Black-eared Cuckoos

A first-year Black-eared Cuckoo on the left, adult on the right

In a recent post I discussed the plumage of a Black-eared Cuckoo Chrysococcyx osculans which we caught at Charcoal Tank Nature Reserve, then last weekend, 14-15 December, we caught the same bird again, along with two younger birds which were definitely in their first year. A useful comparison.

Once again I am grateful to Mark Clayton who organised the trip as part of a long-term study of birds in the area.

The second first-year bird

One of the first-year birds

The adult bird (right) as described in the earlier post, had a fully marked face and a richly coloured throat and breast.

 

Both first-year birds had faintly marked faces, with dull throat and breast colouring.














The moult sequence and timing of the various feathers of this species is poorly known, with the information used for the synopsis in the Handbook of Australian, New Zealand & Antarctic Birds being based in parts on only a sample of three birds. And we only have a sample of three. Therefore, I am open to discussion on any points raised.

The two young birds on the left have dull grey-brown rumps and tails; the adult bird on the right has a grey
rump contrasting with a dark tail. The first-year birds have faded feathering overall, while that of the
adult bird is fresh, unfaded and lustrous like other birds of the genus

Although synchronous growth bars on the tail are used as an indication of a bird with its original tail feathers, it seems from comparison between these birds that the adult bird might not really have synchronous bars. Perhaps the feathers can grow and align to seem to be of the same age. The freshness and dark unfaded colouring of the adult bird's tail would seem to be recently grown. Yet, apart from the apparent synchronous tail growth bars, the bird has an otherwise adult plumage. Also, its tail is only slightly worn at the tips, and it has distinct white tips, as mentioned in the previous note, unlike the first-year birds which both have well-worn buff tips. Such bold white tips (compared with buff tips of definite young birds) are often an indication of an adult bird. I suggest that this is indeed a true adult bird which hatched at least two breeding seasons ago, and the first-year birds hatched one breeding season ago.

The first-year birds also had faded, frayed secondary coverts with buff tips, and darker, unfrayed primary coverts

There is another trip to Charcoal tank planned for January, so perhaps if we catch these or any other Black-eared Cuckoos we will be able to note any moult  features which could help to determine this species moult pattern. 

Platypus

A typical view of a Platypus on the surface between dives for food

Last week I was out at Tidbinbilla Nature reserve in the ACT, specifically to look for Platypus Ornithorhynchus anatinus and I saw three. The ponds and dams there are probably one of the best places to see these wonderful animals. Although mostly nocturnal, they do come out to feed around midday and if the water is calm and the light flat under an overcast sky they can be spotted paddling around on the surface between dives for prey.

The best way to spot them is to watch for ripples on smooth water

It is always tricky to capture a sharp image of a Platypus as their fur is always slick with water and they glisten in bright light. But it is simply satisfying to sit for a while and watch them as they carry on with their lives, quietly and unobtrusively. A trip out to Tidbinbilla is a true escape from the increasingly bustling city of Canberra.

Platypus are quite common but easily overlooked

Fan-tailed Cuckoo egg in Scrubwren clutch

A Fan-tailed Cuckoo egg with two of  Large-billed Scrubwren

I was down in the Shoalhaven area a few days ago and while out for a walk through some riverside forest I found a Large-billed Scrubwren Sericornis magnirostris nest. I saw the adult bird flush as I walked by and was surprised to discover that it had built its nest inside an old nest of a Yellow-throated Scrubwren Sericornis citreogularis - on subsequent research I discovered that this is common behaviour of the species. Then when I inspected the eggs there was a cuckoo egg amongst the scrubwren clutch. The egg were likely from a Fan-tailed cuckoo Cacomantis flabelliformis  - as scrubwrens are common hosts of these birds eggs and young, and there were a few of these around the area, but no other cuckoo species.

The cuckoo egg is noticeably larger than those of the scrubwren

There were two scrubwren eggs, but whether there had been three and the cuckoo had taken one out is not known. The cuckoo egg was quite a good mimic of those of the scrubwren, although slightly larger and more spotted overall, and a little lighter in background colour. The scrubwren eggs also had more defined rings of spots around the broad end, especially one of the eggs. There was a faint ring around the cuckoo egg, but not very distinguishable.

The cuckoo egg has a faint ring of spots on the broad end like those of the scrubwren eggs,
but much more general speckling

The nest was a simple relined structure inside the old Yellow-throated nest which looked old as the leaves in the structure were dried and deteriorating. 

The clutch was in an old Yellow-throated Scrubwren nest

The nest was set about head height, c 190cm, and typical of a Yellow-throated Scrubwren in being suspended from a the end of a thin branch over an open patch of forest floor -in this case a footpath, although often they are hung over stream lines.

The nest was suspended over a human track through riverside forest 

Red Bellied Black Snake

Never blinking concentration

While walking with Lachlan through Tidbinbilla Nature reserve in the Australian Capital Territory yesterday, he noticed one, then a second and even a third snake lurking in the undergrowth between the path and the waterside of a small lake. They were all Red-bellied Black Snakes Pseudechis porphyriacus, one of my favourite species of snake in Australia as they have a rich shiny black top side and a fiery red belly - and I have never seen an aggressive one.

A glimpse of the beautiful red belly of the snake as it slipped over a path

The first one glided onto and across the path to drop into a patch of marsh where it carried on hunting for frogs, lizards or whatever else it might eat. The colour on its belly was more easily seen as it crossed the open path than when it slipped through the grasses.

Hunting in the waterside grass

That one was about a metre and a half long and the others about two metres, perhaps one female and two males. But why are people obsessed with the length of snakes, their size does not make them more dangerous (unless they are very large pythons which could kill a human if given a chance). These Black Snakes are very venomous, yet they were quietly getting on with their life and as we left them alone, they left us alone. No one has been recorded as being killed from a bite by any of  this species. 

There was an appropriate visitor sign in the reserve which said 'the only good snake is a live snake' and I for one agree. We just need to be careful if they are around. 

This one would lift its head up to see, or scent for prey, but I don't know why it spread its hood as I didn't approach it.
This is usually a sign to back off, so I did anyway.

Around Eden

Humpback Whales - mother and calf

Last week I went on a trip down to Eden on the south coast of New South Wales, primarily to go out on a boat trip to see the last of the whale migration pass by, and also to see some local birds of the area - on land as well as at sea. And we had splendid close-up views of two mother and calf pairs of Humpback Whales. They were quietly cruising across the bay outside the fishing port of Eden.

Short-tailed Shearwater - note feet protruding beyond the tail

Although the boat trip was primarily aimed at whale-watching, we saw several species of seabirds including the most numerous -Short-tailed Shearwater Puffinus tenuirostris. While the whales were on their way south to the Antarctic for the southern summer, these birds were on their way back to their nesting burrows on offshore islands around Australia, having just returned from as far as the Bering Straight where they spend their non-breeding season.

A few shearwaters landed behind the boat in anticipation of bait being thrown out - as done on some birdwatching trips

I will post more detailed accounts of birds seen on the trip later, but for now I draw attention to what for me was the bird of the trip - the Southern Emu-wren Stipiturus malachurus. I like these birds because of their tiny size, generic wispy tail and overall adaptation to life in grassy heaths. They can be difficult to find in amongst the grasses, but it is well worth listening out for their thin trilling calls. A seemingly simple, yet marvelous bird.

  

The distinctive silhouette of an Emu-wren

Both form and colour are unique, as is their character.

An adult male Southern Emu-wren in full colour - a rather smart bird