Nesting Colonies of Vava'u's Outer Islands

posted by Kate Walker

Otu Motu Lalo outlined in red

In the early 1990s the three islands of Maninita, Taula and Lualoli (collectively known as Otu Motu Lalo) were proposed as a protected area by the Tongan government due to their importance as sea bird breeding colonies. Lack of resources and shifting priorities meant that this proposal was never taken any further. In the following years, Vava’u’s emerging eco-tourism market led to these islands being identified as potential tourist attractions and their importance was recognised by the New Zealand Overseas Development Administration funded Tongan Nature Tourism Program in 2002. As part of this program, a baseline survey of Maninita and Taula was commissioned and a rat eradication program was also carried out on both islands.

The baseline surveys, as reported by Dr D Watling from Environmental Consultants Fiji, list the species of flora and fauna that can be found on both islands and maps the ranges of vegetation habitat type. The dominant species of plant found on both islands is the tree locally known as Puko (Pisonia grandis), however their woodland type varies between islands. Maninita enjoys a high Puko tree forest with a solid unbroken canopy suggesting mature woodlands. Taula, on the other hand, is also mostly covered by Puko trees but the woodland is made up of shorter trees with a highly broken canopy. This difference is explained by the human use of Taula, where harvesting of seabird chicks is a known annual occurrence. There are plenty of signs of cut Puko trees which Watling accredits almost certainly to felling of trees to harvest the birds.

Typical coastal vegetation on Taula

The birds that were observed on Otu Motu Lalo are a combination of migrating species from the north and resident species of Tonga year round. During the two baseline studies, 21 species of birds were identified between the two islands. Of these species, three are resident breeding land birds (Wattled Honeyeater (Foulehaio carunculata; Fuleheu), the Banded Rail (Gallirallus philippensis; Veka) and the Collared Kingfisher (Todiramphus chloris; Sikota)), the rest are seabirds. Of the 21 species identified, five of them nest in these identified islands. The greatest abundance of nesting birds are the Black Noddy (Anous minutes; Ngongo)with an estimated 13,000 breeding pairs, next most abundant are the Brown Noddy (Anous stolidus; Ngongo) with an estimated 1500 nests across both islands and then the White Tern (Gygis alba; Tala) with an estimated 1,000 breeding pairs. 

Black Noddy (photo: 10000birds.com)

Brown Noddy (photo: 10000birds.com)

White Tern (photo: Dave Wiley)

 Red-footed Boobys (Sula sula; Ngutulei) also nest on both Maninita and Taula, but are found in higher numbers on Taula. It is thought that, unlike the noddys and terns, the boobys nest all year round and therefore the number of nests (approximately 50) found during the baseline surveys were not representative of the population size. This was further supported by the large number (compared to number of recorded nests) of Red-footed Boobys coming to roost, rather than nest, on both islands each evening or in high winds.

Red-footed Booby & Frigate Bird, Taula

 

Red-footed Booby over Taula

In addition to this, Taula hosts a breeding colony of Black Winged Petrel (Pterodroma nigripennis; Lafu). These birds nest in burrows up to one meter deep that they dig in sandy soil, visiting them late in the evening and at night. While Dr Watlings’ baseline survey was a comprehensive study of all flora and fauna species of the islands, he was unable to quantify the occupancy of the petrel nesting burrows. This is owing to a local village party that had visited the island a week before the survey and ‘devastated the colony’ through harvesting. It was felt by the survey team that additional disturbance of the nests would be detrimental to the health of any surviving birds. Therefore burrow numbers were used as an estimate of colony size and a figure of 200 petrels was derived.

Black Winged Petrel (photo: Nvoaden)

Petrel burrow on Taula (photo: D Watling)

  

The studies conducted by Dr Watling and his team show Maninita and Taula to be very important seabird nesting colonies with intact native flora. BirdLife International’s Important Bird Area proposal document states that these islands are some of the best remaining examples of Tonga’s small island ecosystems. However, the attributes that make them such important ecosystems are under threat from continued human exploitation and the lack of any management framework. 

Remains of a booby at a camp site on Taula

As well as being important nesting islands, the Otu Motu Lalo islands are also important nesting grounds for Vava’u’s marine turtle species and as such will be visited by the Vava’u Turtle Monitoring Program on an annual basis. We will be able to use this time to also monitor the seabird nesting population and human activity on these islands and look for any worrying trends that may emerge. 

 

Busy birds and stormy skies - large flocks of seabirds over the outer islands of Vava'u

 The first turtle surveys were completed during January 2013 and many eggs and chicks were observed on Taula with large flocks of seabirds being visible at all times. Seabird nesting was found on most of the outer islands visits, but without doubt, Maninita and Taula were the busiest. We have since made contact with Dr Watling and will be able to use his baseline data to compare any additional bird data that we collect.

Noddy egg in a nest on Taula

Very young noddy chick on Taula

Black Noddy chick getting close to fledgling on Taula

If you would like to find out more please contact us at info@vavauenvironment.org

Malo, Kate

Exploring Vava'u's Environment

Vava'u Island group comprises of over 40 limestone islands of which only 14 are inhabited. The natural resources of Vava'u are scattered between the marine and terrestrial environments.

Each month we will be writing a blog post on different areas of Vava'u environment to help share in its beauty, we will also be discussing other topics of conservation interest that threaten and potentially effect the environment and the communities who use them.

We would love for people to share with us topics that they would like to hear about so please add comments and share around.

Our first topic which will be for the end of the month is the terrestrial or land environment.

Some of the stunning islands.

Vicky's Experience as a VEPA Volunteer

Loved it. It was an amazing experience I will never forget. Where to start? ... VEPA, it is an honour to have been part (even a tiny little part) of this organization, its strong, honest, devoted dedication to the community, giving back to the community asking nothing in return other than cooperation... every time I’ve had to mention I was a VEPA volunteer, I said it with pride. It is really good that almost every person I’ve mentioned VEPA to, knew what it was. It’s great to see that the organization is growing, and more and more people want to get involved (whether its a little bit or a lot).

And this wouldn’t be possible without the amazing work of Karen Stone and Elana Balderstone. Of course the rest of the board members, volunteers, and friends of VEPA are all part of the success of VEPA, but I will speak of Karen and Elana because I worked with them the closest. Two amazingly hardworking women that breathe and sweat VEPA.

I keep saying to everyone I’m the luckiest person in the world for having been assigned the Matamaka Coral Nursery Project. It involved everything I enjoy... field work, kids, culture, beautiful scenery... I’m not very good with paperwork and computers, and even though I mentioned I would have like to help more around the office, I am very glad I was out doing hands-on work most of the time, and in a stunning place like Matamaka, who would complain?! I love swimming, I love the ocean... having it as my ‘office’, I enjoyed the early wake-ups. The most rewarding part was probably being involved with kids. They are so much fun, always excited to go swimming and for me to show them the reef. My first week there, I was teaching them how to use the snorkels and fins. They picked it up pretty fast. Sometimes there were a few problems with water getting in the mask. After that it was always “Vicky, are you going Swimming? Can I come with you?” and that way, every week I’d take a few kids out. 

I think they didn’t even know they had that reef there or what a reef looked like until they saw it through the masks. The moment we started approaching the first corals (and seeing the first fish), they would not stop pointing at anything and everything!  I would tell them the family names of the fishes but it was all too confusing in the water with so many fish around us. We did a little activity in class where they had to colour some black and white fish and match them to some photos of the common fish I had seen in Matamaka. They loved that and they were all very artistic. Having spent almost as much time in Matamaka as in Neiafu, I truly got to experience the Tongan culture. At first, the adults in the village were a bit confused about who I was and what I was doing there but little by little I got to know a few of them, and they got to know me, and then it became a normal thing having me walking around the village. I travelled on the little fishing boats every time to and from Matamaka, ate Tongan food (and Tongan portions), ‘showered’ with a bucket of water, went to church a few times, served kava, went camping, danced, sang, and laughed a lot.

Building the coral nurseries was fun, I’d walk around the village looking for the materials, take them to my little office (the tree by the jetty), putting the ropes and the frames together, placing them in the water...   starting to get the feeling that everything was finally coming together. Then, finding the right coral fragments and attaching them to the frame, that’s when it started getting a bit more complicated and cold (spending maybe 2 hours in the water until I could no longer feel my fingers). Collecting the corals was not as easy as I thought at first. 

Yes, there were a lot of fragments on the seabed, but as the beach in Matamaka does not get any wave action, fragments found there have been broken off by past cyclones. Who knows how long these fragments have been lying there, most of them have some algae growing on them. I’d dive to collect a fragment, which looked good from the surface and then turned out that the bottom was covered in algae. I ended having to replace many fragments week after week.

Another little complication was finding the perfect location to place the coral frame. Corals need clean water, with low nutrients and no suspended sediments. The first location chosen was not good, so much sediment everywhere...after a week when I went to check on them, all the fragments were bleached and covered by the sediments. I then decided to move it to the other side of the jetty where there is plenty of coral and a lot more fish. This turned out to be a much better location as most of the fragments kept their colour when I checked up on them week after week. Since we had a spare frame thanks to IMAX donating the materials, the second one was placed on the right side of the jetty but away from the rocks and all the sediments. It is a bit deeper but it’s on a sandy area and was placed next to a bommie with at least 5 different species of corals growing on it. We’ll have to see if the depth at which the frames were placed has any effect. Hopefully the coral will grow well on both frames! I’d love to come back next year (or in a few years) and see the small fragments turned into big colonies!

Hopefully the kids will stay motivated and continue the monitoring to the point where they see some growth and understand the benefits of the reef. Nevertheless, I do believe the kids learnt something, even just a little bit about how important the reef is and that it is crucial to look after it.

My experience as a volunteer for VEPA was truly amazing. I am really looking forward to coming back to Vava’u and of course being involved with VEPA again! Thanks so much to everyone in VEPA for giving me this wonderful experience.

Ofa 'atu, Vicky von Bernard, International Volunteer