Boxes for Birds and Bats

In late 2019, Adrian Darley, Treasurer of Clapham Common Management Advisory Committee (CCMAC), pitched the idea to CCMAC to install 50 bird and bat boxes across Clapham Common with funding from the Parks Investment Levy. 

Many song birds already nest on Clapham Common but there is a large population of crows and magpies that like to raid nests for eggs and young chicks. Boxes give protection until the young are ready to fledge, that is, leave the nest. 

The boxes are made of a mix of wood pulp, clay and cement which makes them strong and long lasting, and, importantly, difficult for predators to access. 

The plan had been to put them up using volunteers but lockdown ended group volunteer activities so Adrian and his wife Jo took on the task. 

Dr Iain Boulton, Lambeth Council’s ecological expert, and Adrian put up the first one (labelled box ‘1’) near Windmill Drive playground in November 2020. 

Over the following eight weeks Adrian and Jo put up another 47. Every box points either north or north east to avoid the risk of eggs or chicks overheating from direct sunlight. Each box is mapped to help with future monitoring. 

To date, of the 40 tit boxes put up 15 have been used this year – 11 by blue tits and four by great tits. By early June nearly all the young had fledged but on 13th June Adrian heard young chicks calling for food from one of the boxes that was previously empty so it seems some birds are nesting late, probably due to the cold and dry April which would have reduced food availability.  

A number of other boxes are muddy around the nest box hole which is usually a sign of activity so they may get used for a second brood later in the year. 

Most of the literature tells us that although new bird boxes may get used after a year, it is much more likely that birds take 2-3 years to get comfortable with them. In this context the results so far are very promising and support the case for additional nest boxes on Clapham Common. Later this year Adrian plans to map out suitable sites for a second roll out.