We inspected all thirteen boxes in early May and found that there were signs of activity at eleven of them!
Five had moss and cups lined with feathers inside; a pair of nuthatches were busily bringing leaves to another; two blue tits and one great tit had laid eggs and two boxes had an adult blue tit sitting tight and glowering at us. A bumble bee was occupying one of the mossy nests and the pair of coal tits seen nest building in April had been usurped by blue tits.
One nest had eight cold eggs inside. British Trust for Ornithology research shows blue tits have one of the largest clutch sizes of all birds - up to 16 eggs! However, most clutches contain 8-12 eggs. Blue tits lay one egg a day until incubation starts a day before the clutch is complete. This helps ensure the young hatch within a couple of days of each other and can fledge at the same time. We hoped that these cold eggs were part of an incomplete clutch being held in suspended animation, rather than a deserted nest, and this proved to be the case.
We completed a second inspection of all the boxes later in May. There were tiny chicks in six nests. Blind, featherless and with huge bright yellow mouths or ‘gapes’. Another nest contained eggs and an eighth box had a great tit sitting tight.
The parents have been constantly flying in with caterpillars and insects to feed the young and leaving with faecal sacs of white poop to keep the nest clean. Nestlings are very well trained and poop right after being fed. The poop is held in a capsule of mucus that is sufficiently robust for the adult to pick it up in its beak and carry it away from the nest.
Eight out of thirteen nests with eggs or young - this is amazing progress for our first year!!!
Andrew Darby
FoPV Bird Surveyors Group