Schwegler are the best nest boxes on the market, made from natural woodcrete they give excellent insulative values for the nesting birds and this encourages a high occupancy rate - the highest of all nest box manufacturers. All Schwegler boxes come with a 25 year warranty that is in addition to your usual rights. They are simple and effective.
The House Martin nests come in two forms, the single and the double, this design is used extensively throughout Europe and is easily fixed under the eaves of your house. Unlike natural nests it will not crack or fall down and will not be affected by traffic vibration.
House Martins are a sociable bird and will naturally want to use nests that are in pairs or more, these nests can be arranged in groups to form colonies.