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Unravelling the drivers of bird carcass removal by vertebrate scavengers at transmission power lines

09 Jul 2021 - Joana Bernardino, CIBIO-InBIO/UP | 14h45
Unravelling the drivers of bird carcass removal by vertebrate scavengers at transmission power lines

Linear infrastructures, such as power lines and roads, have well-documented negative impacts on bird communities. Among those of greatest concern is direct mortality (mainly through collision), which is typically assessed based on regular bird carcass searches along the linear infrastructures. However, assessing bird mortality impacts through simple field-based counts is not straightforward because the number of carcasses found greatly depends, among other sources of bias, on the chance of a carcass not having been removed by scavengers between searches.

We performed field experiments (using infrared camera-traps) and retrieved data from grey literature to investigate the drivers of bird carcass removal by vertebrate scavengers along transmission power lines in mainland Portugal. Most modeling was based on survival analysis techniques (Kaplan-Meier method and Accelerated Failure Time models) which can accommodate time-to-event data, with interval- and right-censoring. We hypothesize that carcass removal times are mediated by ecological factors, such as habitat, season and bird carcass size, but also by the presence of the infrastructure itself, since avian facultative scavengers often use power lines as hunting perches and previous studies suggested that mammalian scavengers actively search for carrion along linear infrastructures.

In this seminar, I will present the patterns of carcass removal identified and their implications for the derived scavenging bias-corrections in bird fatality surveys. The ultimate goal of this work is to improve the design of future carcass removal trials and, consequently, the reliability of bird mortality estimates at linear infrastructures.


Joana Bernardino holds a MSc in Ecology and Environmental Management from University of Lisbon. She is now in the final year of her PhD project, entitle "Improving impact monitoring and mitigation of bird collisions with power lines”, under the supervision of Francisco Moreira (CIBIO-InBIO), Regina Bispo (FCT - NOVA University of Lisbon) and Sara Santos (University of Évora).



[Host: Francisco Moreira, Biodiversity in Agricultural and Forest Ecosystems - AGRODIV]

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