Seasonal population dynamics of chewing lice (Phthiraptera: Amblycera and Ischnocera) infesting three species of woodpeckers (Aves: Piciformes: Picidae) in Manitoba, Canada

Three species of woodpeckers (Piciformes: Picidae) in Manitoba, Canada, were examined for chewing lice (Phthiraptera): the resident downy woodpecker (Picoides pubescens (Linnaeus), n = 55), and two migrants, yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n = 316) and northern flicker (Colaptes auratus (Linnaeus), n = 225). Six species were collected: Menacanthus pici (Denny) (Amblycera: Menoponidae) from all hosts, and five species of Ischnocera (Philopteridae): Penenirmus auritus (Scopoli) from downy woodpeckers and sapsuckers, Picicola snodgrassi (Kellogg) and Brueelia straminea (Denny) from downy woodpeckers, and Penenirmus jungens (Kellogg) and Picicola porisma Dalgleish from flickers. Adults and nymphs were present on downy woodpeckers all year, and on migrant sapsuckers and flickers from when they arrived until they left, suggesting lice reproduce continuously on their hosts. Prevalence and mean intensities of louse infestations generally decreased from their respective springtime levels to their lowest values during or at the end of the breeding season of their hosts, and then increased in various degrees during the fall. No seasonal pattern in louse sex ratios was observed except on northern flickers, where male to female ratios for two of three species were lowest during the breeding season. Resident and migrant hosts had similar seasonal patterns of infestation by lice.