Morinay, J. | Search bioRxiv

bioRxiv2023

Remote sensing of emperor penguin abundance and breeding success

Emperor penguins (Aptenodytes forsteri) are under increasing environmental pressure. Monitoring colony size and trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when illumination levels are sufficient to capture images, but colony occupancy is highly variable. To correct population estimates for this variability, we develop a phenological model that accurately predicts the number of breeding pairs and fledging chicks, as well as key phenological events such as arrival, hatching and foraging times, from as few as six data points from a single season. The ability to extrapolate occupancy from sparse data makes the model particularly useful for monitoring remotely sensed animal colonies where ground-based population estimates are very rare or unavailable. TeaserThe Emperor penguin becomes the Southern Oceans canary in a coal mine through remote sensing its annual breeding success.

ecology↗

bioRxiv2019

Heterospecific song quality as social information for settlement decisions: an experimental approach in a wild bird

Assessing local habitat quality via social cues provided by con- or heterospecific individuals sharing the same needs is a widespread strategy of social information use for breeding habitat selection. However, gathering information about putative competitors may involve agonistic costs. The use of social cues reflecting local habitat quality acquired from a distance, such as acoustic cues, could therefore be favoured. Bird songs are conspicuous signals commonly assumed to reliably reflect producer quality, and thereby local site quality. Birds of different species have been shown to be attracted to breeding sites by heterospecific songs, but whether they can use fine heterospecific song features as information on producer (and by extension habitat) quality remains unknown. We used a playback experiment in a wild population of collared flycatchers (Ficedula albicollis), a species known to eavesdrop on dominant great tits (Parus major) presence and performance, to test whether flycatchers preferred to settle near broadcasts of a high quality great tit song (i.e. song with large repertoire size, long strophes, high song rate), a low quality great tit song or a chaffinch song (control). Among old females, aggressive ones preferred to settle near broadcasts of high quality tit song and avoided broadcasts of low quality tit song, while less aggressive females preferred to settle near broadcasts of low quality tit song. Male personality or age did not influence settlement decisions. Our results show that collared flycatcher females use great tit song quality features as information for settlement decisions, though differently depending on their own competitive ability and/or previous experience with great tit songs. Our study therefore further illustrates the complex condition-dependent use of heterospecific social information for breeding habitat selection.

ecology↗