Lyrebird nest - raided

While surveying singing lyrebirds in the forest on the Brindabella Range near Canberra, which included recording the displaying male described in the previous post, I also checked the progress of the lyrebird nest shown above. The nest was set on a small ledge about three metres up a small crag, which is about five metres high. The rock wall is not easy to climb up as it is slightly overhanging below the nest. As soon as I saw the nest I knew something was wrong. The top of the domed nest had been ripped off and lyrebird feathers, which the female uses to line the nest to keep the single egg warm, had been scattered across the ledge and below the crag. 

The damage can be clearly seen in this second photograph. The nest is typical, formed of a large ball of sticks, larger than a basketball. This is lined with moss and then feathers, the smoky grey body feathers, which the female plucks from her belly. All three components can be seen to have been ripped open and in the third photograph, below, the single egg can be seen lying in the depths of the nest cup which once had a warm sheltered dome over it. Lyrebirds typically lay only one egg, incubation takes seven weeks, and the chick remains in the nest for a further six weeks. 

This was clearly the work of a predator that had probably managed to climb or jump down from the top of the crag onto the top of the nest. The potential predators of lyrebird nests in the area include fox, wild dog or feral pig when a nest is on the ground, and suger glider, greater glider, possum or feral cat if the nest is off the ground. A fox could climb to some nests, but I don't think they could reach this one. Footage from a trail camera set at a lyrebird nest by Matthew Higgins has revealed that a sugar glider can take an egg from a lyrebird nest, so a greater glider or possum could likely take one too. This suggests that a native climbing predator would have taken the egg if it had opened this nest. But it would have taken considerable strength to rip the nest open and the egg was left behind. There was a tiny needle point hole in the egg, possibly made by a claw. A fox would have taken the egg. So, that leaves the likely suspect to be a feral cat, as a cat would be more likely to have been after a young or adult bird on the nest. As obligate carnivores, they prefer to eat meat. Fortunately, there was no evidence of the adult lyrebird having been killed, but this breeding attempt had failed. 

Feral cats have done so much damage to Australian wildlife.  

 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