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.