Nest building started this morning in my camera-monitored box just outside the front door. After six years of blue tits this year I changed the entrance plate from 28 to 32mm, hoping for either tree sparrows or great tits. So who has moved in ? Another pair of blue tits! I haven't kept details of the start of nest building for each year but looking back through the video clips and stills I can see it was 27 March in 2010, 29th in 2012, 9th March in 2014 and 29th last year. So this is a late start, presumably because of the recent cold weather. Tree sparrows are already active in some of the other boxes and I have also seen blue tits and great tits in other boxes. As I did last year, I'll make another page (accessible via the Nestbox Camera 2016 tab above) to document day-to-day developments once there is more activity and put a weekly update on the main page here.
Although nest building started almost a week earlier last year, the first egg wasn't laid until 29th April. The first egg hatched on 18th May and the chicks fledged on 5th June. So if the weather improves there is plenty of time for this year's birds to catch up.
Each year I have submitted data from this box to the BTO Nest Box Challenge. Being in the north of the country I expect laying and fledging dates here to be slightly later than average. BTO data below for blue tits show the laying date (first egg) for the previous six years. My dates were 22/04/2011, 24/04/2012, 10/05/2013, 23/04/2014, and 29/04/2015 - on average three days later than the national average.
The female bird builds the nest alone, although several times last year the male bird popped in to have a look as well - perhaps he's in charge of quality control. He does bring in food for the female when she is incubating the eggs and both parents feed the chicks. I'm looking forward to seeing how this year's occupants get on.