The Story of a Hole in a Tree By Andrew Brown

When we see a hole made in a tree we look at it and decide or imagine what kind of woodpecker was
responsible and give the matter little further thought. In fact, in my mind it is an interesting ornithological
scenario.
When choosing a nest site a woodpecker has to make a number of important decisions: Firstly, the
pair must decide the general area and precise location in which to build the nest with regard to security,
food availability, flight path, not to intrude into the territory of another bird of the same species etc.
Secondly, they must select a type of tree in which to nest. The tree must have a density which will allow
the male to drill out the nest, so it must be of sufficient circumference to allow the male to drill in a
couple of inches after which there must be room for the chamber. The nest will be built in spring when
the amount of rising sap will be at its greatest which will make drilling more difficult. A soft wood tree is
chosen and in sandy soil where I live sweet chestnut is the most often used species of tree. I have
never seen a nest in an oak tree, for example, probably because the density of the wood is too great.
Next, whichever bird makes the decision which tree to use must decide the direction which the hole will
face, possibly the most crucial decision which has to be made. If you imagine the conditions in the hole
with at least one adult and several young inside a south facing hole could well result in asphyxiation at
the height of summer. For the nest facing west the prevailing wind and rain could be a problem. The
nest I am going to tell you about faces north and is visible from my kitchen window and from my
observations it is the most common but not universal aspect. Lastly, and less importantly, is the height
of the nest which, from my observations of the larger woodpeckers, is more than three metres high
and always in the trunk of a tree. Also important is the aerial route to the hole as busy parents make
their many food delivery flights.
The male Greater Spotted Woodpecker began excavating their hole in late April and was amusing to
watch as he made a hole a millimetre bigger than himself and was often squeezed into that hole using
all his force and energy with his feet flailing in the air to give his thrust extra emphasis as he excavated
the nest. This went on for some days until I heard a great commotion and rushed outside to witness a
bitter fight between a green and yellow bird and a red, black and white one, a bit reminiscent of Norwich

City versus Manchester United. The Canaries were successful and the Green Woodpecker took over
control of the nest. The Green Woodpecker is considerably larger than the Greater Spotted and thus
had to enlarge the entrance hole, again, no more than absolutely necessary. For several days it was in
the same ungainly position as the Greater Spotted as it presumably started to excavate the chamber.
We have to give much credit to both species as it would be very difficult for man with all his tools to
carve out a minimum two inch long entrance hole and then to construct an interior chamber at right
angles maybe four or five inches in diameter and six inches or more deep into sap laden wood. I have
tried to envisage how this would be achieved and really cannot imagine how it could be done.
Remember that all the excavated material has to be removed from the nest through the entrance hole
which is no bigger than the bird.
The Green Woodpeckers successfully raised their young and the hole in the tree became history, except
that it didn’t – despite the fact that woodpeckers don’t seem to use the same hole again.
We are very fortunate to have a few pairs of Nuthatches in the area, and their chirpy calls in winter are
always a welcome sound. In early spring I noticed a pair taking an interest in the hole in the tree and
soon, after much consideration, they decided to use the hole as their nesting site. I was surprised at
this as the holes I had seen them use were much smaller.
The male nuthatch spent nearly a couple of weeks emptying the nest of its contents which included
amongst other things strips of wood which led me to believe that the Green Woodpecker had torn these
from the hole when excavating the nest rather than drilling. It then proceeded to take ages to reduce
the size of the hole with a new front door, presumably made from mud or clay and saliva. They then
successfully raised their young. Ten years later I can still see the hole from my kitchen window.
The above is from my own observation and supposition of what was going on in that hole. There is still
a lot we don’t know for sure about what actually happens inside these woodpeckers’ nests. One
question is foremost in my mind – Green Woodpeckers don’t drill, so how does it build a nest without
usurping the Greater Spotted?

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