to find out if a bird is marked and who it is.

Yellow-eyed Penguin Trust staff inserting a RFID tag into a penguin chick

Whichever method used, it is important to ensure that those applying the tag are doing so correctly in order to minimise the risk to the bird and maximise what we learn as a result. Penguin chicks get tagged just before they go to sea and I recently took the opportunity to join DOC staff, Yellow-eyed Penguin Trust and Massey University Veterinary students and oversee the tagging of this season’s batch of chicks on the Otago Peninsula.

Ranger Mel Young showing Wane Begg and Jim Fyfe the best way of measuring head length

Assisted by volunteers willing to crawl through flax, gorse and nettle, we visited several sites, going to nests found earlier in the season, before locating and capturing the chicks. Bags are used to restrain the birds while they get weighed, measured and tagged before being released back at their nest site. The weight tells us how good the food supply is (5-6 kg is the normal range) and measuring the head and feet of the chicks gives us an indication of the sex – the males are slightly larger.

Volunteer Monika Fry with penguin chick ready for weighing

Also along for a day was Jeff Corwin of “Animal Planet” fame, filming for the third series of “Ocean Mysteries”. Jeff, trailed by his camera crew, enthusastically crawled through the shrubbery, helping capture and measure chicks. Later in the day he assisted researcher Dr Thomas Mattern with the retrieval and deployment of GPS/dive loggers attached to the parents of some of the chicks we tagged as part of a long-term project looking at where the birds feed.

Ranger Mel Young talking penguins with Jeff Corwin

The opportunity to assist with this work, and spend a few days on the beautiful Otago Peninsula in no less than spectacular weather, was very much worth the being stung by nettle, scratched by gorse, bitten, beaten and pooped on by penguins.

Dr Thomas Mattern and Jeff Corwin waiting for a GPS-fitted penguin to return

Postscript

Since my visit some 57 adult yellow-eyed penguins on the Otago Peninsula have died suddenly, possibly due to a marine biotoxin. Birds found dead on the beach have been identified by their tag, enabling rangers to locate the nest and keep a close eye on their almost-fledged chicks. Understanding how the penguins encountered the bio-toxin will be helped by the GPS and dive logger data.

Yellow-eyed penguin foraging tracks. Credit: Dr Thomas Mattern

In Native animals, Otago bird banding, Otago Peninsula, Yellow eyed penguin

Yellow-eyed penguins on Codfish Island/Whenua Hou

Dave Houston — 06/11/2012

By Dave Houston

Declining nest numbers

Juvenile yellow-eyed penguins loitering on Sealers Bay beach in 2001

Waaaaay back in 1981 I encountered my first yellow-eyed penguin on Codfish Island or Whenua Hou. 20 years later I was back on Codfish with DOC colleague Dean Nelson and David Blair of the Yellow-eyed Penguin Trust (YEPT) as part of the first ever census of yellow-eyeds on Stewart Island and its outliers. While the numbers found on Stewart Island were alarmingly low, things on Codfish looked good with 61 breeding pairs and more than 40 juvenile (1-year old) birds seen.

A ‘classic’ yellow-eyed penguin nest under a rata tree

Eight years later Dean and I went back to Codfish with Sandy King of the YEPT to see if the decline in penguin numbers on the Anglem coast of Stewart Island was mirrored there, we took the best cooler with us fulled with goodies. A week of searching revealed only 46 pairs, down 25% on the previous count. We also saw no juvenile birds, an indication that poor food year had reduced the survival of the young birds in their first year at sea. To be sure that this was not just a temporary blip in a bad year, Dean and I again went to Codfish and searched for nests in 2011. Again, no juvenile birds were seen and nest numbers had dropped further to just 39 pairs.

This year Dean is back on Codfish on his own to see if the trend is continuing.

Finding penguins

Supplejack tangle: There’s a penguin in there somewhere

To the uninitiated, counting penguins seems like ‘a walk in the park’. Instead it can be a dirty, frustrating and physically demanding task. Yellow-eyed penguins nest in forest, ususally with their backs to a tree or in dense vegetation and up to 500m inland. Finding them means starting at their landing point and following the often subtle signs of a penguin track, ocassionally dotted with tell-tale penguin poop. Unlike us somewhat taller humans, penguins have no trouble negotiating the thick vegetation and seem to take delight in detouring through the thickest supplejack patches on the way to their nests, sometimes necessitating a hands and knees approach. The smell of seabird poop can alert the searcher that a nest is nearby and then close inspection of all likely looking hollows and thickets is required.

Once found, the nest is checked for eggs, the attending bird is checked for a flipper band or transponder and the nest marked by GPS and flagging tape so that the nest can be revisited later in the season to determine breeding success.

What’s going on?

Dean checking a nesting bird for a transponder

Yellow-eyed penguins are long-lived (Dean just found a couple of birds he banded as chicks 20 years ago) and Codfish island is predator-free, so why isn’t it a penguin paradise? Despite good breeding success in most years, first-year survival of penguins can be very low in years when food resources are low. It seems that Codfish has experienced several of these poor years in recent times, meaning that few young birds have survived to enter the breeding population.

While adults are safe on their island sanctuary, at sea they are vulnerable to predators (mainly sharks) and by enganglement with nets set for rig and elephant fish (species most often encountered in your fish-and-chip shop). The extent of this at-sea mortality is not well understood.

And in news just in…

Dean has just emerged from the bush having found 39 nests, no change on last year (read his search dairy here). While not great news, it does confirm that last year’s low count was not a ‘one off’ low count and that something is really going on here. The continued absence of juvenile birds suggests ongoing unfavourable marine conditions. Hopefully next year’s count will start to show a positive trend.

Yellow-eyed penguins at sea

In Native animals, Southland Codfish, penguin, Stewart Island, yellow-eyed

Wandering albatross chick on Chatham Islands

Dave Houston — 24/10/2012

Antipodean wandering albatross chick atop Hapeka on Pitt Island

By Dave Houston

Remote Ranger

For 5 years Kenny Dix was DOC’s ranger in New Zealand’s most remote community – Pitt Island. Situated 25km south of Chatham Island, the 6,000 ha Pitt Island is home to around 30 people – and one pair of Antipodean wandering albatross.

Now working on the “big smoke” of Chatham Island, Kenny recently took the opportunity to return to Pitt to band the wandering albatross chick atop Hakepa, one of the islands high points. This is the sixth Antipodean wandering albatross chick to be raised on Pitt Island and the fouth for the Hapeka pair. Taking almost a full year to raise, this chick will hopefully fledge in January and commence wandering the Southern Ocean. It may be up to 10 years before the chick settles down and breeds for the first time.

Northern Antipodes?

As the name suggests, the primary home of the Antipodean wandering albatross are the Antipodes Islands, some 700km to the south. Having visited the Antipodes myself, I can see why Hakepa’s windswept plateau, tussock and fern vegetation and magnificent views seem like home to the albatross.

Kenny with one of the proud albatross parents

Southern neighbours

Another pair of albatross at the Southern end of Pitt produced a chick two years ago, however failed to return this year to breed. We’re hoping that they might show up next year so than Kenny can keep up his banding skills.

Pitt Island

In Chatham Islands, Native animals Albatross, Chatham petrel, Chathams, Pitt Island

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