Busy and busier
Life gets a bit crazy this time of year. It seems like every creature in the forest is busy with something to do with reproduction - seeking a mate, defending territories from rivals, building or finding a home for its offspring or gathering food for them.
And we go a bit crazy trying to record all of this activity!
Here are some vignettes of forest life we’ve observed over the last few weeks.
[For a view of similar events taking place on a different landscape scale, see Kerri’s blog.]
Pairing up
Flower wasps waste no time in getting down to the business of finding a mate - illustrated by a lucky observation we made of a pair of mating Catocheilus wasps. This sequence of photos tells the story.
It starts with the flightless female emerging from the burrow in the ground where she began life. We first noticed her climbing an Amperea stem at around 1:15pm on 22nd November.
As she does so, she releases pheromones to attract males, which are flying around searching for a mate. Kerri has detailed this remarkable behaviour of wasps in the subfamily Thynninae (flower wasps) in an earlier blog.
We missed the moment of his arrival, but 40 minutes later we saw that a male had joined the female.
He was already coupled with her at that time and the pair remained in this conjoined state on the plant stem for over 10 minutes. She arched her body to explore the end of his abdomen with her mouthparts - perhaps ensuring that their attachment was secure.
She then pulled herself up to a position face to face with her mate.
He began feeding her nectar he had previously gathered from flowers. Being flightless, the female depends on the male for access to a food supply. You can see him feeding her mouth to mouth with his spoon-like extended mouthparts.
The story ends with the male climbing to the top of the stem and flying off - with the female dangling from his rear end.
This video shows the mating sequence from feeding of the female to departure from the site of coupling. I have spliced together sequences from about 5 minutes of activity to make this 1 minute video. But I haven’t sped the action up - the movement of the wasps is really this rapid!
Where to then? In some species, the male transports the female to a flower to take a nectar meal.
The female can now feed herself as she remains coupled to her mate - as shown in this photo of a different flower wasp species visiting teatree flowers.
Eventually the male will return the female to the site where he found her. She digs into the soil, searching for a scarab beetle grub.
She paralyses the grub with a sting, drags it deeper into the ground, constructs a chamber and lays an egg on it. The larva that hatches out feeds on the grub and develops into a new adult wasp. Back to where we started…
Nest building
Red-browed Finch
Once the business of finding a mate and copulation is dealt with, the next task is to find a place to put your eggs - assuming of course that you lay eggs, rather than bearing your young live.
If you’re a parasitoid like a flower wasp, that place will be on the body of another animal. Otherwise (e.g. if you’re a bird), you’ll need to make a nest.
Red-browed Finches construct a flask-shaped nest in a bush - here, often a Geebung (Persoonia linearis) - from grass or flower stems.
They fly to their nest site with a long stem - often several times their body size - hanging from their beak. It’s quite an extraordinary sight - comical but cute.
I’ve previously documented the nest building activity of these finches. But I had another chance this spring when on 18th November I noticed a pair starting to nest in a Saw Banksia (Banksia serrata) bush close to the house.
This bush is about 4m tall and has regenerated from a plant that was burnt in the January 2020 bushfire. Their chosen nest site (arrowed) is 1.4m above the ground.
I placed a chair at a respectable distance from the bush and oriented it so I could record the final part of the flight path in one plane of focus.
I focussed manually on that single plane, set the shutter to rapid multi-frame and crossed my fingers (figuratively) as I hit the shutter.
The finches were flying back and forth quite frequently - at times every 2 minutes - as they constructed the nest. So I had plenty of opportunities to get decent shots.
spot the finch returning to the bush
The finches flew rapidly from their nesting site and went to ground 10-20 metres away to search for a suitable plant stem. This typically took them a couple of minutes.
They would cut the stem at its base and then fly straight back to the nest, holding it in the beak.
Their entry to the nest was almost as direct and rapid as their exit, although they had to brake suddenly before landing. The new piece of material was then woven into the nest.
Two different sequences of nest entry are shown in these photos. In the first - the most usual - the bird flies straight into the nest with its prize.
In the second, the finch first lands on an outside branch and transports the plant stem into the nest site a minute or two later.
On one occasion, the finch collected a bluebell stem with the flower still attached. The flower snagged on the banksia foliage as the bird attempted to fly into the nest.
This sequence shows how it then flew out holding the end of the stem, then flew in reverse to successfully free the offending flower.
Recording their flight on video was too tricky. However I made a gif from a series of still images taken at high speed to show how the finch approaches the nest.
Just a day after they started, the job was done and the finches went quiet.
This is a view of their completed nest showing its classic funnel shape with a low opening.
If I approached the nest too closely one would dart out and rapidly fly away.
They have to be careful not to betray the presence of their nest. Nesting currawongs are currently searching for food for their pair of youngsters and finch eggs or nestlings would make a nice snack.
Incubation takes 2 weeks for these finches, so I can probably expect to start seeing the adults flying back and forth with food deliveries for the chicks in the next few days.
Noisy Friarbird
Noisy Friarbirds have previously been only sporadic migratory visitors to our forest. This year they arrived in early spring and they’ve hung around to breed. Their raucous chuckling and cackles have been a constant reminder of their presence.
Two weeks ago we spotted their nest towards the end of a high branch in a tall Angophora floribunda tree. It is constructed from strips of stringy bark and is well hidden in foliage. I always have trouble relocating it.
The nest was clearly close to completion because the birds were busy collecting dead casuarina needles to line it.
Feeding
It’s not surprising that all animals - invertebrate and vertebrate - spend a lot of time seeking food at this time of year.
They need to feed themselves to keep their bodies in prime condition for reproduction. And soon if not already there will be the appetites of new offspring to satisfy.
Here are some examples of feeding activity we’ve seen in the forest in the last few weeks.
Satin Bowerbird
One of our most common shrubs, the Geebung (Persoonia spp.) produces abundant quantities of a good-sized, nutritious berry in spring. As the berries ripen they fall to the ground.
Our resident Satin Bowerbirds take full advantage of this very accessible food supply.
We see them daily picking up berries, squeezing the fruit in their beak to dislodge the tough skin and swallowing the flesh-covered seed.
fruit of the Narrow-leaved Geebung (Persoonia linearis)
There is a particular biological imperative for the female bowerbird to keep herself well fed. Nest building, incubation of the eggs and feeding of the chicks are her responsibility alone.
The male remains at his bower after mating and tries to attract a new female. They’re definitely not monogamous birds!
Yellow-faced Honeyeater
At this time of the year Yellow-faced Honeyeaters supplement their diet of nectar and insects with forest fruits. The berries of Leucopogon affinis, a very common shrub in our forest are a favourite of this bird.
As the berries ripen they change colour from green to yellow to orange to red.
They make an attractive sight on the bushes. The red ones don’t hang around for very long as the honeyeaters regularly visit the bushes seeking the ripest fruit.
Much of this bounty will be fed to their chicks in a nearby nest.
A host of insects on teatree flowers
This time last year I recorded the attractive power of the flower of the Prickly Teatree, Leptospermum continentale for many insects - see crowds at a nectar bar.
The wide circular bowl of these flowers, ringed by stamens on upright stalks makes their nectar and pollen available to almost all insects. In contrast, many other flowers have shapes that restrict access to a limited range of insect species - as Kerri has described in a recent blog.
This year I revisited the Prickly Teatree but also checked out Burgan (Kunzea sp.), a related species in the family Myrtaceae which is now flowering heavily.
I wanted to find out how many different insects are using these teatree flowers as a food source.
Here is a selection of images of the insect visitors, grouped taxonomically. To date I’ve seen 33 species in 25 different families. I think that’s a pretty impressive level of diversity!
The Kunzea blooms in these photos can be readily distinguished from the Leptospermum flowers - their stamens sit on much longer filaments.
Burgan (Kunzea sp.) bush in full flower
Order Hymenoptera (Bees and Wasps)
Order Coleoptera (Beetles)
Order Diptera (Flies)
Order Lepidoptera (Butterflies and Moths)
Order Orthoptera (Katydids, Grasshoppers and Crickets)
