Chatham Is Black Robin

A couple of our group (Annette & Nikki)are back from the Chatham Islands, where they were helping with the Black Robin post-breeding census. The following post is from Annette.

Departure was delayed several days while waiting for Cyclone Pam to pass over the islands and the sea to calm down. On arrival they found that there was little damage on Mangere Island, which had been largely protected from the full force of the wind and the seas by Pitt Island, but Rangatira had suffered significantly. Many huge old Chatham Island Ake Ake (Olearia traversii) had been blown over, and in some places this had set off a domino reaction, cutting a swathe of destruction through the bush. 

The destruction around the coast was equally dramatic, with immense carpets of muehlenbeckia  rolled up on the rock platforms or torn away completely, and huge straps of bull kelp wound around trees tens of metres above the normal sea level.

Not surprisingly, Shore Plover numbers were down by about 20%.

Male Shore Plover

The Robins had obviously been affected also as they were more warier and secretive than usual, and even reluctant to come down and eat mealworms. 259 adults were present at the start of the breeding season but only 222 of these were seen during this trip. Juvenile numbers were even further down, with 49 seen compared with the 75-80 seen the last two years at this time. However the extent of the losses will not be known until the start of the next breeding season, as the birds may still have been ‘spooked’ and reluctant to show themselves; and on the other hand the combined stress of a summer drought followed by the cyclone may cause higher than usual mortality over winter.

Male Chatham Is Black Robin

 Surprisingly, the smaller forest birds were plentiful. There were many Silvereyes, and more Fantails than I have ever seen, with groups of five to seven frequently present. Warblers flitted around busily and Tomtits were always ready to profit from the robins’ reluctance to eat the mealworms.

Chatham Is Warbler

Male Chatham Is Tomtit

Female Chatham Is Tomtit with mealworm

One positive effect of the storm was that most of the canopy was defoliated and so it was much lighter in the bush. This made it much easier to read the colour bands, and also it seemed warmer as the sun was able to reach the forest floor.

The contorted shapes of the trees show that the island has weathered such storms in the past and doubtless will face more in the future.

Black Robins and other Chatham Is birds

Two of our group, Annette and Nikki have just come back from 3 weeks on Rangatira Island, a Nature Reserve in the Chatham Islands. The main purpose of the trip was to monitor the breeding burrows of endemic Chatham petrels for invasion by broadbill prions and to do a complete census of the Black Robin population and colour band all the juveniles.

They identified 229 adult and 70 juvenile robins. An additional 45 adults and 10 juveniles were seen on Mangere Island, bringing the total post-breeding Black Robin population to at least 354.  Two additional birds managed to elude capture and remained unbanded and are probably the only unbanded Black Robins in the world. For more info see www.chathams.co.nz

 This year they used drop traps to capture the Robins instead of the more usual clap traps. A set of five traps were custom-made by an Upper Hutt engineering firm to fit one inside the other for easy transportation to and from the island.  Despite working well, the traps proved a little cumbersome to carry around in the dense bush and muehlenbeckia on Rangatira, prompting much discussion about the possibility of developing a collapsible version!

Two of the team putting finishing touches to traps Photo Nikki McArthur

 Triggering of the trap is carefully timed for the moment when the robin is facing the back of the trap and lunging forward for a mealworm, as this virtually eliminates the risk of the bird escaping the trap or being struck by the frame as it drops.

Blissfull ignorance – a juvenile black robin thinks about taking the last crucial step towards the back of the drop trap. Photo Nikki McArthur

  On returning to Chatham Island from Rangatira, the Black Robin team took the opportunity to visit the Chatham Albatross translocation site near Taiko Camp on the edge of the Tuku Nature Reserve.  The Taiko Trust has translocated 50 Chatham Albatross chicks from their only breeding colony on the Pyramid to a site on the SW coast of Chatham Island.  Taiko Trust staff and volunteers have been feeding and monitoring the chicks daily for the past three months, and by the day of their visit the 46 remaining birds (4 had already fledged) were on the verge of taking their first flight.  They all felt extremely privileged to have had the chance to visit the site of NZ’s first albatross translocation and only the second such translocation to be attempted anywhere in the world.

Juvenile Chatham albatross standing on its artificial nest and exercising its wing muscles. Photo Nikki McArthur

Blog for Chatham Albatross translocation is https://www.facebook.com/chathamtaikotrust

Chatham Island - Black Robins

Two of our group (Annette & Nikki) have just returned from the Chatham Islands where they were helping Tansy (who did some training with us recently) with the black robin post-breeding census and banding of this year’s juveniles. Almost, (there is at least 1 that is not), all Black Robins are colour banded with individual combos that include a year colour.

Black Robin sporting it's team colours

Most of the Robins are caught in Clap Traps baited with mealworms which are irresistible to most of them, but they are also very tempting for the local Chatham Is Tomtits.

Black Robin in the "Catch Zone" Sorry the pic is on it's side , I can't seem to correct  it.

Chatham Is Tomtit with it's free meal.

Fifty Five robins were found on Mangere Island – 45 banded adults and 10 juveniles that were caught and banded.

The "Robin Bush" on Mangere Is is a very small patch of green on a big rock called an Island.

The bush area is much larger on Rangatira Island, and 195 adults and 91 juveniles were found. 100 of these were unbanded. They caught and banded 99, but despite much attention could not get number 100 which was not interested in mealworms, and she remains unbanded.

There might be a few more birds on Rangatira that managed to avoid them on this trip. As these are the only two places where Black Robins are found the total world population in April 2013 is about 341: at least 240 adults and 101 juveniles. All these are descendants of just a handful of birds including just the one female, Old Blue who saved the species from extinction. 

The oldest bird found on the trip was a female G/A-G/G that was banded in 2005, unfortunately last year's oldest bird, which was 13 years old, fledged last century and was banded by the late Don Merton was not seen this year and is presumed not to have survived.