Flight efficiency in Northern Bald Ibises

Birds face high energy demands during their flight. Some species alternate between flapping and gliding, which should allow them to save energy. We equipped hand-raised Northern Bald Ibises (Geronticus eremita) with data loggers during human-guided migration. We monitored the position of the birds, wingbeats, overall dynamic body acceleration (ODBA), and heart rates as a proxy for energy expenditure. The energy expenditure was significantly affected by the length of flapping and gliding bouts. At a gliding proportion of about 20%, we measured a maximum of 11% saving based on heart rate measurement. This study provides empirical evidence that intermittent flight is energetically beneficial and can reduce the high costs of flights.

You can access the full paper by clicking the button below

Energy consumption as determined by heart rate and overall dynamic body acceleration (ODBA) decreases as the duration of the gliding phases increases

Two PhD positions available at the Doctoral School Cognition, Behaviour and Neurobiology

The University of Vienna offers 2 PhD positions within the uni:docs Fellowship Programme. The two 3-year PhD positions are fully paid and are based at the Department of Behavioral and Cognitive Biology at the Faculty of Life Sciences. The working language of the department is English.  We welcome early career researchers from all over the world. The PhD candidates will be embedded in the newly founded Vienna Doctoral School for Cognition, Behavior and Neuroscience (VDS CoBeNe) at the University of Vienna. The main goal of VDS CoBeNe is quality assurance in PhD training and education. The doctoral school stands for promotion of inter- and transdisciplinary knowledge exchange. More information at https://vds-cobene.univie.ac.at/phd-call/cobene-unidocs-calls/

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Androgen response to simulated intruder in a territorial poison frog

Thirty years ago, an explanation for the facultative increase of males’ androgen levels in response to social challenges was proposed as the “Challenge Hypothesis” (Wingfield et al., 1990). Since then, numerous studies have tested this hypothesis across different animal taxa with diverse life history. We tested the Challenge Hypothesis in the highly territorial poison frog, Allobates femoralis. We compared males’ androgen concentrations between a non-stimulated condition (baseline) and following a simulated territorial intrusion (post-STI) conducted by playing back the territorial call through a loudspeaker. We took advantage of water-borne hormones sampling, a non-invasive technique, to characterize androgen levels, and showed that it closely reflects circulating plasma testosterone levels. Our results demonstrate that water-borne androgen increases after a STI in A. femoralis males only when males approached the playback loudspeaker. Therefore, our results provide novel support to the Challenge Hypothesis in a territorial frog.

This work is a result of a collaborative effort lead by Camilo Rodriguez. You can access the full paper by following this link.

Learned components of courtship

A focus on postural displays, choreographies and construction abilities

Song learning research has provided a plethora of information on the proximate and ultimate explanations for learning of vocal displays. However, sexual displays involve a variety of components including body postures, sequences of movements, and modification of the environment for attracting prospective mates. Although visual displays are widespread and prominent, only few studies have investigated the role experience and learning may play on motor performance of non-vocal courtship signals.

In this review paper, we use the framework provided by vocal learning research as a guide to investigate whether, and how, motor displays may be learned. We review the available evidence which suggests that learning of visual courtship components is more widespread than had been previously assumed, and identify the areas where more research is needed. The full text of the article can be found at this link.

This paper was funded by the Austrian Science Fund (FWF) (W1262-B29), and by the Vienna Science and Technology Fund (WWTF) (CS018-021).

Giovanni Spezie

Cliodhna Quigley

Leonida Fusani

Unshaded coffee plantations impose a heavy load on thermoregulation

The effects of land-use conversion and agricultural intensification on tropical birds have been widely studied, but focused largely on ecological and functional patterns. Replacement of forest with monocultures alters microclimatic conditions throughout the landscape. In this work, we investigated the differences in microclimatic temperatures across forest, shaded and unshaded coffee plantations and studied the physiological impacts on four Neotropical bird species that thrive in agricultural landscapes. Unshaded coffee plantations presented birds with the most challenging thermal environment but all species were able to withstand current maximum temperatures. However, replenishing water lost to dissipate heat in unshaded farms might become a problem if temperatures will keep raising. The full article can be found in this link

Otto Monge

Leonida Fusani

Ivan Maggini

The article is the result of a collaboration with Stefan Dullinger and Christian Schulze of the Department of Botanic, University of Vienna

Ghrelin modifies migratory behaviour in nature

On migration, most passerine birds stop over along the way to rest and refuel. A network of hormones signals metabolic fuel availability to the brain in vertebrates, including the recently discovered gut-hormone ghrelin. Here, we show that ghrelin participates in the control of migratory behaviour during spring migration in a wild migratory passerine. We administered ghrelin to yellow-rumped warblers (Setophaga coronata coronata) caught during stopover and automatically radio-tracked their movements following release. Ghrelin rapidly induced birds to move away from the release site, indicating that the ghrelin system acts centrally to mediate stopover departure. The effects of the hormone treatment declined within hours following release and did not affect the overall rate of migration. These results provide experimental evidence for a pivotal role of ghrelin in the modulation of stopover decisions during migration, and offers insights into the regulatory functions of metabolic hormones in the dialogue between gut and brain in birds.

The study was a collaboration with Christopher G. Guglielmo, Scott A. MacDougall-Shackleton, and Yolanda E. Morbey of the Advanced Facility for Avian Research, University of Western Ontario, Canada, and Hiroyuki Kaiya of the National Cerebral and Cardiovascular Center Research Institute, Japan.

Funding was provided by the Marie Skłodowska-Curie Individual Global Fellowship 798739 GHRELMIGRA to Sara Lupi

Access the full publication here.

Oxytocin and singing

Does singing have different effects on physiology compared to other vocal activities? In a study conducted together with colleagues of the Department of Behavioural and Cognitive Biology, we examined the association of salivary levels of oxytocin, corticosterone and testosterone with different types of activities conduced solo or in group.

Singing and speaking were associated with decreases in salivary oxytocin concentrations, when performed together or alone, however, oxytocin concentrations decreased by less after singing together than after speaking together. Singing together improved self-perceived emotional status and social connectedness more than speaking together.

You can read the full paper here

Linking bird diversity and agricultural management in tropical farmlands

Agricultural intensification, characterized by the loss of native flora and the establishment of monocultures, has been negatively associated with the richness of bird species in tropical regions. However, very little is known about the impact on avian functional roles and evolutionary history across gradients of intensification. In this paper, we analyzed the response of the taxonomic, functional and phylogenetic dimensions of bird diversity inside coffee farms with different management practices. By conducting fieldwork across a ~2000m elevational gradient, we also evaluated the effect of elevation on the response of the bird communities to intensification. We found that the response of the diversity dimensions was linked to specific vegetation elements within the farms, but also to the elevation zone being considered. To learn more, click on this link to access our paper.

A typical coffee-dominated landscape in the mountains of central Costa Rica at middle-elevations

Monge O, Dullinger S, Fusani L, Schulze CH. 2021. Taxonomic, functional and phylogenetic bird diversity response to coffee farming intensity along an elevational gradient in Costa Rica. Agriculture, Ecosystems & Environment, 326:107801. doi: 10.1016/j.agee.2021.107801.

Lab retreat 08/10/2021

Members of the Fusani Lab 2021

After a break of two years, members of the Fusani Lab finally met again in person in the lovely town of Seebarn. After all the lockdowns and social distancing rules, I think we all were more than ready to meet in person again to hear about each other’s research and, even more importantly, to socialize not via a monitor screen. The day started with a fabulous scientific program with talks from postdocs and PhD students. In several sessions, we heard about the fantastic science that is going on in our lab spanning a diverse range of species from local species, such as storks, to Australian bowerbirds. We even heard a talk about Tanganyika cichlids highlighting the diversity of research done in the group.

We not only heard about the latest research but members of the AOC also gave us valuable insights into their ongoing projects and plans for the future.

After the scientific program, we also organised a short ornithological excursion to a nearby pond. There we could enjoy some great water birds and reed inhabitants. The more experienced ornithologists among us could even hear different woodpecker species calling.    

The group retreat ended with a visit to a local Heuriger where we were received with amazing local food and beverages (I think the Sturm will be remembered by some us for a while not just for the excellent taste).

I would like to thank Anne and Leo for organising the retreat, the Seebarn team for hosting us, and all participates for a fantastic and great day. I really enjoyed it a lot! See you next year.

Physiological innovation and courtship behaviour

The evolution of courtship behaviour often requires specializations of neural, sensory and motor systems. In addition, optimized metabolic, respiratory and cardiovascular systems may be required to sustain the neuromuscular demands. However, physiological specializations for one function can create limits on their use for other purposes. Such trade-offs may influence the way courtship develops but may also provide information used by females for mate choice. We review this body of work with an eye towards expanding our appreciation of the evolution of widespread tissue hormone sensitivity and hormone action as the system through which elaborate courtship behaviours evolve.

Click here to access our article in Animal Behaviour.