Bird count, promising results

Why be interested in the birds of the Crau?

As you probably know, the LIFE SOS Crau Grasshopper project includes a large number of studies to increase and preserve the populations of this unique insect in the world.

Among the actions implemented in this project, one concerns the reduction of predation by insectivorous birds, potential predators of the species. Thus, in order to gain a better understanding of the distribution and abundance of birds, but also to characterise the risk of predation in the various grazing areas, a count of several target species was carried out in the spring of 2022. This data will be one of the parameters influencing the choice of sites for the reintroduction of the Crau Plain Grasshopper.

A well thought-out organisation

For this participatory science operation, nearly 40 volunteers responded to the call for participation. They were supervised by 4 employees of the PACA CEN 13 and the CA13. This strong mobilisation made it possible to carry out this operation successfully.

In order to meet the objectives of this action, our volunteers were spread out over 24 observation sites on the edge of pastureland and 6 of them had the task of following a shepherd and his flock.

The target species for this count were insectivorous birds that could potentially be predators of the Crau Plain Grasshopper. These include, among the corvids, the Jackdaw (Coloeus monedula), the Black Crow (Corvus corone), the Rook (Corvus frugilegus), but also the Cattle Egret (Bubulcus ibis), the Yellow-legged Gull (Larus argentatus) and falcons, in particular the Lesser Kestrel (Falco naumanni) and to a lesser extent the Common Kestrel (Falco tinnunculus).

Our rigorous volunteers carried out this inventory by doing 5 minutes of observation and counting every 15 minutes!

Promising results!

The count generated almost 5,000 records of target species, and 48 species (target and non-target) were identified.

Thanks to this study, we now know that the abundance of certain species is linked to the presence of a flock of sheep. Indeed, we note a strong presence of cattle egrets (79%), as opposed to jackdaws (16%), in the vicinity of flocks.

This count also allowed us to learn more about the distribution of insectivorous birds and thus to deduce the predation pressure on the different sites. Out of a total of 2,366 ha, only 13% of the area targeted for the reintroduction of the Crau Plain Grasshopper is subject to high predation pressure, 23% to moderate pressure, and 64% to little or no pressure.

Rather promising results for the reintroduction of the Crau Plain Grasshopper!

In addition to these encouraging results, it should be noted that this action made it possible to raise awareness of the Crau Plain Grasshopper problem among some forty people and to discover the ornithological wealth of the National Nature Reserve of the Crau Cushions. This inventory also contributed to the development of the skills of novice observers and to encourage exchanges within a network of amateur ornithologists in the region. Lastly, this count enabled the volunteers to be introduced to the emblematic species of the Crau and to strengthen the links with the shepherds.

We would like to thank all the volunteers for their involvement, their seriousness and their motivation, which made this operation a great success!