This was in the most recent issue of Juournal of Field
Ornithology. I thought it might be useful to those concerned
about nest box parasites.

Dawson, Russell D. 2004. Efficacy of diatomaceous earth at
reducing populations of nest-dwelling ectoparasites in Tree
Swallows. J Field Ornithol. 75(3):232-238


ABSTRACT. Nest-dwelling parasites are known to have detrimental
consequences for many birds, and thus it may be desirable for
management practices to remove these parasites. In addition,
manipulation of parasite loads is often necessary for studying
host-parasite evolution. While there are various methods that are
effective at reducing parasite loads in nests, many of them
have shortcomings because they require specialized equipment,
are time consuming, or involve toxic substances that may be
dangerous to both birds and researchers. I evaluated the efficacy
of simple-to-use, non-toxic diatomaceous earth (DE) at reducing
ectoparasite loads in nests of Tree Swallows (Tachycineta bicolor)
over two field seasons. Diatomaceous earth significantly reduced
population sizes of bird fleas (Ceratophyllus idioms) and various
species of blow flies (Protocalliphora spp.) in both years.
Diatomaceous earth appeared to be more effective at reducing
the numbers of fleas, possibly because fleas have smaller body
size and so are more easily desiccated by the abrasive action of
DE. Although DE was effective against both fleas and blow
flies, it did not completely rid nests of either type of parasite.

--
Mike Patterson
Astoria, OR
celata at pacifier.com