This is a dark brown spider with a pale oval ring marking on its abdomen which has a dark 'cardiac' mark in its centre. It often has orange/brown chevrons below this cardiac mark.
It is very similar to A. similis and the two cannot reliably be distinguished by eye however they can often be identified from the habitat. If in a garden or associated with houses then it is almost certainly A. similis, however if in woodland it is highly likely to be A. fenestralis.
Found under bark and stones, in crevices in masonry, often around windows and sills, hence its name.
Predatory on many other invertebrates, including other spiders. Its web is characteristically very pale blue-grey or white, and the strands are 'fluffed' by the spider to tangle the feet of its insect prey. The web usually forms an open funnel leading to the spider's retreat in the deepest part of the crevice. The spider can be attracted from its lair by holding a sounding tuning fork against its web, presumably resembling the sound of a trapped insect.
Common and widespread in Britain.
Common in Leicestershire and Rutland.
5,115 British records for this species to 2015.
Leicestershire & Rutland Map
Enter a town or village to see local records
Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015