Song and Dance

I set a camera trap at a Superb Lyrebird display mound over two weeks in July (13-31^st) and was successful in recording some wonderful song and dancing displays. Male lyrebirds display from a number of display mounds within their territory and females are attracted to them by the song first and then song and dance once they are visible as females approach through the thick undergrowth. The repertoire of the bird’s mimicry of other birds’ calls is, as its name suggests, superb, and enthralling. And how he holds and spreads his elaborate tail feathers is just as mesmerising. Follow this Video link to see a compilation of some of the sequences.

The females lay their eggs in winter, so these displays are performed during the cold months and I have watched them display in the snow. The males play no part in the nest building, incubation or tending of the young. The sexes only meet up for the purpose of mating.

Superb Lyrebirds are famous for their mimicry and although there are well-known film clips of birds imitating cameras and chainsaws, most of the sounds that wild lyrebirds copy are of other local birds that live in the same tall forests. I have only heard one bird imitate a knocking sound that resembled someone hammering on wood, which the bird could easily have heard in the forest. That bird was in the forest of the Brindabella Range near Canberra, the same area where this footage was recorded. It is always a pleasant walk along the tracks in the forest, where the lyrebirds can be frequently heard, but seldom seen as they place their display mounds in dense overgrowth. Hence the reason I deployed the camera, to see what was going on in there…

Male superb lyrebirds sing four different song types with unique associated sets of dance moves, but the individual birds vary their songs and steps and they don’t always dance when they sing (Dalziell et al. 2013, below). As can be seen in this video, they also sing without even raising their tail. The whole sequence of the different songs and dances is very elaborate, but purposeful. As these displays form part of the sexual behaviour, there is probably a strong impulse for the males to sing and dance their best to attract a female.   

Lyrebirds can sing with mimicry away from the mound, such as up on tree branches or logs, but they don’t give mimicry segments of their song while dancing. When singing his full repertoire of mimicry the male in the video stood quite still, and it was once he pulled his tail right over his back and head that he began to dance. This was induced by the presence of a female off camera, and he held that pose and dance sequence all the while a female was with him on or near the mound. In one sequence, he backs off the mound, followed by a female, perhaps, the birds copulated on another mound not far from the one where the camera was set. Each male hase several mounds where they display.

I have not yet worked out the complete list of the bird calls that the lyrebird mimicked, but the main song, mixed with the lyrebird’s own specific song, includes: Yellow-tailed Cockatoo, Laughing Kookaburra, Pied Currawong, Crimson Rosella, Red Wattlebird, Satin Bowerbird and Grey Shrike-thrush. During the intense dances when his tail is fully pulled over, the bird does not mimic these calls, but gives a frantic array of buzzing alarm calls, mimics of the alarm calls of the smaller ground dwelling birds such as White-browed Scrubwren, Brown Thornbill and Eastern Yellow Robin. He even mimics the burring of bird wings, such as when birds mob a predator.

For a more full explanation of  Superb Lyrebird display see these papers by Anastasia Dalziell et al. upon which I have relied heavily in describing the details of the bird’s behaviour in this video. 

Dalziell, A.H., Ppeters, R.A., Cockburn,A. Dorland, A.D., Maisey, A.C., & Magrath, R.D. (2013). Dance choreography is coordinated with song repertoire in a complex avian display. Current Biology 23: 1132-1135. https://www.cell.com/current-biology/pdf/S0960-9822(13)00581-2.pdf 

Dalziell, A.H., Maisey, A.C., Magrath, R.D., & Welbergen, J.A. (2021). Male lyrebirds create a complex acoustic illusion of a mobbing flock during courtship and copulation. Current Biology 31: 1970-1976. https://www.cell.com/current-biology/pdf/S0960-9822(21)00210-4.pdf

Dalziell, A.H., Welbergen, J.A., & Magrath, R.D. (2022). Male superb lyrebirds mimic functionally distinct heterospecific vocalisations during different modes of sexual display. Animal Behaviour 188: 181-196.   https://www.sciencedirect.com/science/article/am/pii/S000334722200094X

 

Southern Highland Wildlife

A week of rain has sent the rivers flowing high in south-east Australia, but the wildlife persists.

Raindrops hang from the lace-work leaves of Narrow-leafed Conesticks Isopogon anethifolius a common shrub on the sandstone cliff edges.

The tight flower heads of the Hairpin Banksia Banksia spinulosa glisten with water.

The unique form of the Mountain Devil Lambertia formosa flowers hold up nectar for the insects and birds.

Mosses, ferns and lichens rich in saturated colours.

A caterpillar of a Common Gum Snout Moth Entometa fervens creeps along a twig, unnoticed by birds. Its feet and the sides of its belly are covered with `hairs' to help conceal the movement. Thanks to Suzi Bond for the ID.

When it realised it had been spotted, it reared up into a threat display, showing its horns, two bright blue bands and upturned tail.

A face on view, but I still cannot make out what or if it is mimicking anything that might frighten away any potential predator.

Down in the gullies, the Superb Lyrebirds were singing. I saw two calling from branches rather than their display platforms on the ground. Neither gave full displays, they seemed to be just marking their territories by their songs.

This bird was quite confiding, as I watched him from a nearby path. He seemed to be quite content to go about his business, stretching out his tail and preening between bursts of song.

They are such magnificent birds, with such magnificent feet.

Thick Bush and Clear Roads

An adult male Flame Robin Petroica phoenicia

Winter is almost over in Canberra and the first of the Spring migrants are moving in, as I have seen on a few recent August days up in the nearby Brindabella Ranges, in the Namadgi National Park. The White-eared Honeyeaters were the most vocal with their chopping calls, there were a few Flame and Scarlet Robins, back from their winter quarters in the lowland paddocks and woodland, but most of the birds had yet to return. 

The forest was rather quiet overall. At this time of year the characteristic sound is that of singing lyrebirds. These birds reside there all year and lay their eggs in mid-winter when snow is on the ground. Their incubation takes several weeks and the single chicks take several more weeks to fledge. So, perhaps they need to lay early to give the young time to grow over their first year. 

A small part of the heavily forested Brindabella range

I first counted lyrebirds in the area in 2001 and 2002, before the catastrophic bush fire which burnt out most of their habitat in January 2003 - over a hundred thousand hectares. As I had those counts, I have been counting them in the years post-fire to measure how their numbers have compared over the years since.

They came back slowly from single birds singing along transect lines, to similar numbers as pre-fire after several years. Now however, their numbers are dropping and on one transect there have been no birds for two years. The reason? One might be because the fire destroyed so many trees and most of the ground cover including the leaf litter, that the regrowth has come up thickly with grasses, shrubs, ferns, and saplings all competing for space. That has created a dense mass of vegetation at ground level. Lyrebirds need leaf and bark litter to forage in for invertebrates, their main food, and leaf litter needs space to collect on open ground.

A Superb Lyrebird Menura novaehollandiae forages on an open part of forest floor

It  is good to see the forest recovering, but it will take many more years for the full structure of the mature forest to re-establish. The lyrebirds will survive, and once the saplings grow tall and shade out the lower plants, the ground cover will open up and leaf litter will build up, then the lyrebirds will have more foraging habitat. 

Thick regrowth smothers the forest floor - no room for leaf litter to collect and lyrebirds to forage

The open ground is also an important habitat feature for other birds such as the robins. The Flame and Scarlet Robins both hunt by perching on a low branch, then swooping down to catch invertebrates they see on open ground. As there is now so little of that under the close ground covering vegetation, they are largely restricted to hunt in what open spaces there are. The main ones being those along the forest roads.

The artificial open ground of a forest road - but leaf litter only collects along the edges 

There were robins hunting along most of the roads, which made bird-watching of them easy. I wondered how many there were hunting in the thick vegetation. However, the bush where I tried to walk in for a look was impenetrable, wandering off the track was not an option. There are some open spaces, and there will be lyrebirds and other ground-foraging birds there. And there will be more in future as the forest grows into shape.

A male Scarlet Robin Petroica boodang hunts from a perch above the forest road

The open roads are also good for insects as they allow sunshine to reach the ground. It is cold up in the ranges and insects benefit from the extra sunshine through the gaps. What amazed me was how the robins were mostly catching small insects that I could not even see. Butterflies were easier to spot as they spend much time basking in the sun. Such as the Australian Painted Lady butterflies that were out sunning themselves last week.

An Australian Painted Lady Vanessa kershawi basks in the sun on a forest road
 (note the specific blue centres to three ocelli on the hindwings)

The Australian Painted Lady is a migrant butterfly and these were probably some of the first to arrive in the area. Soon the forest will be busy, and noisy once the large numbers of migrant birds return. 

Flame Robins are rather smart-looking birds