Birds, beetles and singing in the car
Snow is still falling outside, and a thick layer of clouds hangs over Freiburg, but slowly and surely days become longer and the next field season approaches. It is for sure a good time to remember last spring and to look forward to many more crisp and sunny mornings in the Black Forest. Despite all the difficulties that the pandemic brought, it was also a season of achievements. With the help of a wonderful team of field assistants, the B6 project managed to visit all of our 135 plots to carry out bird counts (and a majority of them twice!), and to extend sampling efforts beyond taxonomic boundaries, deploying pitfall traps for ground-active invertebrates on 66 plots. We aim with this to obtain comprehensive measures of community composition and relative abundance of invertebrates at the ground level, and to better understand how these link both to forest structures (retention-related ones but not only!) and to ground-foraging bird species.
The ground-foraging guild makes up a small share of the Black Forest bird assemblage, but a more meaningful one in old-growth forests and in other parts of the world. While retention has little benefit for this guild in areas where clearcutting forestry is the rule (e.g. in Scandinavia), the same might not be true in Central Europe, where forests are dense and continuous, with few openings, creating very homogenous ground-level conditions. Most species foraging for invertebrates at the ground level are quite eclectic in their choice of food, but, still, abundance of their preferred prey are likely to be more limiting than caterpillars, for instance, are for species foraging in the forest foliage. Large carabid beetles and spiders are of particularly high nutritional value, but while large carabids are at home in shady and moist forest, spiders favour sunny areas with dense low vegetation. Is then a more heterogenous forest one that can provide more and more diverse food for birds, and thus house more individuals and more species of ground-foraging birds? After many early mornings in the field and days sorting invertebrate catches in the lab, we hope to find some answers to these questions.
In the meantime, many good memories were made, brightening up our days amid a very chaotic outside world: coming across a displaying capercaillie male near one of our plots (and almost being attacked by it!), finding our very first colourful beetles in the traps, singing out loud driving up and down the winding mountain roads, or having lunch sitting in meadows that looked like a painting. And we hope this year is going to bring even more of those :)
by João Manuel Cordeiro Vale Pereira (B6)
