A tale of two thrushes

In mid-November, friend Mazza sent me the first of several ‘birdie bulletins’ – she was so excited about the nesting of a pair of grey shrike-thrushes (Colluricincla harmonica) and the subsequent hatching of the eggs. The pair were nesting in a hanging basket right outside her bedroom window.

The Australian Museum says:

The grey shrike-thrush searches for food on the ground, generally around fallen logs, and on the limbs and trunks of trees. It has a varied diet consisting of insects, spiders, small mammals, frogs and lizards, and birds’ eggs and young, and some birds have been observed feeding on carrion. Fruits and seeds may also be eaten on occasion. …

Grey shrike-thrush pairs generally remain together for life and inhabit the same areas throughout this time. Breeding territories of up to ten hectares are maintained. The nest is a cup-shaped structure of dried vegetation, and may be constructed in the same site year after year. Both birds share the nest-building and incubation duties, and both care for the young birds.

The bird itself is pretty drab-looking, but its song is lovely and very distinctive – you can hear it on this website. In fact, I can hear one at home right now. Grey shrike-thrushes are well used to being around people, and it is not unusual for them to build their cup-shape nest of dried vegetation in and around human structures – in rafters, garages, buckets and even potted plants. Mazza has had them nest on speaker shelves high up on the veranda walls.

I can’t tell the story any better than Mazza’s own words, below (slightly edited), from her Birdie Bulletin.

(13/11/21)  A month or two back, our local grey shrike-thrush was spotted with some nesting material in his or her beak; not sure whether the bird I saw was male or female. Then I noticed that a prelined but still empty hanging basket, near my back door, had a nest in it. Watching more closely it became clear that’s what the grey shrike-thrush (herein referred to as ‘Birdie’) was building. (‘Birdies’, as we’ve fondly call these for years, are the most fabulous sounding songbirds, rating second only to the butcherbirds and magpies.)

Then I didn’t see him or her for a while, and thought they’d made wiser plans of nesting elsewhere. (The hanging basket was next to the most frequently used door in the glasshouse, being under the edge of the carport and at ‘business end’ of the glasshouse – you can see the white frame of the door to the left in the first photo.)

A while later I looked at the untended nest and felt it had evolved some more. Days later I saw a pale egg with brown-mottling in it; then the next day two eggs, etc etc.

So now Birdie is sitting on a nest with four eggs in it, and I’ve stopped using that door to minimize disturbance. He or she flies off whenever there’s nearby disturbance, as if to draw attention away from the nest. I understand that grey shrike-thrushes are monogamous, and both share equally in the incubating of eggs.

Location of the nest – in a hanging basket

(13/11/21) Here are the next photos I took of Birdie’s nest with the latest laid eggs. Each egg was laid at least one day after the last.

(15/11/21) Birdie’s sitting fine, although I can never tell when it’s mum, or when it’s dad.  I’d moved some of my amenities to the other side of the glasshouse, and stopped using the side door next to the nest, to minimise my disturbing her or him.

I’ve just had to disengage a passionfruit vine which had thrown a tendril around the ‘nest’ basket’s wire. With gusty winds cropping up of late, the vine was going to jossle the basket more than the wind alone.  I just talked to Birdie soft and low, trying to deal with it at as much distance as possible, and (s)he just sat there!

Also recently, I was doing something near where the hanging basket is, and I saw Birdie fly to the nest, look at me, and promptly return to sitting.  Prior to that, if ever the sitter saw me, it’d fly off (which is why I’ve been avoiding the ‘business end’ of the carport etc where the nest is).  So now I’m ‘bird-whispering’ whenever I’m approaching, and no longer putting off things I need to do there.

I’ve also become very protective. Normally I don’t discourage any native fauna, but I shooed a female koel (a type of cuckoo) [eastern koel, Eudynamys scolopacea] off from nearby trees; she wasn’t in direct line of sight of the nest, but I wasn’t taking any risks! (The koel flew a considerable distance away, and when I thought more about where she flew from, I realised she was probably only eating fruits from a native tree.  But I didn’t want her to find the nest at all.)

The first photo is taken from my bed within the caravan ~ with just the caravan wall between us, I sleep a couple of feet away from the nest, at a level slightly above it, hence the photo looking down at the nest.  When I nestle down at night, I feel like I’m sharing her experience, being so close. You can see the bed-end of the caravan in the last two photos. Hatching is due any day now, certainly by the weekend.

(17/11/21) We have three out of four hatched eggs.  Interestingly, there are no remnants of the broken shells left in the nest.  Both parents are feeding in rotation. I’m watching to see what, if anything, happens to egg #4.

One of our Bulletin recipients has been inspired to hang some lined-only baskets around her place.  Mine are all lined with paperbark first, then the coir ‘cups’. Ironically that came to be to prevent birds pulling coir out from the sides, to build nests elsewhere!  (Poor plants!)

By same token, whenever I clip my long-haired dogs (Lhasa apsos and Maltese), there’s a wealth of very soft nesting material I leave distributed at various points under trees, near bushes etc.  I know the finches use it, I’ve seen it woven with cobwebs in the nesting structure. I don’t yet know if anyone uses it as a soft lining.  Another interesting point about grey shrike-thrush nests is that they are lined specifically with small roots.  Not very cosy, but creates lots of little gaps/airspaces, that the outer nesting structure doesn’t have.  Maybe it’s something to do with ‘nest hygiene’ – droppings? The nestlings take about 15-16 days to fully fledge. The eggs were between the sizes of 5c and 10c coins.  The adult bird is > 21 cm long (up to 25 cm). So that’s a lot of feeding and rapid growth.

P.S. The hatchlings hardly make any sound till within days of being fully fledged!

Newly hatched

(18/11/21) Early this morning I saw one Birdie turn up, feed the Birdie sitting on the nestlings, and (s)he in turn appeared to feed the bubs, whilst the visiting Birdie flew off.

Later on, when the morning sun was well on the nest, and the sitting Birdie looked a bit hot (beak open, so possibly panting, just like a dog – I’ve seen kookaburras do that on 45 degree days), the other birdie turns up, with what looked like an insect in its beak, and directly proffered it to the bubs, then settled in to cover them. (I don’t know that the bubs took in the proffered tucker).  In the meantime ‘hot’ Birdie had flown off, presumably for a food-finding break and a drink of water.

Later again, I watched whichever Birdie was on the nest, and saw throat movements that could have been regurgitatory.  Not sure if s/he was feeding them or not, but suspect so.  If she was, she was quick at raising her head to make more of the same throat movements.

The parents are so busy now, with coordinating their comings and goings, I’m not sure the chicks will be left alone long enough to get another photo, perhaps until there’s at least some pin feathers protecting them.  This afternoon’s cold wind isn’t helping either. So I haven’t seen the bubs since the ‘newly hatched’ photos.

I’ve now checked below the nest, and found no trace of eggshells, so I can only assume that Birdies ate the remnants after the chicks hatched  (a good strategy for disguising existence of the nest, aside from recycling the nutrients!)  Then a zoologist friend tells me they do take the shells out of and away from the nest, along with their ‘poo packets’.

The parents have just started singing their more melodic songs for the first time since they were just building the nest.  The only call I’ve heard in the interim has been their alarm call, usually when the sitter has flown from the nest when disturbed.  So as I sit at my computer typing this, I’m hearing the most clear and lyrical serenade, amplified by the roof over the caravan and the carport.  This is heaven!

One day old

Changing of the guard – parents swap places

<19/11/21) Well, the nestlings are now 3-4 days old, and, oh my, have they grown!

It was hot here today, so my camera caught a time when no Birdies were sitting.

We definitely have three bubs, with the fourth egg still in the nest.  (But you can’t see the fourth egg in today’s photos, because the bubs are covering it – compare the first photo (earliest of bubs) and second photo (today’s) – amazing what 3-4 days’ growth does!)

Apart from dark skin, there remains a sparse dark down.  (Chooks would at least have pin feathers edging their wings by now, but wouldn’t (I don’t think) have increased so much in volume. (Memory test anyone? It’s a while since I bred chooks too!)

The other remarkable thing about the bubs, is their eyes are huge relative to the size of their skulls.  It’s not very clear from the still shot, but it was very evident in observation, because the eyes were moving a lot under their closed eyelids.  Fascinatinger and fascinatinger!

And not a drop of poo in the nest proper! (A bit of parental whoopsy on bark well out of range of the chicks!)

Who says nature’s perfect?  But it’s still amazing!

Four days old

(22/11/21) Today I took more piccies, as the pin-feathers had clearly lengthened, in under 24 hours.  The rain has not interrupted the daily routines of parents coming and going.  And the bubs can be seen snoozing peacefully when nobody’s actively sitting, even when it’s raining!  I imagine this warmer weather allows the parents to have more breaks than I was expecting.

The bubs are starting to make very quiet sounds, sort of murmurings more than anything more distinctly birdlike, and only occasionally.  Eyes are still closed and they’re hardly active at all. When they are, it’s mostly when an adult turns up and they open their gapes, as if to say ‘feed me, feed me’!  (However, they are well into deep breathing – those body movements are very obvious.)

6 days old – pin feathers emerging

7 days old – pin feathers on wings, tail, and thickened down generally

Last photo at 8 days

(27/11/21) There’s no nice way of putting this, so I will just say it like it is.

A raptor (bird of prey) took the egg and two chicks from the nest, very late afternoon. I stayed with the nest till dark when I noticed there was only one left, and the raptor (some type of hawk) did land on the nest to get the last one, but it got told where to go and it went!

It didn’t come back during the night, but did snatch the last chick the next morning. The attached is the last photo taken, a couple of hours before the predation. Their eyes had just started opening on occasion.

It’s been lovely sharing the joy, but nature has some pretty harsh realities, and this has been one of them. There is a chance Birdie will breed again this season, so I’m working on ways to make any repeat nesting more visually obscure, including extra lined but empty baskets, under better cover.

So sorry that it ended this way.

Fortunately, according to Backyard Buddies,

It is not unusual for grey shrike-thrushes to have one to three (or even five if there is enough food) clutches in a breeding season. So if these birds build a nest near you, you could be enjoying their company again and again as they come back to raise new chicks.

So cheer up if you can, Mazza. Although this story had a sad ending, there’s an excellent chance your birds went back to breeding very shortly after. This is why the grey shrike-thrush is one of Australia’s most widely spread birds.


Postscript: Mazza says:

I now have a couple of similar hanging baskets completely suspended under roofing. (Birdies fly into the car-port to sing sometimes, as if to amplify their sound and appear more formidable to competition.)

In case they do decide to return to their original nest, it is now obscured by a cone of newspaper, held up by the hanging pot’s three chains. The bit of branch was added to make it a bit more open, and to ensure any heavy rain run-off is shed away from the nest.  From my observation, their previous nests have all been open-topped; they are definitely not hollow-nesters; so this may be too ‘covered’ for them. It may even deter them from using the original nest again.  We may yet get to see.

UFOs identified

Unidentified Floating Objects can be a bit of a challenge to identify. By the time they reach shore and are washed up, features have often been pecked off or removed by wave action, or the creature has just rotted away and what’s left is a bit of a mystery. In the case of the latter, a rotting whale carcass washed up on a beach may sometimes be mis-identified as some sort of fabulous sea monster.

Hundreds, possibly thousands, of clear, stiff, gelatinous ‘medallions’ have been washing up at Ballina – and, it turns out, in many places along the east coast.

In my quest to find out what these are, I emailed Ceridwen Fraser, associate professor in the Marine Science Department at the University of Otago and author of a new book called Beachcombing.

In her book, I had noticed a photo of a salp, which looked somewhat similar, but she thought my critters were jellies. She kindly put me onto the Facebook post of Coolum and North Shore Coast Care, which says:

These jellyfish are a relatively new species called Aldersladia magnificus, a genus and species within hydromedusa and within the Aequoreidae family found in tropical and subtropical waters (Gershwin, L. 2006).

What causes these blooms to happen? There are multiple causes, some contributing factors are ‘Eutrophication, climate change, overfishing, and habitat modification’ (Qu CF, Song JM, Li N. 2014).
When washed up they appear to have no tentacles, but when seen in the water they have long tentacles that can retract. These tentacles can sting so please be careful whilst swimming at the moment. Don’t be too scared though, Jellipedia rates them as a 1/5 on their sting-o-meter.
 
they are … bioluminescent. If you head down to the beach at night time at the moment to a spot where there are plenty of them you will see for yourself.

In 2006, Lisa-Ann Gershwin identified the new genus and published a paper, ‘Aldersladia magnificus: A new genus and species of hydromedusa (Cnidaria: Hydrozoa: Leptomedusae: Aequoreidae) from tropical and subtropical Australia’, and if you want all the gritty details you can download it for free from here.

Thank you to Ceridwen for pointing me in the right direction. It’s great fun finding and tracking down things I haven’t seen before. Now I can add one more thing to my bucket list: a salp!