Do cows look where they put their foot, and will they avoid their own dung? And might this be a reason for Black Larks to use dung around their nests, to save it from trampling? These are the questions we want to answer by doing our so-called ‘trampling experiment’. As we showed in our last blog post, we made over 200 clay ‘cookies’ to be put in and outside dung piles in a grid, after which we let a herd of cattle graze in the grid.
With the help of the local Kolya on horseback, we managed to let a herd of cattle (91 cows) graze in our 1 hectare grid. Instead of driving them trough the grid, we wanted the cattle to take their time in the grid. We expected that in this way they will be more attentive where they step. The cows took their time in the grid while we waited, relaxing in the grass. After an hour we slowly drove the cows out of the grid and counted the result. About 10% of the cookies had been trampled, and by far most of the trampled cookies were the ones places on bare soil, so not in dung piles. We will definitely repeat this experiment, but for now it seems that cows are careful not to step in their own dung!
Already for some time we are placing temperature loggers in and outside empty nests (either predated or successful) to compare the nest temperature with the outside temperature. This week we took this one step further by adding dung pieces to the side of the nest and repeating the measurements. In this way we hope to get a better idea of the effect dung has on the nest microclimate.
During May we were lucky to have Gera with us one the project, who was an enthousiastic field worker and provided us with essential help for contact with locals. Yesterday she went back home, to continue working on a project on bird victims due to power lines. Thank you very much, Gera! Thijs and Thomas still have a month to work on experiments and find nests – up to the 100!
|Most nests have 3 to 4 eggs, but this nest surprised us with 5 eggs!|
|While the cattle grazed, we could relax|
|Kolya helped us with getting the cattle into the grid, many thanks!|
|And another team picture :)|