Lord Howe Island birds

Two Lord Howe Island Pied Currawongs on the summit of Mt Gower

Oceanic islands, far from large landmasses, often have a suite of unique fauna, and as Lord Howe Island is quite isolated, it has such a list. Unfortunately, as with many islands, some of the native species have been lost, a euphemism for having been eaten to extinction by man or animals introduced by man. Nevertheless, it still has the character of a wild island, especially up on Mount Gower (see previous post) and here are a few birds which added to my recent experience there.

The local subspecies of Pied Currawong has a longer, narrower bill than the nominate race.

As we climbed up through the forest to the plateau, loud chuckles and coughs followed us from the thick canopy. These were the calls of the local Pied Currawongs Strepera graculina crissalis, which have a distinct island accent, and they seemed to be telling one another of our approach.

A little more secretive, but never timid, and quite happy to forage around our feet as we passed, were the Woodhens Gallirallus sylvestris, This flightless species was saved from extinction, by the collection of a group of birds which had escaped predation on the almost inaccessible summit plateau, screened off from pigs etc by cliffs. The birds bred successfully in captivity and now that birds are running wild in the lower forest as well as the plateau, the future looks bright for the species.

 Lord Howe Island Woodhens forage for food in the rich basalt and leaf-litter soils 

Meanwhile all around, there is the incessant calling of Providence Petrels Pterodroma solandri in the sky.

Providence Petrels wheel around the Mt Gower cliffs

Ocean, cliffs, high hilltop, mist forest and flocks of petrels - a wonderful experience

There aren't many viewpoints out from the plateau as the forest is so dense, but looking out over the ocean from so high added an extra quality to the scene. Then our guide, Dean, called some petrels down. All he did was give a few yodels and in they came, crashing through the canopy and onto the ground.

Some petrels landed clumsily on branches

Others crashed to the ground and immediately started to squabble

They had no fear of us whatsoever

Unfortunately for the species, due to their disregard for humans, Providence petrels were eaten to extinction on neighbouring Norfolk Island. They were so easy to kill. There were more people on that island than Lord Howe, as there still is today, and it is probably lucky for the birds that Lord Howe has never been highly populated by man. Although who knows what hidden anthropogenic dangers might still wipe them out - they eat plastic debris in mistake for food, it accumulates and fills their stomachs, eventually causing death by starvation. Let's hope this doesn't lead to another extinction.

To see a clip of David Attenborough calling down Providence Petrels on Lord Howe Island click here

Mist Forest

Mount Gower (on the right) is often kissed by cloud on even bright sunny days

On a recent trip to Lord Howe Island, I went up onto the summit plateau of Mount Gower to see the lush growth of plants there - mist forest plants, growing on a sub-tropical island far out in the ocean.

The cloud which gathers on the summits of Mounts Lidgbird and Gower
 adds height to the perspective when seen from the fields

The twin peaks of Mounts Lidgbird and Gower stand tall over the rest of Lord Howe Island and to me, with my sense of exploration, I just had to go up there, to Mt Gower, the higher of the two at 875m.

The mist brings water to what might otherwise be a very dry place

There is no easy way up there, as the rise is so steep and cliffs block most lines of approach.

The first part of the climb follows the path across this cliff at mid-height,
then around the corner and up a steep valley to the final tower

On the plateau, the vegetation is short, wind-clipped as on most mountains, but still several metres high. Although oceanic, it is so high that there is very little salt in the atmosphere. The whole gives the effect of a ground covering of ferns and shrubs, linked to a low canopy by a tangle of moss-draped branches.

The rich vegetation crowds over the faint path

Overall, the colour is green vivid, leafy green - with the calming effect of a studio green room. And it is dark under the lush spread of palm and fern fronds - difficult conditions for photography.

It is a true jungle up there

Showy plants like the orchids catch most people's attention, but once seen there are other botanical treasures.

Bush Orchid Dendrobium macropus howeanum

Little Mountain Palm Lepdorrhachis mooreana
one of several endemic species only found on the top of these island mountains.

It is the abundance of lush growth that is the overall impression, especially that of the mosses which swarm over branches, stumps and rocks. It is their presence that tells this is a true mist forest, for they could not live without the frequent covering of cloud on those ocean mountain tops. 

Moss in so many forms like this feathery species

A moss blanket spread over a boulder

And a meandering trail of moss climbing over all on its way

New paper on Tawny Frogmouth nesting behaviour

The cover of the current edition of Australian Journal of Zoology is illustrated with one of my photographs,
showing a Tawny Frogmouth in a typical nest site

The current issue of the Australian Journal of Zoology carries a paper by me and Duncan Rae on the nesting behaviour of Tawny Frogmouths in the Canberra area. This presents and discusses a set of results based on 253 nest records over several years. The brief online abstract and citation are reproduced below, but the full abstract and paper can be obtained by clicking on this link: Orientation of tawny frogmouth (Podargus strigoides) nests and their position on branches optimises thermoregulation and cryptic concealment

Tawny frogmouths (Podargus strigoides) in south-east Australia place their nests on open coarse-barked branches orientated to the north-east. This would fit their cryptic plumage and behaviour, expose the nesting birds to sunshine, shelter them from prevailing wind, give good visibility for detecting predators and clear space for rapid escape.

Rae, Stuart and Rae, Duncan (2014). Orientation of tawny frogmouth (Podargus strigoides) nests and their position on branches optimises thermoregulation and cryptic concealment. Australian Journal of Zoology 61, 469-474.

A Tawny Frogmouth sits over his two chicks

Striated Pardalotes - juveniles

A juvenile Striated Pardalote - nominate Pardalotus striatus striatus

When we caught two young Striated Pardalotes Pardalotus striatus on the last trip to Charcoal Tank (see previous posts), I noticed that they were of different subspecies. The one above is of the nominate type striatus, which only breeds in Tasmania and spends autumn and winter on mainland Australia, where it overlaps the range of two subspecies, ornatus and substriatus. The nominate has yellow wing-spots, colouring on the tips of the greater primary coverts, while the subspecies have red wing-spots - see below.

The yellow wing-spot on the primary coverts of a  Pardalotus striatus striatus

The red wing-spot  on the primary coverts of a Pardalotus striatus substriatus
(The wide band of white on primaries differentiates this subspecies from the similar subspecies ornatus, which has narrow white edges to the primaries. See post of  17th September 2012)

A juvenile Pardalotus striatus substriatus

Then I noticed that the striatus juvenile's moult into adult type plumage was less advanced than that of the substriatus bird. In particular, its crown was still spotted rather than streaked like that of the substriatus (see below). This is only a sample of one from each subspecies, but I wonder whether the young Tasmanian striatus birds deliberately delay their moult until they have migrated across the Bass strait and settled in their winter range on the mainland. Meanwhile the resident subspecies of South-west New South wales, substriatus, begin their moult as soon as possible. Both birds were caught on the 15th March 2014. If the Tasmanian birds migrate from March-April (HANZAB), this bird would have been one of the earlier to leave. Would it have been one of the earlier to hatch too? If so the delay in its moult would be more likely a strategy to moult post migration. I would be grateful if anyone has more information on the plumages or migration strategy of juvenile Tasmanian Pardalotus striatus striatus.

Juvenile Pardalotus striatus striatus,
with a spotted crown

Juvenile Pardalotus striatus substriatus,
with a partially streaked crown

                               

Australian Emperor Dragonfly

While out at Charcoal Tank Nature Reserve, by West Wyalong, NSW last weekend, where we were catching birds as mentioned in the previous post, Tony Stokes found and pointed out a dragonfly which was perched on the trunk of a Red Ironbark while the sky was overcast and dull.

This was an adult male, identifiable as such by the pair of claspers on the end of the abdomen.

It was an Australian Emperor Dragonfly Hemianax papuensis, which is common and widespread throughout Australia, New Zealand, New Guinea and neighbouring islands. It is a large insect, about 7 cm long, with a predominantly yellow head, thorax and abdomen, striped with contrasting brown or black. The choice of a dark-barked tree for a roosting site showed off the yellow well, especially on the leading edges of its wings. While the dull sky and cool air kept it motionless, giving a chance to see the detail of the insect's intricate wing-vein structure.

Seen from an angle, the insect's aerodynamic form is perfect 

Young birds - how to determine their age

A young Striated Pardalote, less than one year old

On the last trip to study birds at Charcoal Tank Nature Reserve, NSW, over the weekend of 15-16th March, which was run by Mark Clayton as usual, we caught a variety of young birds. This was not surprising as it was only a month or so after the main breeding period for most birds in the area had ended, but we caught 26 species amongst the 119 birds caught altogether, and determining the age of birds can be tricky. So to help illustrate just how these young birds were identified, I have set out below some examples of the various methods that can be used to establish their age.

A front-on view of the same young pardalote

Immature Plumage -  The main, quickly seen features which were followed to determine this Striated Pardalote Pardalotus striatus as a young bird were the beginnings of only a few streaks on the crown and no white eyebrow behind the yellow flash above the eye. This bird will gradually moult out its first young-bird feathers and grow true adult-coloured feathers during its first year of life, with a fully streaked crwon and a wide white eyebrow.

A young Double-barred Finch

Feather development - To the trained eye, this Double-barred Finch Taeniopygia bichenovii is likely a young bird as it has narrower black bands across its breast than an adult would have. But that is a relative criterion, which is not of much use if there is not an adult to compare it with. More precisely, it can be aged as a young bird, less than one year old, by the incomplete covering of underwing feathers. In the second image, the flesh and line of the bones can be clearly seen because they are not fully covered like those in an adult bird. The most important feathers for a young  bird to grow are its body feathers for warmth, then flight feathers for mobility. The sooner they can leave the nest, the easier it is for them to escape from predators. So they gradually complete their body plumage in the less exposed parts, such as under their wings, as they continue to develop into full-grown birds. 

The partially bare underwing of the same young Double-barred Finch

A young White-plumed Honeyeater - in its first year

Pigmentation - this can be costly for a young bird to lay down, nothing comes without cost, even in nature. So young White-plumed Honeyeaters Lichenostomus penicillatus concentrate their nutritional resources in growing a basic bill, enough to serve the purpose of feeding, preening etc.. There is no need for deep pigmentation. That is added slowly during its first year of life, and by the following breeding season it will have a fully black shiny bill, a sign of an adult bird in breeding plumage.

This first-year White-plumed Honeyeater is probably a few months old and has begun to grow a dark bill,
 starting from the tip

Young Sacred Kingfisher - less than one year old

Buff-tips - many young birds have buff-tips to some of their feathers, such as this young Sacred Kingfisher Todiramphus sanctus, which has such feathers in its wing coverts and crown. Most of these will be moulted out during the first year, and the bird will be in adult breeding plumage in time for the next season. Some other species can retain a small number of these buff-tipped feathers into their second year while they are breeding, but if a Sacred Kingfisher has lots of such feathers between breeding seasons, then it can be confidently classified as a first-year bird. 

A back-view of the same kingfisher - this bird has a broken tail feather, snapped along the line of a fault-bar. This is a weak part of the bird's tail feather which is a result of less keratin being laid down in the feather during a period of less nutrition intake as the young bird's tail grew

A young rainbow Bee-eater

Ornamental feathers - or lack of.  Some species of birds grow elaborate ornamental feathers as part of their adult breeding plumage, like the Rainbow Bee-eater Merops ornatus which have extended central tail-feather streamers. The young birds however, do not grow these. To grow such feathers for no purpose in their first year, as they are only required for breeding display, would be an excessive waste of nutrition. 

Gang-gang Cockatoo Survey

An adult male gang-gang inspects a potential nest hollow

Today saw the launch of the Canberra Ornithologists Group's Gang-gang Cockatoo survey. The survey organiser, Chris Davey introduced the project to a group of birders at Corroboree Park, then naturalist Ian Fraser added a few details and anecdotes to inspire people to go out, find the birds and log their results in the online survey - http://canberrabirds.org.au/observing-birds/gang-gang-survey/. All records of Gang-gangs in the ACT and surrounding district are welcome, including negative ones, and there are already hundreds entered. The project runs for eighteen months to cover all seasons fully and we hope to have a clearer picture of where the birds breed, overwinter, and what habitats need to be preserved if the birds are to be here in the future. So if any one in the area can add information to the survey please do, it's easy, and rewarding. 

I was involved in the design and production of the survey brochure, a fold-out introduction to the bird and project. See below.

Huge deposits of pumice on the beaches

Piles of pebbles of pumice lie on the tide-line along the new South wales south coast

The sandy beaches and hidden coves of the New South Wales south coast are presently littered with pumice pebbles. They have come from 4000 km out in the Pacific Ocean, north of New Zealand, where a submarine volcano on the Havre Seamount, near the Kermadec Islands erupted last July. This caused a raft of pumice covering 20,000 sq km to form and gradually drift west on the currents. When they reached the Australian coast they were washed up and concentrated on the tide-line. 

The pumice formed as lava erupted under water and air trapped in tiny pockets in the rock makes the it buoyant. This was the largest such eruption in the region for over fifty years. There were all sorts of plant and animal life attached to some of the larger and rougher pieces, and I wonder what land-based life will find a niche in the new rocky tide-line. 

The pumice is light and floats like the bladders of the seaweeds which it lies with on the shore

Most of the pebbles are small, but some are as large or larger than a cricket ball

The pumice floated from north of new Zealand to the south east coast of Australia

A few art lessons from Melbourne

Add your name if this is your work, I don't want the credit, just spread the word
Street art on Hosier Lane 14th February 2014

It has been a hot few weeks in Melbourne and I was down to look around some Tawny Frogmouth sites with Marian Weaving who is studying them there, out in suburbia. Then once I did that I went into town to look up the recent artwork. The collections in the galleries were as good as ever, but there were great environmental messages going on out on the streets, especially in and around Federation Square.

In the middle of the square is a triptych sculpture of Dogman and Rabbitgirl riding a rhino, the creations of artists Gillie and Marc. I am familiar with their work, and it is good to see this plea to help save rhinos in such a high profile.

Rabbitgirl and Dogman ride a rhino for life

Thousands of people pass through the square every week, day? Many took photos of themselves in front of the sculpture, but unfortunately very few took the time to read the message. I know, I watched them. Most were tourists from around the world; what apathy from people who profess to enjoy the planet.

Thanks for the message Gillie and Marc

Impressive art for an impressive animal

Meanwhile over on the pavement across from Flinders Street Station, Chris Jordan had built a sculpture of a mobile phone with old mobile phones about to be re-cycled. He was in town to add his voice and skills to the Sustainable Living Festival, to see more on that click this.

A mobile phone made with mobile phones

Re-cycle your old phones!

Chris was giving a talk in the Deakin Edge theatre on various topics concerning our waste and the damage we cause to other animals on the planet. Part of his presentation included a viewing of his powerful video on the effect plastic is having on albatrosses  This was uploaded on line two years ago now, but the message is still the same. If you haven't seen this and would like to watch it, click here, but be warned it is sad, very sad.

More on aging and sexing Rufous Whistlers

Following some interesting feedback on the previous piece on aging and sexing Rufous Whistlers Pachycephala rufiventris, I have added a few more examples of details to look for when doing so.

Adult female Rufous Whistler
Charcoal Tank, NSW, Oct 2010

This first adult female (3+) shows the features of a dark red eye, dark black bill, white throat streaked with dark grey and streaked breast.

Left - Adult female, right Immature (unsexed)
Charcoal tank, NSW, Oct 2010

The shot above shows a second adult female (3+) alongside an immature, unsexed bird (2). Her eye is clearly red compared with the young bird's brown eyes. Her head is grey streaked with black, her belly is pale buff, almost white, and she has very little streaking on her undertail coverts. In comparison, the young bird has a grey/buff head with finer black streaks, its belly is a creamy orange and there is definite streaking on the undertail coverts. The immature bird would have hatched in the Spring two years previous to that when the shot was taken, but as it was still early in the breeding season when the bird was caught, October, and as sub-adult males can breed in their second year while in such a plumage, the bird cannot be sexed. It might yet moult into sub-adult male plumage later in or after the breeding period.

The photograph below shows the heads in profile of the same two birds. Note the female's grey head versus the young bird's brownish colour. Her iris is red, the other bird's is brown. Her bill is black on the outside upper and lower mandibles, and inside. The young bird's bill is dark, almost black on the upper mandible, brownish grey on the lower, and with a pale yellow inside the roof. Also her bill is worn with use, with chips and flecks taken out of it, while the young bird's bill is smooth edged and clean-looking with pale margins.

Left - Adult female, right Immature (unsexed)
Charcoal Tank, Oct 2010

In comparison of the two adult birds, the second adult female has a brighter shade of red in her eye, her breast is less rufous, her belly is paler, and her undertail coverts are less streaked. This might simply be normal variation in colouring between individual birds. However, she might be an older bird, so further study needs to be done on the features listed here on re trapped birds of known age, to help clarify this point.