Bill colour preference does not play a major role in the sub-species barrier between red- and yellow-billed long-tailed finches

In the paper published in Ecology & Evolution, we report on experiments in which we assessed mate choice by both females and males for members of the opposite sex with bills colours that were either the same as their own, or those of the alternate sub-species. These findings differ from those found in some other hybridising species, where colour signals make an important contribution to pre-copulatory species barriers. The findings help us to understand the evolutionary processes that maintain the divergence between the two forms in the wild across northern Australia. The full paper, led by Callum McDiarmid, and part of his PhD on speciation in this species, can be found here.

The Distribution of the two sub-species of the long-tailed finches across northern Australia with the shading indicating bill colour, with a narrow hybrid zone between the two forms.

Despite the lack of clear assortative mating on the basis of bill colour, the displacement of the contact zone illustrated above in orange, with the area in which most of the genomic divergence occurs (shown with a dashed line), suggests the introgression of the bill colour genes from the west towards the east. This finding can be partly explained by the potential dominance of at least some of the genes for bill colour. In our study we report the findings from experimental crosses between the subspecies in captivity where the colour of the bill in female F1 hybrids is dependent on their father, supporting this idea.

4 PhD opportunities in Avian Evolutionary Ecology in Sydney, Australia

1 PhD scholarship on ‘Mitonuclear incompatibility and speciation in Poephila finches’ 

3 PhD opportunities: ‘Physiological adaptation to Lead (Pb) contamination in an urban bird’; ‘Personality and behavioural responses to a lead-contaminated environment in an urban bird’; ‘Spatial and behavioural ecology of the endangered black-throated finch’.

We offer 1 full scholarship for an Australian candidate (or competitive International candidate), on the first project listed above (recently supported by ARC funding). For all other projects International or Domestic (Aus/NZ) candidates will be supported in their applications to apply for competitively awarded Macquarie University Scholarships. All projects will be based at Macquarie University, Sydney, Australia.

Sydney is a global power city rated in the world’s top-ten for economy, research and development, cultural interaction, live-ability, environment, and accessibility. Macquarie University is a major research-based institution situated in the heart of Sydney’s high technology precinct. It is considered one of Australia’s best universities and is rated among the top 1% of universities globally. 

School of Natural Sciences, Faculty of Science and Engineering, MQ, is a vibrant community of teachers, researchers, professional staff and students working across a wide range of disciplines including animal behaviour, climate change, conservation, ecology, evolution, genetics and genomics, physiology, and environmental science. 

The PhD’s will all be based in the research group run by Prof. Simon Griffith (https://griffithecology.com), and will be supported by his international collaborators in Europe and the US. 

Projects

Mitonuclear incompatibility and speciation in Poephila finches 

This project is focused on captive and wild populations of Poephila finches that are endemic to northern Australia. This project will examine the incompatibility between the mitochondrial and nuclear genomes, its effect on mitochondrial respiration, and how that contributes to the species barrier between divergent forms. The work is in collaboration with Daniel Hooper (US) and Antoine Stier (France), and will use bioinformatics and physiological assays mostly in the laboratory. 

Physiological adaptation to Lead (Pb) contamination in an urban bird

We have identified resistance to lead poisoning in the population of house sparrows in Broken Hill, Australia’s oldest and largest mining towns. This project will examine the molecular and physiological mechanisms that allow sparrows in this population to thrive in this heavily contaminated environment, providing a case study of evolution in an urban/industrial environment. This project will be based in the field and laboratory and use a combination of molecular and physiological assays.

Personality and behavioural responses to a lead-contaminated environment in an urban bird

This project will focus on the house sparrow population of Broken Hill and investigate the personality traits and spatial and behavioural ecology that permit sparrows to thrive in the heavily contaminated areas of the town. The project will largely be based in the field, in the town of Broken Hill, NSW. 

Spatial and behavioural ecology of the endangered black-throated finch

There is an urgent need to understand the spatial and behavioural ecology of the southern black-throated finch, one of Australia’s most iconic endangered birds. The work will be focused on a remnant population of birds near Townsville and investigate movement ecology with automated radio-tracking in parallel with studies of breeding and behavioural ecology to identify key vulnerabilities. The work will be in collaboration with Lyanne Brouwer (JCU, Townsville, QLD), and require long periods of fieldwork. 

References

Poephila speciation

Lopez KA, McDiarmid CS, Griffith SC, Lovette IJ, Hooper DM (2021) Evaluating evidence of mitonuclear incompatibilities with the sex chromosomes in an avian hybrid zone. Evolution, 75, 1395-1414; Hooper DM, Griffith SC, Price TD (2019) Sex chromosome inversions enforce reproductive isolation across an avian hybrid zone. Mol Ecol, 28, 1246-1262. 

Urban contamination

Andrew SC, Taylor MP, Lundregan S, Lien S, Jensen H, Griffith SC (2019) Signs of adaptation to trace metal contamination in a common urban bird. Sci. Total Environ50, 679-686. 

Black-throated finch conservation

Reside AE et al (2019) How to send a finch extinct. Env. Sci & Policy 94 163-173. 

Qualifications

We are looking for a candidate who:

  • holds a (research) master degree or honours degree with distinction* in a relevant field, such as Evolutionary Biology
  • is curiosity driven and passionate about fundamental research in the context of evolutionary ecology, and strongly motivated to obtain a PhD degree
  • is proficient in the English language* 
  • is a team player, willing to work with a diverse group of researchers and technicians, and can also work independently 

*Specific requirements as (see: https://www.mq.edu.au/research/phd-and-research-degrees/how-to-apply)

Ideal candidates will also have some of the following

  • previous experience of bird ringing (or animal handling) and conducting fieldwork in harsh environments 
  • strong quantitative skills in statistics and bioinformatics 
  • have strong communication skills and motivation to disseminate results to both scientific peers and a broad audience

Conditions

Macquarie University offer an MQRES Scholarship, for the duration of the PhD. The scholarship comprises the equivalent of a full-fees award and stipend at the current rate of AU$ 32,000 per annum.

Application
The selection procedure will proceed in three stages:

  1. First application (17/02/23)
  2. Development and submission of full application (International 03/03/23; Domestic 30/04/23) Assessment by selection committee (mid-June)
  3. Start of PhD enrolment for successful candidates (07/08/23)

Please submit your initial application via email to simon.griffith@mq.edu.au before 11:59 pm 17th February 2023. Provide the following in your application:

  1. Cover letter (1 page max.): a letter introducing yourself, describing your motivation and qualifications to conduct this scientific research, and your expectations of the PhD programme
  2. CV (2 pages max.)
  3. Academic records (transcript of undergraduate degree and a certified copy or scan of your MSc or honours degree certificate. 
  4. Proof of sufficient competence in English e.g. IELTS, TOEFL scores. (unless your degree was in an English speaking country)
  5. Names and contact details of two academic references
  6. Initial research project idea: brief description of the research question(s) that you wish to address with respect to the advertised topic and your approach to address the research question(s) (300 words max.)

Applications that do not satisfy the requested format will not be taken into consideration. 

Macquarie University, is committed to providing a working environment where each individual is valued, respected and supported to progress. Our priority is to ensure culture, policies and processes are truly inclusive and that no-one is disadvantaged on the basis of their Aboriginal and Torres Strait Islander identity, gender, culture, disability, LGBTIQA+ identities, family and caring responsibilities, age, or religion. We encourage everyone who meets the selection criteria and shares Macquarie University’s values of scholarship, empowerment and integrity to apply. Learn more about our progress towards Equity, Diversity and Inclusion: https://staff.mq.edu.au/work/diversity-and-community.

Information

For information you can contact:

Zebra finches help to shine a light on the social function of bird song

In a paper published today in Current Biology, we have characterised the very social nature of song in the zebra finch, and this helps to highlight the fact that bird song is not always about competition over mates and territories. In the study, led by Hugo Loning, a student in Marc Naguib’s research group in Wageningen University (Netherlands), we have analysed the expression of song over several years and in a variety of contexts. The study is an amalgamation of data collected by remote acoustic recorders every three days at Fowlers Gap for several years, across a lengthy drought, and periods of breeding and no breeding activity. The main finding are that zebra finches sing a lot regardless of the season, or condition of the local environment. Males usually sing in the presence of their female partner (who they are typically paired with for life), and also in close company with other males. We believe that our findings should place a greater emphasis on the social function of birdsong more generally, and that it is a useful signal for the coordination of activity across a population of birds. Our findings are in contrast with the great majority of studies of bird song that emphasise the competitive nature of bird song.

There is a piece written about the work in Macquarie’s Lighthouse magazine which includes some video of singing males.

Assessing the danger of climate change to birds

Tito’s first paper was published today in Conservation Physiology. The paper, which includes some of Tito’s data, is a response to a recent model that had evaluated the likely effects of climate change on some of Australia’s birds. In our response, we used data from our study of the zebra finch to argue that the assumptions that are commonly made about the effects of a warming climate on birds are often over simplistic and aren’t able to account adequately for the adaptive responses that birds are likely to make. For example, in the paper we show that one of the important responses that birds will make on extremely hot days is to drink significantly more water than normal. If birds can stay adequately hydrated they are able to use that water to reduce their body temperature significantly and guard against hyperthermia. We also argue that there is an urgent need to get better physiological data from the zebra finch and other species to improve the value of predictive models in the future. The climate is changing and more extremely hot days are likely. That does cause a significant challenge for birds and there will be a tipping point for survival at some temperature. That point is likely to be slightly higher than the one predicted by earlier models though given the remarkable adaptive responses that we have demonstrated in the zebra finch. The full paper can be found here.

When it gets hot zebra finches drink more, and make use of the many artificial water points across the arid landscape such as this stock watering trough. (photo: Simon Griffith)

Tiarne’s thesis submitted

 The physiological effects of high blood lead levels in the House sparrow 

Congratulations to Tiarne Harris who submitted her MRes thesis today. Well done on all the amazing work you have put in over the past 12 months. I’m really excited about the results that you have found in the Broken Hill sparrows and the future research directions that they have stimulated.

Tiarne (left) and Lori out at Lex’s in South Broken Hill collecting some of her data.

The evolution of colourful eggs

It is great to see Kiara’s paper now published in Evolution (it can be found here). The paper is focused on the evolution of colour in eggs and uses the Australian passerines to provide insight into the emergence of pigmented eggs in different branches of the family tree. The passerines, are the songbirds, and they make up about half of the world’s species of bird today. This group first evolved in Australia, and the continent is still home to the largest number of passerine families, and can provide insight into what was happening early in the radiation of the group.

In this study we characterised the egg colour variation across different families of Australian songbird, and were able to identify that the ancestral egg colour in the passerine group was most likely to be white, and that pigmented eggs emerged independently in a number of different branches of the family tree over time. Importantly, this seems to have happened after the ancestors of the different families evolved open nests. This makes sense, because the pigment likely evolved to help protect the now exposed eggs from predators and from solar radiation.

This paper builds nicely on the earlier comparative work that was started with Jordan Price, when he visited on sabbatical and Daisy Englert Duursma.

Fig 2. from L’Herpiniere et al 2021, showing how the evolution of colour in the eggs of different species, maps nicely on to the distribution of closed and open nests across the phylogeny of Australian passerines.

Singing it softly

Singing male Zebra Finch. (Photo Hugo Loning)

Zebra finch song is an extremely short-range signal. That is the conclusion from the recent paper by Hugo Loning in Behavioral Ecology. This is the first paper of our project on acoustic communication of the wild zebra finch in collaboration with Marc Naguib from Wageningen University. After quantifying the song amplitude of wild zebra finch recordings, we played them back at natural amplitude and re-recorded them in our field site Fowlers Gap. Afterwards, we analysed these transmitted vocalisations while integrating what is known about the hearing from lab zebra finches. This way, we found out that the detection distance of song is on average about nine meters – an extremely short distance for song. We supported this claim by observations in the field which confirm that group members are often very close, on average within one meter, when a group member is singing. Additionally, we find that even their ‘distance call’ does not reach very far, up to about fourteen meters. Our reported findings are in stark contrast with the classical idea of birdsong as a long-range communication signal. The paper can be freely accessed here.

Cover Page Model

It clearly helps to work on an amazingly beautiful species when it comes to getting a cover page photo for a study, and once again a journal has chosen to use a picture of the Gouldian finch to grace the cover. Here is the August cover of the Journal of Experimental Biology with a great photo supplied by Mark Chappell, one of the co-authors of our new paper. The paper, led by Bill Buttemer demonstrates that although the red and blackheads morphs have some quite different behavioural strategies there is no difference in their basal and maximal metabolic rates.

A male black-headed and male red-headed Gouldian finch.

Mitonuclear incompatibilities in the two subspecies of the Long-tailed finch

It is really great to see our first paper in this exciting space being published with the paper by Kelsie Lopez being published in Evolution. The paper can be found here. In this paper we report the molecular work that Kelsie did with Daniel Hooper at Cornell, finding a divergence in the mitochondrial sequence of two clades that arose around 0.5 million years ago. This is the kind of spilt that recent theoretical work has suggested might help to drive speciation, and the incompatibility of two closely related forms (lots of cool work by Geoff Hill, and Paul Sunnocks in this area). This spilt in mitochondrial haplotypes is coincident with the Z chromosome divergence that we found earlier, and centred around Kununnurra in the Eastern Kimberley. Hybrid zone females are significantly less likely than males to carry an admixed Z chromosome or have mismatched Z-mitochondrial genotypes, which is a strong indication that there is some cool selection happening here. So a female that has a western Z chromosome, will work better if she also has a western mitochondrial haplotype. Females with a mismatch, like a western Z chromosome and an eastern mitochondrial haplotype are probably less fit and tend to perish at an earlier stag of development. We are following this up with more work in the field and laboratory.

Figure 2. From Lopez et al 2021.

Sperm, eggs, and nestlings – 2 days, 3 papers!

The past few days have been particularly productive for the research group with three quite different papers all published online over the past 48 hours. First up was the paper published in Ibis reporting the catastrophic mortality of nearly all embryos, during a heatwave back in 2017. The paper was written by Luke McCowan and myself, and describes this heatwave and the very high level of mortality throughout the population at this time. We will publish more detail on this one very soon.

Second up is the first experimental paper focused on data from the Oroboros Oxygraph machine that we have used to assay mitochondrial function. This paper, published in Frontiers in Physiology, was led by Riccardo Ton, and is focused on the experiment he conducted while first visiting us as an Endeavour Scholar in 2019. The paper is published online and is publicly accessible here.

Finally, less than 12 hours after Riccardo’s paper is the SpermSizer paper written by Callum McDiarmid. This paper, published in Behavioural Ecology and Sociobiology describes a new tool for measuring sperm morphology. The program has been extremely useful in processing the many thousands of sperm that we have now measured in our studies of estrildid finches. The paper can be found here.

Figure of Sperm Sizer in action. From McDiarmid et al 2021.

Why are pair bonds so strong in Australia?

The first fieldwork I ever did in Australia was focused on the silvereye. On my first day in the field, having worked in Europe up to that point, I was so struck by this pair allopreening that I took this photo (on the left). Since that time, one of the questions that I have worked on, has been why pair bonds in Australian birds are so different, and much stronger then those exhibited by similar birds in Europe.

Recently I published a review of empirical work in this area in Frontiers in Ecology and Evolution. The paper is open access, and can be downloaded here. We are continuing to conduct research in this area, with one of our main projects being a collaboration with Marc Naguib from Wageningen, focused on the pair bond and acoustic communication between partners in the zebra finch (pair shown on the right above).

How do Zebra finches cope with heat?

drinkingZF
Drinking zebra finches (Picture: Simon Griffith)

In two papers recently published with our collaborator, Dr Christine Cooper from Curtin University, we have looked at the physiological mechanisms through which zebra finches can cope with the extreme conditions that occur regularly at our field site, and specifically air temperatures in excess of 40 degrees Celsius. The papers, published in the Journal of Experimental Biology and Comparative Biochemistry and Physiology, Part A, help us to understand how birds adjust their physiology to cope with such challenging conditions. Zebra finches were better able to cope with heat waves when they were primed by similar conditions, and reduced their metabolic rate, thus lowering the amount of heat being generated internally. Individuals also showed great plasticity in their use of water and their body temperature, enduring short periods with elevated body temperature when required. It is not surprising that these desert adapted birds can cope so well with these hot and arid conditions, but understanding the mechanisms that they can use, and the flexibility that they have helps us to understand likely responses to climate change in desert birds, and the reasons that mortality events have been reported in these and other desert specialists. It is likely that those heat induced deaths have been caused by unpredictable bursts of high temperature, which the birds were not able to prepare for.