Infestation parameters for chewing lice (Phthiraptera: Amblycera, Ischnocera) parasitising true thrushes (Aves: Passeriformes: Turdidae) in Manitoba, Canada

Seven species of Turdidae (Aves: Passeriformes) in Manitoba, Canada were examined for chewing lice (Phthiraptera) in 1993–2019: Turdus migratorius (N = 570), Catharus ustulatus (N = 135), Catharus guttatus (N = 49), Catharus minimus (N = 12), Catharus fuscescens (N = 1), Sialia sialis (N = 4), and Sialia currucoides (N = 3). Five species of lice on T. migratorius had a prevalence of 24.0% and a mean intensity of 16.7. Overall prevalence for lice on C. ustulatus, C. guttatus, and C. minimus was 25.0%–59.2%; mean intensity was 7.0–23.3. On S. sialis, the prevalence was 50.0%; mean intensity was 10.0. No lice infested C. fuscescens or S. currucoides. Infestation parameters for each louse–host combination are provided. Louse infestations were highly aggregated. Female lice were more prevalent than males, especially for Ricinus elongatus (Phthiraptera: Amblycera: Ricinidae) infesting T. migratorius (eight males; 81 females), or there was no significant deviation from 50:50. Infestation parameters were higher for adult T. migratorius than for juveniles or feathered chicks but not significantly so. Mean intensity was greater in spring than in fall. Louse abundance was lower than on hosts of similar size in Manitoba and lower than on thrushes in other studies.