This checklist includes taxa of chewing lice from published records, old collections, and recently collected material from birds and mammals in Slovakia. Data from established collections correspond to five different periods: (1) 1925–1939, collection of Karel Pfleger; (2) 1946–1978, collection of František Balát; (3) 1974–1985, collection of Vladimír Straka; (4) 1997–2012, collection of Ján Krištofík; and (5) 2008–2019, a collection made by the authors of this paper. A total of 255 species of feather lice—67 amblyceran species in 22 genera of families Laemobothriidae, Menoponidae and Ricinidae, and 188 ischnoceran species in 54 genera of the family Philopteridae—and 366 host-louse associations are listed from 171 bird species in 21 orders. In addition, eight species of chewing lice in five genera of the family Trichodectidae are listed from eight species of mammals. Species of chewing lice are reported from about 240 different locations throughout the territory of Slovakia. Also, 43 species of lice and 20 host-louse associations for Slovakia, as well as four host-louse associations for the world, are included as new records. A host-louse list of recorded species is also given.

A total of 1185 passerine birds representing five species were examined for chewing lice in reed beds in southwestern Slovakia in spring (April) 2008, 2009 and 2016. Additional collecting focused only on chewing lice from Panurus biarmicus (Linnaeus, 1758) (Passeriformes: Panuridae) was carried out in spring (April), summer (July) and autumn (October) 2019. A total of 283 (24%) birds were parasitized by 10 species of chewing lice of four genera: Penenirmus, Menacanthus, Philopterus, and Brueelia. Most birds showed only very light (1–10 lice/host; 74%) to light infestations (11–20 lice/host; 16%). The authors found significantly higher prevalences and mean abundances of chewing lice on residents/short‐distance migrants, that is, P. biarmicus, Acrocephalus melanopogon (Temminck, 1823) (Passeriformes: Acrocephalidae), than on long‐distance migratory birds, that is, Acrocephalus scirpaceus (Hermann, 1804), Acrocephalus schoenobaenus (Linnaeus, 1758) (Passeriformes: Acrocephalidae), Locustella luscinioides (Savi, 1824) (Passeriformes: Locustellidae). No significant difference was found in the total mean intensity of chewing lice between these two groups of birds. Ischnoceran lice were more prevalent and abundant than amblyceran lice on residents and short‐distance migrants, whereas the opposite was found on bird species that migrate long distances. A total of 146 (58%, n = 251) P. biarmicus were parasitized by 1490 chewing lice. Males of P. biarmicus showed higher prevalence and mean abundance than females with gradually descending values of prevalence, mean abundance and mean intensity from spring to autumn. The knowledge of the occurrence and population dynamics of lice on wild passerine birds can be useful in endangered species conservation programs and can also be applied to captive passerine birds, which may be analogous to resident birds in this sense.

Thirteen species of chewing lice in theBrueelia-complex are redescribed and illustrated. They are:BrueeliablagovescenskyiBalát, 1955, exEmberizaschoeniclus(Linnaeus, 1758);B.breueriBalát, 1955, exChlorischloris(Linnaeus, 1758);B.conocephala(Blagoveshchensky, 1940) exSittaeuropaea(Linnaeus, 1758);B.ferianciBalát, 1955, exAnthustrivialis(Linnaeus, 1758);B.gliziBalát, 1955, exFringillamontifringillaLinnaeus, 1758;B.kluziBalát, 1955, exFringillacoelebsLinnaeus, 1758;B.kratochviliBalát, 1958, exMotacillaflavaLinnaeus, 1758;B.matvejeviBalát, 1981, exTurdusviscivorusLinnaeus, 1758;B.pelikaniBalát, 1958, exEmberizamelanocephalaScopoli, 1769;B.rosickyiBalát, 1955, exSylvianisoria(Bechstein, 1792);B.vanekiBalát, 1981, exAcrocephalusschoenobaenus(Linnaeus, 1758);Guimaraesiellahaftorni(Balát, 1958) exTurdusiliacusLinnaeus, 1758;G.lais(Giebel, 1874) exLusciniamegarhynchos(Brehm, 1831). Redescriptions are made from type material where available. Holotypes are identified in Balát’s material when possible, and lectotypes are designated forB.blagovescenskyi,B.breueri,B.glizi,B.ferianci,B.kluzi,B.kratochvili,B.pelikani, andB.rosickyi; a neotype ofNirmuslaisGiebel, 1874 is designated.BrueeliaweberiBalát, 1982, is placed as a synonym ofBrueeliaconocephala(Blagoveshchensky, 1940).

Four new species of Brueelia Kéler, 1936 are described and illustrated. All of them parasitize African endemic host species in the families Passeridae, Ploceidae, and Estrildidae (Passeriformes). They are: Brueelia pofadderensis sp. nov. ex Passer melanurus damarensis Reichenow, 1902 and P. m. vicinus Clancey, 1958; B. semiscalaris sp. nov. ex Granatina granatina (Linnaeus, 1758); B. sima sp. nov. ex Malimbus nitens (Gray, 1831); B. terpsichore sp. nov. ex Euplectes jacksoni (Sharpe, 1891) and E. progne delamerei (Shelley, 1903). In addition, Brueelia bicurvata (Piaget, 1880) is redescribed and reillustrated from non-type material. A summary of all published records of lice in the Brueelia complex from Africa since 1980 is provided. We also estimate the unknown diversity of African species of Brueelia based on an index of host specificity calculated for each host family independently. The unknown diversity is estimated to be over 1000 species of Brueelia from African hosts, compared to the < 50 species in this genus currently recorded from Africa.

A total of 266 wild passerine birds (Passeriformes) representing eight species and nine subspecies from three islands of the Archipelago of the Azores were examined for ectoparasites. Two species of louse-flies Ornithomya avicularia and Ornithoica turdi (Diptera: Hippoboscidae), three species of fleas Ceratophyllus gallinae, Ceratophyllus sp. and Dasypsyllus gallinulae (Siphonaptera: Ceratophyllidae), and 11 species of chewing lice belonging to the genera Menacanthus, Myrsidea (Phthiraptera: Menoponidae), Ricinus (Phthiraptera: Ricinidae), Brueelia, Guimaraesiella, Philopterus, Sturnidoecus and Turdinirmus (Phthiraptera: Philopteridae) were recorded. At least one species of ectoparasite was found on 114 birds of six species. Guimaraesiella tovornikae and Myrsidea sylviae from Sylvia atricapilla are redescribed. Records of Ceratophyllus sp. and Sturnidoecus sp. from Turdus merula represent new parasite-host associations. Phoresy of Guimaraesiella amsel on Ornithoica turdi was also found. Parasitological parameters such as prevalence, intensity and abundance and geographic distribution of recorded ectoparasites are provided.