Thursday, 25 February 2016

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

Thursday, 18 February 2016

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.

Sunday, 7 February 2016

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.