Shielding a Bird Box from the sun?

[mcreedy]

We've been feeding the local birds for a while now and decided to buy a bird box at the weekend. I fixed the box to our fence at the back of the garden not far from a 3 foot shrub.

20 mins after putting the box up a pair of blue tits have been checking it out, They've been in and out the box several times and have fought off 2 other blue tits and a finch. Then it dawned on me the box will be in direct sunlight in the afternoon for at least 4 hours.

Does anyone have any suggestions on what could be used to shield a blue tit bird box from direct sun light?

Would hate to take it down but there is no where else in the garden in can go.

[nightshade]

Extend the sides and top with some thick timber or other natural form of insulation to shade and keep it cooler