Eastern Rosella

This beautiful Eastern Rosella specimen was spotted in a small woodlot adjacent to a park created by the Waitakere City Council (Waitakere City is incorporated in the Auckland Metropolitan Area). This rosella is native to southeast of the Australian continent and to Tasmania. It has been introduced to New Zealand where feral populations are found in the North Island.

This rosella has a red head and white cheeks. The beak is white and the irises are brown. The upper breast is red and the lower breast is yellow fading to pale green over the abdomen. The feathers of the back and shoulders are black, and have yellowish or greenish margins giving rise to a scalloped appearance that varies slightly between the subspecies and the sexes. The wings and lateral tail feathers are bluish while the tail is a dark green. The legs are grey. The female is similar to the male though duller in colouration and has an underwing stripe, which is not present in the adult male.

The Eastern Rosella is found in lightly wooded country. It eats grass seeds and fruits. Breeding occurs in spring and early summer and up to seven white eggs are laid in tree hollows.

The Eastern Rosella is sometimes kept as a pet. These birds are coveted for their beautifully coloured plumage. They are quite intelligent and can be trained to whistle a wide repertoire of tunes and may even learn to speak a few words or phrases.

Rosellas can make good companion pets; however, they require a great deal of attention and many toys to satisfy their need for social interaction and mental stimulation.

Australian Water Dragon at Auckland Zoo

Juvenile Australian Water Dragon

Photographed this fine specimen of a juvenile Australian Water Dragon, Physignathus lesueurii basking in the sun at the Reptile House in Auckland Zoo. Australian Water dragons are arboreal agamid lizards native to Eastern Australia from Victoria north to Queensland.

I was particularly impressed by its beautifully patterned scales and black and white colouration. Water dragons have long powerful limbs and claws that are well adapted for climbing and a long muscular laterally-compressed tail to aid swimming.

Adults, especially, males have prominent nuchal and vertebral crests. The nuchal crest is a central row of spikes at the base of the head. These spikes continue down the spine, getting smaller as they reach the base of the tail.

Adults prefers habitats near water and are often found in trees overhanging water from which they will drop into the water if disturbed, enabling them to escape. Juveniles prefer low vegetation near water.

Water Dragons reproduce by laying 6 to 18 eggs. The female Water Dragons dig shallow nests in a sunny open position generally in sandy soil. The nests are normally located not far from water, either near rivers, streams or ponds.

Water dragons exhibit a very interesting phenomenon called Temperature Dependent Sex Determinaton. Sex of the hatchlings is related not to sex chromosomes but to the prevailing nest temperature. Females are predominantly produced at hot and cold temperatures (above 28 degrees Celsius or below 26 degrees Celsius) and males at intermediate temperatures (26 to 28 degrees Celsius).

A visit to the Gannet colony in Muriwai, New Zealand

Australasian Gannet, Morus serrator

I was fortunate enough to once again visit the gannet colony in Muriwai in January, 2010. The last time I had visited the Muriwai gannet colony was in 1999 en route to Melbourne to participate in the 1999 World Scrabble Championship Tournament. From Auckland, Muriwai beach is about an hour’s driving distance. My brother Sunil’s in-laws live very close to Muriwai and after an early lunch we proceeded to Muriwai.

One of the vertical-sided islands with nesting gannets

A short walking track from the car park leads to a viewing platform right above the main colony area. Out to sea, the colony continues on two vertical-sided islands. Nothing much had changed since my last visit to Muriwai, except that I had a better camera. One was magically transported to another world which effectively shut out the ordinary mundane world. The gannet nests are just centimetres apart. The whole surreal scene looks like an air traffic controller’s nightmare, but somehow these graceful birds have it under control. Those coming in to land must glide over the squawking raised beaks of their neighbours.

With its 2-metre wingspan, golden head and dramatic plunging dives, the white Australasian gannet is an easily identified seabird. Gannets and boobies belong to the family Sulidae. Adult gannets are about the size of a goose, with black-tipped wings, black central tail feathers and a strong, conical blue-grey beak. About 1200 pairs of gannets nest here from August to March each year. It is believed that gannets mate for life, and they tend to return to the same nest site each year. Each pair lays one egg and the parents take turns on the nest.

Courting gannets

Gannets hunt fish by diving from a height into the sea and pursuing their prey underwater. Gannets have a number of adaptations which enable them to do this: they have no external nostrils; they have air sacs in their face and chest under their skin which provide cushioning just like airbags in a car; their eyes are positioned far enough forward on their face to give them binocular vision, allowing them to judge distances accurately.

Nesting gannet

Gannets can dive from a height of 30 m, achieving speeds of 100 km/h as they strike the water, enabling them to catch fish much deeper than most airborne birds. You can spend hours watching these powerful birds dive headlong into the roiling waves and emerge a few moments later with fish struggling in their beaks while they serenely bob on the ocean surface. They are such expert fishers that I rarely saw a bird come up without any catch.

The gannet’s supposed capacity for eating large quantities of fish has led to the term “gannet” being used to refer to people that steadily eat vast quantities of food, especially at public functions.

 

An almost fledged gannet chick

Juvenile birds look quite different from the adults. In their first year, they have speckled brown feathers on their upper body, and white undersides. Each year, more white feathers appear on their backs, and the birds acquire their adult appearance by five years of age. A few weeks after hatching, the chicks begin to exercise their wings in preparation for the one-shot jump off the cliff. Once airborne, the young gannets leave the colony and cross the Tasman Sea to Australia. A few years later, surviving birds return to secure a nest site at the colony.

I was also able to spot white-fronted terns on the ledges of the cliffs below the gannet colony. The terns are smaller than gannets, flying rather like large swallows.