On the Atlantic island of Madeira, mobile invertebrate predators such as perlid and perlodid stoneflies as well as a native fish fauna are absent, permitting tests of hypotheses concerning the influence of predators on the nocturnality of drift. Here, species and size composition of the drift, in addition to drift lengths, were studied in two man‐made waterways (levadas). It was found that the following insects dominated in the drift:Baetis rhodani(Ephemeroptera),Dixa tetrica(Diptera), Chironomidae (Diptera), and Simuliidae (Diptera). Wind increased the drift density, evidently by causing large amounts of terrestrial plant material to enter, especially in the more open streams. It seems likely that the drifting material caused the benthic animals to drift either through direct mechanical action or via indirect effects, such as visual disturbance.