There are no animals which actually feed on bricks, mortar or plaster, but there are many, such as woodlice, earwigs and spiders, which use the holes and cracks that appear in masonry as places to hide in or for laying their eggs. There are, however, some which actually dig their way into mortar.
Woodpeckers
Now and again woodpeckers find out that there are fat, juicy bee larvae in the wall. Once they have learned the trick they will arrive and hack great craters in the mortar in order to get at the grubs. If one cannot tolerate this form of biological control it will be necessary to scrape out the larvae and make good the mortar.
Sparrows
Sparrows and tits often climb around walls searching for insects and spiders which they pull out of holes and crevices. Normally they do no damage to the wall, but sparrows and pigeons may peck lime out of the mortar and in some cases damage the bricks.
Larvae of Dermestid beetles
The larvae of dermestid beetles frequently gnaw their way into a variety of materials when they are about to pupate. It is rare for them to bore into plaster but they occasionally do so.
Mice and rats
Glass wool used for insulation might not appear to be a very suitable material for nests but in spite of this, mice and rats will gnaw tunnels through it and construct their nests in it, thus reducing its effectiveness as an insulator.
Bumpble bees
Bumble bees may also establish them- selves in insulating material, but the damage done will be local and not very serious.
When tufts of insulating material appear under the eaves it will normally be due to sparrows or starlings that have pulled it out to make a place for their nests.
"Pests in House and Home"
"Bed Bugs - Bites, Stings and Itches"
"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
"Skadedyr i træ" (Timber Pests - Only danish)
"Stuefluen" (Common Housefly - Only danish)