For centuries people have been using mineral resources without complying with consequences of the negative environmental impact. Until recently, it has been assumed that the destruction of specific habitats is an irreversible process. However, in global and European scale, practice shows different, more encouraging results. In many sand quarries, after revealing the layers and formation of vertical walls, there are excellent conditions for the development of breeding colonies of two very interesting species of birds - Bee -eater and Sand martins .
Sand quarry of Kaolin AD in Dabravino is a lifeline for the sand martin. In 2007, in field settled several pairs of sand martins. The first year they were about 20 in number and raised offspring without being influenced by the proximity of the running technique. Kaolin AD took immediate action to carry out the extraction, consistent with the breeding season for migratory guests. Four years later, thanks to ecooriantation of the staff working in this quarry , there are impressive results - a colony of nesting sand martins is increased to about 150 breeding pairs. Due to poor regulation of the rivers most of the natural habitats of these birds have been destroyed, but a sand quarry of Kaolin AD with its soft and sheer walls, with its environmentally friendly company actions, provides excellent conditions for their reproduction.
Sand Martin (Riparia riparia), class r Passeriformes /, Family Martins / Hirundinidae / is a monogamous bird - couples are retained for life. It nests on vertical earth banks of rivers and other water bodies, where its name originates. It selects areas with a loose and soft soil. The nest is a horizontal hole in the vertical slope with a hole 6-8 inches long and 1,5 m. Both birds dig it on shifts with their feet.
In the end is nesting chamber, which represents a slight extension. In the nesting chamber is very nest itself, it is built of straw, moss, dry grass, feathers and down. They lay 2-5 white eggs. Both parents incubate for 13-15 days. Small birds leave the nest after about three weeks; the parents feed them with insects. Unlike other martins, they most frequently grow only one brood a year. They live in flocks on the outskirts of freshwater ponds and rivers and marshes, rich of small flying insects. They eat mostly flying insects, mosquitoes, flies, dragonflies, which catch during the flight. In Bulgaria, the Sand martin is protected by law as the Biological Diversity is included in Appendix № 3.