Sunday 1 June 2003

Blue Tit Parus caerulus Behaviour

We did not put up our new nest box until 30 March 2003. A bit late in the season, but better late than never, we hoped. So, we were surprised but very pleased when within a week a pair of Blue Tits had begun visiting the nest box regularly. These visits were generally brief, with one bird (we were not certain if it was the male or female) perching at the circular entrance hole, looking into and occasionally entering the nest box. After a while we noticed that the dark brown wood-stain around the nest box entrance hole had been chipped away. Closer observation over the next couple of days revealed that one of the birds would perch at the nest box entrance and peck at the surrounds until the bare wood was revealed. Occasionally, the Blue Tit would perch in the entrance and peck at the inner edge of the hole. This behaviour continued for the next three days, with the pale scar slowly increasing in size, until it was approximately double the size of the entrance hole. We think only one bird was involved in this behaviour, but cannot be sure. The other bird of the pair was usually perched in a nearby lavender bush.

I have checked other nest boxes currently occupied by Blue Tits, nest box photographs from a variety of sources (????) and television footage (Gardener’s World) and have not seen similar scarring on any of the nest boxes. Male Blue Tits are reported to tap around the entrance of a nesting hollow when trying to entice a female (BWP) but I can find no reference to such extensive “re-decoration” of the nest entrance.

During nest building in the nest box, the Blue Tits paid frequent visits to the window frames of both our and our neighbours’ houses, most frequently to the upstairs windows but occasionally downstairs too. We could not determine what the birds were collecting or eating when we observed them through binoculars. We could not see any insects when we made a close inspection of our kitchen window frame where the Blue Tits had been seen and decided they were probably collecting spiders webs for nest building.

This nest box lid was difficult to remove, so we kept our investigations of the nest box contents to a minimum. The nest was complete when we looked on 8 May 2003. By 23 May 2003, the adults were paying frequent visits to the nest box suggesting the young had hatched. We heard the young for the first time on 27 May 2003. Following the hot dry spell at the end of May, all adult activity had ceased. When we checked the nest box on 1 Jun 2003 it contained one dead chick and one unhatched egg.

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