Bluetit Diary    Mar 2014 (4)

 

 

Sunday 23rd March 2014

Over on Wild About Britain, there has been some discussion about how long a blue or great tit takes to build its nest.  In the Overview page on this web site we have been recording when nest building starts and when the nest has been completed for every year since 2001.  The problem is what do you mean by nest building?

The shortest time between these two dates that we have recorded occurred in 2005 when a pair of great tits who were clearly desperate, built a nest from start to finish in 4 days.  This was unusual because although the pair was interested in the nest box before they took it over on 10th April, the female was reluctant to go inside when the hole was set at 28mm.  Directly I increased it to 32mm, she was happy!

A suitable nesting site is normally found by the male, who then has to entice the female into the nest box so she can approve his choice. Directly he has done this the male leaves her alone in the box.  This process is repeated many times before nest building starts.

Competition for good nesting places is intense and as a result when a pair have chosen their future nesting site the female tends to spend a lot of time playing at nest building by bringing nesting material into the nest box and taking it out again.  This process, which can start as early as the first week in February, helps with pair bonding with the male, as at this time he is still popping into the box from time to time, and makes it clear to other birds that this box is spoken for.

The dates given in the Overview for the Start of Nest Building are probably not very well defined as nest building play slides gently into nest building in earnest, but the difference between the two dates typically varies from about 3 to 6 weeks.

This year the nest in Box1 was started around 4th March ...

... and was more or less completed 14 days later on 18th March.  No doubt a few feathers will be added if the opportunity presents itself, but this is something that is done when feathers are available and then takes no significant time at all.

The nest in Box2 was started a few days later on 11th March ...

... and was more or less finished on 19th March.

Unfortunately, although both bluetits and great tits occasionally look at Box3, and sometimes even go inside it, no pair of birds appear to have adopted it as their future nest site.

The droppings that are inside the box are the result of a male bluetit who roosted in it for several nights last December.

A bluetit's first egg is not normally laid until between about 10th and 24th April, and great tits seem to be a bit later than this.  The latest date we have recorded for the start of egg laying is 9th May when a great tit pair took over a bluetit's nest that had been deserted.  Apart from this unusual event, the latest date we have recorded for the laying of a first egg is 26th April and this occurred in 2013.