Abstract Permanent ectoparasites, adapted to living on their hosts, face limited survival abilities and food availability off the host body. We investigated the variance in survivability and the diet type preferences between bird lice from two different groups — Amblycera and Ischnocera. While phylogenetic or morphological data can easily separate these groups, the difference in their life history characteristics is poorly understood. We observed that ischnoceran lice showed significantly longer survival than amblyceran lice ( p < 0.05) off the host body and experimental supplementing with host feathers further increased the survival time of ischnoceran lice. To examine the preference and possible effects of the diet, we evaluated the presence of feathers, blood or both in 4587 chewing lice (1418 amblyceran and 3169 ischnoceran lice). Blood was found in 36% of amblyceran lice from 14 genera, and no blood was found in ischnoceran lice, pointing to different feeding habits between these two groups. Haematophagy is recorded here for the first time for the genera Ardeiphilus , Gruimenopon, Kurodaia , Machaerilaemus and Meromenopon. Furthermore, we evaluated hypopharynx reduction as a potential predisposition for blood‐feeding in bird lice. Amblyceran lice may be more sensitive to changes in microhabitat conditions than ischnoceran lice, and in some cases, many species of Amblycera may also require an additional dietary source beyond bird feathers for their survival.