Field season 2019 is over!

Yet another wood warbler field season (7th in a row!) in the Wielkopolska National Park is over!

Despite lower abundance of wood warbler population at my study area due to mast seeding of oaks and hornbeam last year (intrigued what links seed production and wood warblers? Read here!), the field work went surprisingly smooth. Preliminary results of the experiments I’ve conducted this year are very promising and I can’t wait to dig into the data; stay tuned!

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The wood warbler. © Jakub Szymkowiak

Jakub

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Wood warblers, jays, and mast seeding – new paper!

Our recent paper on how wood warblers (Phylloscopus sibilatrix) manage nest predation risk via informed habitat selection decisions is now available online!

Using a playback experiment, we showed that wood warblers eavesdrop on predator calls and avoid settling at sites with high perceived risk of nest predation by Eurasian jays (Garrulus glandarius). However, the way wood warblers adjust habitat choices to the nest predation risk posed by jays is affected by… tree mast seeding! This is likely due to cascading effects of masting on the population dynamics of rodents and generalist predators, creating temporal peaks of elevated nest predation risk for wood warblers.

If you are interested in the full story, you can read it here and on ResearchGate. Enjoy!

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The wood warbler. © Jakub Szymkowiak

Jakub

On social information use between flycatchers and tits – new paper

tl;dr: It is selective interspecific information use between flycatchers and tits, rather than aggressive interactions, that drives nest-site selection decisions

A series of studies using the so-called Apparent Novel Niche Experiment (ANNE) design has shown that migratory flycatchers (Ficedula spp.) cue on apparent nest site preferences (geometric symbols) and clutch sizes of resident tits (Paridae) to choose their own nest site. These results became textbook examples of selective interspecific information use (SIIU) in wild animals, but their interpretation has recently been challenged. In particular, it has been suggested that SIIU should be rejected, as it is based on several assumptions that have never been examined in the field, or that in some aspects the available field data do not support it. Instead, it has been suggested that the decision-making patterns of flycatchers found in ANNE studies resulted from aggressive interactions, not information use, between tits and flycatchers (termed Owner Aggression Hypothesis).

Several arguments raised against the Selective Interspecific Information Use hypothesis have already been addressed (read here & here) and it is clear that claims to reject the SIIU are premature. However, there are points that still remain open in the ongoing debate, related to flycatchers prospecting behavior and cognitive abilities to assess tit clutch size. If you are interested what I think about these, read my recent commentary that has just been published in acta ethologica!

Jakub