The 70 boxes spotted around the site at Brimham are built to attract blue and great tits, pied flycatchers, nuthatches and redstarts. We also have several open-fronted boxes for spotted flycatchers, thinnish boxes for tree creepers and larger boxes for owls. We monitor the boxes on behalf of the British Trust for Ornithology (BTO), completing record cards for each bird box. After the cards have been completed we send them to the BTO, who compile all the information in the bird trends report, which is a telling review of our environment.
The rangers and volunteers start looking in the bird boxes around mid-April and visit the boxes throughout the spring, usually every 7-10 days. First they check for any nest building, usually shown by some moss with blue tits, who are always the first ones to build their nests. After a couple of weeks the nests become lined with hair and are fairly complete. Shortly after building their nests they lay their eggs, which can be buried beneath down feathers (to hide them from predators) while the birds are out feeding. The blue tits can also be quite aggressive and have even been known to spit at the team.