Mystery Bird

Ken Bissett's photograph of the mystery bird posted on the chatline

There was a recent request for help with the identification of the above mystery bird in the local Canberra Ornithologists' Group chatline (http://canberrabirds.org.au/). The query was by Ken Bissett of a small bird he had seen at Mulligan's Flat Nature Reserve, an area of woodland north of Canberra. The first online suggestion was that it might be a juvenile Brown-headed Honeyeater Melithreptus brevirostris, and another was a juvenile Western Gerygone Gerygone fusca. It is now early autumn and there are many young birds about, with confusing plumages. The latter is correct and I present below a selection of images to help explain the reasoning for this conclusion.

A first-year Brown-headed Honeyeater

Both species are woodland birds with light greenish/grey upper-parts and pale under-parts, and they are similar in size, about 100 mm in total length. However these are relative colour comparisons which can vary between individuals at different times of the year, so it is better to refer to specific features.

The same Brown-headed Honeyeater in profile

Ken's bird has a pale grey crown and dark grey legs and feet whereas a young, first year Brown-headed Honeyeater has a pale brown crown as pointed out by Mark Clayton, and pale yellow legs and feet, as pointed out by Richard Allen, in replies to the query. This Brown-headed honeyeater also shows a faint buff/yellow line across the nape.

An adult Brown-headed Honeyeater

For comparison between young and adult Brown-headed Honeyeaters, note the dark bill in the adult and the dark greyish-brown crown and side of head, with a clear white line across the nape.

A first-year Western Gerygone

A young, first-year Western Gerygone has a grey crown with no line across the nape (there is no such line on Ken's bird). It has a white eyestripe, emphasised by a dark line between the eye and the base of the bill. This is faint on Ken's bird, but it is there.

The same first-year Western Gerygone seen from the rear

When seen from the rear, the gerygone has obvious white markings on the tips of its tail feathers, which the honeyeater does not have. An alternative, old, name for the gerygone is the White-tailed Warbler, so that is a good feature to look for.

An adult Western Gerygone

There is no ambiguity between the adults of the gerygone and honeyeater. The adult Brown-headed Honeyeater has bold dark head markings and yellow legs and feet. The adult Western Gerygone has no bold head markings, only the small eyestripe. Its main distinguishing features are its red eye, grey legs and feet, and a dark band across its 'white-tail'.

The same adult Western Gerygone seen from the rear

First year plumage

I was out west over last weekend catching birds as part the long-term study at The Charcoal Tank Nature Reserve, which is a cooperative site and the trip was organised by Mark Clayton. The most noticeable trend that I noticed amongst the birds we caught and banded was the high proportion of young birds. It is the end of the breeding season for the passerines and most of the young were free-flying and independent, although some were still being fed by attending parents. The other point I noticed was the different strategies of moult that the various species have adapted to suit their lifestyles. Below are only a few examples.

A first year Sacred Kingfisher Todiramphus sanctus

This young Scared Kingfisher was in perfect condition with a full set of fully-grown flight feathers, all with fine clean edges. This is a single brooded migrant species and the adults had probably flown north already. The buff tips to this bird's crown and covert feathers indicate that it is a bird hatched in the recent breeding season. So, this bird was ready to fly north probably following innate properties to guide it to its winter quarters in the north of Australia or perhaps Papua New guinea.

A first year Yellow-plumed Honeyeater Lichenostomus ornatus

This young Yellow-plumed Honeyeater is clearly very young, as it still has a yellow gape - the flap of skin at the base of its bill. Therefore, this bird was from a late brood, perhaps a second or even a third reared by its parents. Unlike the kingfisher, this is less critical as it will not have to fly far very soon. At most it will probably range locally or nomadically in and around the breeding region. This bird will join a flock of its species, probably a mixed flock of several honeyeater species, unlike the kingfisher which will live singly until it returns to breed.

The same Yellow-plumed Honeyeater - face on

The plumage details which discern this bird as a youngster are: the brown feathers on its back and crown, the incompletely-grown wing coverts, some of which are still in quill, the yellow base to its bill, the pale brown streaks on its throat and breast and the thin yellow line across the side of its neck.

An adult Yellow-plumed Honeyeater - face on

The plumage details which discern this as an adult Yellow-plumed Honeyeater are: the bright yellow crown with no brown feathers, the yellow plume feathers standing out from the sides of its neck, the heavy black streaks on its throat and breast, and the lustrous black bill.

A first-year Restless Flycatcher Myiagra inquieta

The young birds of the two previous species were both similar in plumage pattern to the adults, only less brightly marked. However, this young Restless Flycatcher is different from the adult birds, it has an orange/buff breast, the adults have almost pure white breasts. These flycatchers live singly when not breeding, or at most in pairs if they stay in their local area, but very little is definitely known of their non-breeding movements. They are also multi-brooded, so any young birds from early broods have to share habitat with breeding pairs, and those pairs would not be their parents if they move from their natal area. Therefore, by having a distinctly coloured breast any adult birds can identify them as youngsters and not regard them as a threat to their breeding, So they are less likely to attack the young birds and the immature birds can live unobtrusively with less harassment. This young bird has a fully grown set of fight feathers, but the primaries and their coverts are a dull dark grey, these are shiny black in the adults. Although, shiny black is not a true appraisal of this wonderfully coloured bird's plumage. The dark feathers have a rich metallic blue lustre, and when they raise their crest as in the image below, they present a very vivid frontage. This young bird has not quite grown all the lustrous feathers on its crown, some still have dull tips. But by next year's breeding season, they will be truly magnificent and offset by a bright white breast. A handsome bird indeed.

The same Restless Flycatcher - face on

Too hot sometimes

Meadow Argus Junonia villida

When I came home this morning there was a butterfly sun-basking on the wall next to the front door, which faces east. It had clearly found the wall a perfect place to catch the morning sun for its daily warm-up. However, by the time I returned it was sitting with its wings closed to avoid the ever warmer sunshine.

The shadow cast by the butterfly was so clear

Then, as I walked past the butterfly I noticed how it seemed to be in a rather awkward pose. It was aligned askew with the wall.

A minimal shadow

But as ever, things make sense in nature. The butterfly had aligned itself along the direction of the sunshine, and angle, so that it cast the smallest possible shadow.

It was holding itself perfectly, all in line with the sunshine by leaning and twisting its body

I took a look from its front, and I was impressed by how it held itself stationery, although I expect that it had moved ever so slightly to re-align as the sun rose and arced across the sky.

Very well adapted - the butterfly was even tilting its body to minimise exposure to the sunshine

As for the species, a Meadow Argus, I usually only see them in the nearby forest glades, often feeding on ground cover weeds, and they are usually much to flighty to photograph. I have seen them in the garden over the past few weeks, but this is the first one I've managed to grab a picture of.  This is a freshly emerged example, note its clean complete and un-frayed edges. My butterfly guru, Suzi Bond, tells me there has been a noticeable emergence in recent weeks.

A spider jewel

A female jewel spider Austracantha minax

It's late summer, spider time.

I have been busy at the desk for most of January, hence the shortage of recent posts, but that is all part of my seasonal behaviour. When the sun is out at this time of year in Canberra, it is not much fun walking about in the hot bush, so I use the time to catch up on writing and editing photographs. Meanwhile, as the summer has progressed, the spiders have been more active and I found this little beauty spinning her web this morning, before it was too hot - for me that is not her.

She is a Jewel Spider, otherwise known as a Christmas spider as they are abundant from then on, or another name is spiny spider. I like that last name as it is so apt. They have six spines set around the hind edge of their abdomen. And the jewel name is apt too, as their glossy bodies catch the light, with all those little pin-spots of colour on the abdomen. Most of those are white on the dorsal, top, side and yellowish orange on the ventral, belly side. This spider is hanging upside down as she was walking along her silk threads, and as she has such a heavy abdomen, she was belly up.

They are only about 7-8 mm long and the abdomen is so large in proportion to the rest of her body that the cephalothorax can barely be made out in these photographs. Her legs are also quite long, and in the top image, the two hairy black pedipalps can just be made out at the front, between the legs. This spider was busy spinning a new web, a circular orb-type, suspended between some grasses about a metre tall. It was nice to see a bit of colour, in the dusty sunshine.

Hot summer

A female Cabbage White Pieris rapae feeds on a dandelion flower

It's January, mid-summer in Canberra, and it's hot. So, I have been a little quiet recently, keeping cool and getting back into working at the desk. I try to take short sorties into the local bush, but most days I'm happy to sit on the veranda and watch the birds come and go in the garden. Then, while sitting there I counted six species of butterfly flitting between the plants, searching for food plants for themselves or to lay eggs on. So, I thought I might grab a few quick shots. No, the sunshine is so hot that the butterflies are all flying almost non-stop and at speed. They are not easy targets.

A female Common Grass Blue Zizina labradus feeds on a clover flower

The male cabbage whites were chasing one another through and over the bushes, then I spotted a female feeding on the dandelions on the lawn. One down. Next the blues, but they are so tiny and they really chase one another, fast and in unpredictable twisty flight. Fortunately this seems to take its toll on the males as they stopped every now and then to sun up and re-charge. No chance of close approach though, a long lens shot only. Similarly for the one female I saw and captured as she supped from the clover.

A male Common Grass Blue takes a short break to bask in the sun

The butterflies are certainly pretty to see, from our perspective, but the most stunning lepidorteran in the garden at the moment is a great big caterpillar, a Batwing Moth caterpillar. This one has grown to over 10 cm and the adult when it emerges has a wingspan well over that. They will emerge from their cocoons at the end of the summer, early autumn.

Batwing or White Stemmed Gum Moth Chelepteryx collesi.. Every spine hurts if it sticks into a predators skin

It is a few years since I saw one of these in the garden, which is good and bad news. Good for me as these insect larvae are protected by a mass of spines which break off into our skin if touched. And they are very irritating when they do, as they are very difficult to see and remove. A bit like pieces of very fine glass. But, then bad for the caterpillars as their main food plant in the garden, the tall red gums have been rather sickly in recent years, due to dry weather and an infestation of lerps (Google that, they are a fascinating life form and a rich source of food for birds).

Six true legs stretch forward, searching for a hold

These caterpillars have such dense spines/hairs around their thorax and head that it is difficult to discern exactly where the head is. It is a tiny section set low, beginning somewhere just in front of the legs. The best clue is their tiny black eyes which catch in the sunshine. But their mouth-parts are so swarmed by hairs, not much else can be made out. Then, of course, like so many caterpillars it is tricky to tell which end is which, as the tail resembles the head, or is it the head that resembles the tail...

A tiny beady eye looks out from beneath all those hairs

This one was not on a gum tree, but wandering across some old cut branches. I reckon that it had fed enough for that stage of its life and it was looking for a place to tuck into while it metamorphoses into an adult moth. Their cocoons are also prickly as they push those spines out thorough the casing. That is a very annoying habit for anyone like me you tends to climb trees. The cocoons are well camouflaged and too easily laid hands upon. Ouch.

So, til autumn....

Now which end was which again?