The 50 boxes spotted around the site at Brimham are built to attract blue and great tits, pied flycatchers, nuthatches and redstarts. We also have two open-fronted boxes for spotted flycatchers and an owl box. We monitor the boxes on behalf of the British Trust for Ornithology (BTO). After the cards have been completed we send them back and the BTO 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 up to eight times throughout the spring, usually every two weeks. 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!
Following the blue tit it’s time for the arrival of the great tits with their nest building, and finally the pied flycatchers. The time scale for all these activities is usually two weeks once the eggs have been laid, then two weeks for the chicks to grow and fledge. In 2017 Brimham had three male pied flycatchers who claimed their boxes and spent weeks calling for a mate, displaying and flitting around quite vigorously, but sadly no females. We even saw one chase off a redstart from his claimed box. Tree-creepers have also been spotted around the other bird boxes so the rangers are looking to introduce a box specifically for them. There are a lot of nuthatches in the local area but for some reason we haven’t seen any at Brimham Rocks.
The rangers along with bird box volunteer Rob have made most of the boxes on site in the workshops, and have to work constantly to repair them and keep them in good order. Squirrels often attempt to break into these cosy homes and some of the boxes just disintegrate. There can be quite a few casualties during the laying season with some eggs being abandoned, most probably due to the adults being predated; eggs can also be eaten by small mammals and some just don't hatch.
In spring 2018 we had 209 chicks fledge from the Brimham Rocks bird boxes and in really exciting news redstarts, which are an amber listed species, have returned to a nest box after a year’s absence. The team have also recently tried introducing owl boxes to Brimham and while the owl box was uninhabited in 2017 this was likely due to the fact it was put up quite late. Owls usually pick their nest sites for the following year during the winter months so our hopes for this year are high.
Brimham Rocks has a varied and diverse number of birds that breed and visit the site not only during the breeding season but also in the winter. Bird monitoring is a useful scientific study and is a reflection upon the environmental health of the area. The team always looks forward to this time of the year with huge anticipation and excitement.
