Thursday, 10 November 2016

Coral Cay Island Birds – Great Barrier Reef – Part 2 Black Noddies

The background to our recent visit to Lady Musgrave Island on the Great Barrier Reef (GBR) was given in the previous post.

There were thousands of Black Noddies breeding on Lady Musgrave Island.  However long before reaching there we crossed paths with Black Noddies out at sea as they moved about hunting for food.

Noddies are terns. Three species are found in Australian waters, the Black Noddy (Anous minutus), Common Noddy (Anous stolidus) and the much less common Lesser Noddy (Anous tenuirostris) which appears to be restricted to the Indian Ocean with some birds found off the Western Australian coast.

Click on images to enlarge.

Black Noddy perched in a Pisonia tree on Lady Musgrave Island.
Black Noddies take small fish, plankton and jellyfish from the surface of the sea and while we passed many birds flying alone out at sea, the feeding events we saw involved small to large flocks of birds (I am not implying here that individual birds do not forage alone).

Part of a Black Noddy flock feeding at sea. There are over 100 birds in this image which has captured about half the flock.
At times the feeding seemed frenzied and in places it looked like a chaotic melee.

Black Noddies are sedentary and do not migrate after breeding. Their breeding is “aseasonal” (without season, that is no rigid breeding schedule) with an increased likelihood of breeding events in spring and autumn. They are colonial breeders and may have one or to broods per year. They build substantial nests of leaves and seaweed, cemented together with faeces, in trees and small shrubs and occasionally they nest on the ground. Only one egg is laid per brood. Both sexes share incubation and the care of young.

Given there is no rigid breeding schedule, we were very fortunate to visit Lady Musgrave Island when a large Black Noddy breeding event was underway. Thousands of nests were either finished with birds sitting on eggs or still under construction as we saw many birds gathering leaves and seaweed. Most of the nests were located in the Pisonia trees however Pandanus Palms and Tournefortia trees (see previous post) were also being used. There were dozens of nests in each tree.

Black Noddy on a nest of leaves and other material, held together with faeces.

The price of nesting colonially and using faeces to cement nest materials is a good amount whitewash on feathers at times. I guess the next trip to sea to feed will wash off the mess!

This piece of seaweed proved to be far too large and heavy to be lifted and carried to the nest.

A piece of grass floating near the shoreline was of great interest to a number of Noddies still gathering nest material.

I watched many attempts to pick up the grass, often with two or more birds competing.

This bird managed to lift the grass a short distance above the water but eventually had to drop it as it was far too heavy.

I found small groups of Noddies, between 5 and 20 birds at times, on the beach sand picking up and swallowing grit. At first I speculated that this was used to somehow help digestion, however given the grit was calcareous (pulverised coral and shells) perhaps it was to aid egg shell production, in which case they would have been female birds! Small groups of Noddies also gathered on the beach to sun themselves, often with an outstretched wing, this may have been a way of removing parasites?

Noddy on the beach picking up shell grit.

Photographing the Noddies in flight at sea from a moving boat proved to be a great challenge partly because they are small fast moving birds but also because their dark soft sooty plumage makes autofocus difficult even under static conditions. In addition, on the beach the tropical light was very harsh. Also the birds have predominantly near black/dark brown plumage with a maximum contrast silver/white cap which makes exposure difficult. Either the body is well exposed - in which case the white cap is overexposed, or in the reverse case  - the cap looks good but the body is rendered completely black. However, I eventually managed to capture some acceptably exposed and in focus images of Black Noddies in flight.

Black Noddy in flight.

Bird with another leaf to add to the nest.
Each tail feather ends with a point.

I think I may have become a little obsessed with the challenge of capturing Black Noddy photos?

It is hard to estimate how many breeding Black Noddy pairs were on Lady Musgrave Island but the number was easily in the thousands. It was relatively quiet while we were there with birds finishing nests or sitting on eggs. Once the young hatch I imagine the Pisonia jungle would be a very busy, noisy and smelly place.

Regarding the genus names for Noddies, both scientific and common, Anous and Noddy respectively, Fraser and Gray, “Australian Bird Names” provide the following explanations:

Anous ”stupid bird”, from Greek anous, foolish (having no nous, in fact).
Noddy  “is and old English word meaning simpleton. It is presumed that insult was directed at the bird for being trusting of marauding sailors in its breeding colonies.”

Clearly Noddies evolved to breed colonially on remote offshore islands free from human and other mainland predators. In addition, the birds are pelagic, spending their lives at sea and rarely visiting mainland beaches so they did not come into contact with people over the thousands of years of their evolution. It was not until relatively recently that these birds encountered European sailors in their breeding colonies. Today the names do appear to be insulting for a beautiful trusting bird that has simply evolved that way. The names are certainly an historic reflection of the minds and world view that existed in the early days of European exploration and colonialism.

We found the Black Noddies just as trusting today – they tolerate very close approach to their nests which is a very special experience – thousands of years of evolution does not change in a few short years.

In the next post (Part 3) I will cover other Tern species found on Lady Musgrave Island.

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