Hybrid manakins do hybrid courtship

Research on hybridization has focused mostly on plumage, particularly in taxa like the bearded manakins Manacus spp. that differ from each other mainly for the colour of the collar and of the underparts. By using high-speed videography and slow-motion analysis, we found that hybrids perform courtship displays that are intermediate between the two parent species. In particular, the colour and the choreography show different degrees of similarity with either parent species, suggesting that courtship behaviour is involved in speciation processes in this avian taxon.

The article is in press and can be accessed here.

You can access the corrected proofs with the button below.

Claudia Janiczek wins the prize for the best poster at the PhD academy

Another recognition for our group: Claudia Janiczek won the prize for the best poster at the PhD Academy, an event organized by the CoBeNe Doctoral School of the University of Vienna. Claudia presented her work on the comparison of courtship displays between species of Birds of Paradise.

Christina Krumpholz wins the price for the best talk at the PhD academy

The PhD Academy was launched last year and is aimed primarily at PhD students from the CoBeNe Doctoral School of the University of Vienna. This year, our PhD student Christina Krumpholz gave a talk on the relative contribution of voice and face to person attractiveness in online experiments and in real-life settings, a study she has conducted within our project Comparative Aesthetics. She won the award for the best presentation at the conference!

Cover Image for Ethology – Jan 2023

Our paper Sneaky copulations by ‘apprentices’ bowerbirds made the cover of the journal’s issue of January 2022. Nice to see our work portraited!

Article on reduction of migratory behaviour in Der Standard

If you can read German, have a look at the most recent interview released by Wolfgang Vogl on the disappearence of migratory behaviour in many species of migratory birds that remain in Europe in winter because of climate change.


Giovanni Spezie defended his PhD

After a few adventurous years, during which he had to face droughts, pandemics and wildfires, Giovanni eventually defended his PhD on December 6th. His contributiions on the courtship of bowerbirds and in general about the role of learning in the development of coursthip displays will leave a deep footprint in our lab. Bravo! You can find his publications here.

Sneaky copulations by ‘apprentices’ bowerbirds

Male spotted bowerbirds (Ptilonorhynchus maculatus) build and defend a structure of sticks and straw – the bower. They decorate these nests with colourful objects to attract mates during the breeding season. Certain non-resident subordinate males are tolerated by resident males in their bowers over multiple breeding seasons. Previous research has shown that these male coalitions bring indirect benefits to subordinate males. So far, however, it has been unclear whether lower-ranking males also have direct advantages. Our present study shows that in rare cases the lower-ranking birds benefit directly from copulation opportunities.

The cases were observed in the bowers of spotted bowerbirds during the 2018 breeding season. Several non-resident males disrupted ongoing copulations between the bower-owner and a receptive female, and these events were followed by vigorous aggressive interactions. These observations support the hypothesis that subordinate males are sexually mature individuals who occasionally gain access to females while visiting established bowers.

First observation of extremely rare events

The rarity of such events is remarkable. Extensive observations have been made on spotted bowerbirds for several decades – but so far, no attempted copulation from subordinate males had been documented. The recording of four independent observations in different individuals strongly indicates that sneaky copulations are not an isolated and abnormal behaviour but rather a behavioural pattern or alternative reproductive strategy used by subordinate males.

Beta profits from Alpha – male coalitions are profitable

Male-male coalitions have so far been observed particularly in birds such as manakins, grouse, peacocks, wild turkeys and bowerbirds. A common feature of most courtship coalitions is that a dominant “alpha” male accounts for all or most copulations, while subordinate “beta” males abstain from breeding and have no—or very limited—access to mates. Sacrificing reproductive potential for a male association may seem paradoxical, but it has direct and indirect benefits for the subordinate males. The animals benefit indirectly, for example, from taking over the position of the alpha male after his death or from learning behaviour that is important for successful mating from him. As it turns out, they also derive direct benefits from clandestine mating with females.

The article “Sneaky copulations by subordinate males suggest direct fitness benefits from male-male associations in spotted bowerbirds (Ptilonorhynchus maculatus)” by Giovanni Spezie and Leonida Fusani was published in Ethology. The full text can be downloaded here.

What to measure to predict brain size in birds?

At least in part, the brain’s capacity to process cognitive processes depends on the mass of neural tissue involved – the more tissue, the more information can be processed. In fact, studies often find a positive relationship between brain size and cognitive performance. However, majority of these studies are based on comparisons between different species. Growing number of scientists is now trying to understand how more subtle differences between individuals of the same species are related to their cognitive skills, which is often a big challenge when studying animals in nature.  

A first study in the barn swallow proposed to use external head measurements, which require handling but not the sacrifice of the study subject, as an accurate approximation for brain mass. In this collaborative research with Joanna Bialas and Marcin Tobółka (Poznań University, Poland), we employed this method for the first time in a small Galliform, the Common Quail. We measured both the external head dimensions of the birds as well as the weight of their brains, and tested how well these two measurements were related to each other. Despite we did find that these measurements were correlated, the correlation values we found were not strong enough to allow using external head measurements to predict an individual’s brain mass with high confidence. Moreover, the best predictor of brain mass was not head volume, as previously demonstrated in barn swallows, but the height of the head alone. We therefore recommend validating the original method of external head measurements in each avian species before making assumptions on how these measurements might be related to brain size and cognitive performance.  

You can access a full version of the article here

The work was funded by the FWF Der Wissenschaftsfonds Lise Meitner Fellowship (M2520-B29)

The importance of synchronization in courtship

Male ring dove perching on a window box

Multimodal signals may carry additional information which is missing when component signals are presented separately. We used audiovisual playback of male ring doves’ courtship to investigate female response to display stimuli differing in their audiovisual timing. We created a shifted stimulus where audio was shifted relative to video by a fixed value and a jittered stimulus, where each call was moved randomly along the visual channel. We presented females with a same stimulus type, that is, control, shifted, or jittered, for 7 days. We recorded their behavior and assessed pre- and post-test blood estradiol concentration. We found that playback exposure increased estradiol levels, confirming that this technique can be efficiently used to study doves’ sexual communication. Additionally, chasing behavior (indicating sexual stimulation) increased over experimental days only in the control condition, suggesting a role of multimodal timing on female response. This stresses the importance of signal configuration in multimodal communication, as additional information is likely to be contained in the temporal association between modalities.

You can access a full version of the article here

Funded by the Vienna Science and technology Fund (WWTF) grant N. CS18-021

Sweet sap, savory ants

Birds, the descendants of carnivorous dinosaurs, lack part of the sweet receptor found in mammals. This should leave them insensitive to sugars. However, recent studies have shown that both hummingbirds and songbirds have regained the ability to sense sugar by repurposing their savory receptor to now detect carbohydrates in fruits and nectar. How other birds sense sugars, and the extent to which taste receptor responses track the immense dietary diversity of birds, is unclear. To investigate this question, Julia Cramer and Maude Baldwin from the Research Group Evolution of Sensory Systems at the Max Planck for Ornithology/Max Planck for Biological Intelligence, together with colleagues from the Cornell Lab of Ornithology, Meiji University, the Swedish University of Agricultural Science and our lab focused on woodpeckers. Although primarily insectivorous, this group of birds also contains multiple species that include sugar-rich sap, nectar, and fruits in their diets.

Using behavioral tests of wild birds, the team showed that woodpeckers clearly prefer sugar and amino-acids over water. Surprisingly, wrynecks – a member of the woodpecker group whose diet is almost exclusively composed of ants – displayed preferences for amino acids but not sugars. Functional analyses of taste receptors confirmed that woodpecker receptors were sensitive to sugars, whereas those of wrynecks were not. Interestingly, ancestral reconstructions indicated that the common ancestor of wrynecks and woodpeckers already possessed a modified savory receptor capable of responding to sugars. A meticulous dissection of differences between wryneck and woodpecker receptors revealed unexpectedly that changes in only a single amino acid in the wryneck receptor selectively turned off sugar-sensing: the birds kept their ability to taste savory, which is likely important for insect-specialist birds that consume a protein-rich diet.

These results trace an evolutionary history in which an early gain of sugar sensing in woodpeckers —possibly arising in an earlier ancestor and therefore older than woodpeckers themselves — was followed by its reversion when the wryneck receptor was later altered. Further investigation will be required to describe how specific changes in taste receptors, and in other physiological and sensory systems, are related to the rich dietary diversity across birds.

You can access the full version of the paper here.