Shrikes and wheatears, new research

This is a red-backed shrike video.

Translated from an article by Erik van der Spek, on birds in the dunes of Texel island in the Netherlands:

Red-backed shrike and wheatear have been chosen for this study because they being predators, are at the top of the food pyramid in the dune grasslands. So, when they will do well, the entire food chain should be in order.

Results

The red-backed shrikes are hurt more by a scarcity of flowers than the wheatears. Red-backed shrikes eat more flower visiting insects than wheatears do. Wheatears can catch for the second clutch chicks only about half the protein and fat compared to the first clutch chicks. In June and July there are too few insects which are suitable as food for the baby wheatears. Important prey animals of the wheatear have been found to benefit from somewhat more drift-sand like conditions in the dunes. With the antler moth (caterpillars) and Melanotus punctolineatus beetle doing very poorly in the Netherlands, only 50% of the food supplied by wheatears consists of these animals. That results in too few chicks fledging.

Management?

The opinion of the researchers is that the grasslands should be varied. Not only short and open, but a variety of local drift-sand pits, short dune grasslands, more overgrown areas and floral parts. Flowering herbs on the verges of paths may be important for bumblebees and other bees and butterflies and, as a consequence, for the birds that eat them. When the rabbit population will increase, there will be less need for cattle grazing. …

The research into the management of the dunes is still continuing.