Feather mites of the subfamily Pterodectinae (Acariformes: Proctophyllodidae) from passerines and kingfishers in Canada

Investigation of the diversity and taxonomy of feather mites of the subfamily Pterodectinae (Astigmata: Proctophyllodidae) on passerines (Passeriformes) and kingfishers (Coraciiformes: Alcedinidae) in Manitoba revealed 19 species in 5 genera. Of them, eight new species are described, seven of these from passerines and one from a kingfisher: Alaudicola eremophila sp. n. from Eremophila alpestris (Alaudidae), Amerodectes icteri sp. n. from Icterus galbula (Icteridae), A. pheucticus sp. n. from Pheucticus ludovicianus (Cardinalidae), A. tiffanyluiae sp. n. from Oporornis agilis (Parulidae), A. tretiakae sp. n. from Molothrus ater (Icteridae), Tyrannidectes sealyi sp. n. from Tyrannus tyrannus (Linnaeus, 1758) (type host) and Tyrannus verticalis Say, and T. empidonicus sp. n. from Empidonax minimus (Tyrannidae), and Proterothrix megaceryle sp. n. from Megaceryle alcyon (Alcedinidae). Additionally, nine pterodectine species are reported for the first time in the fauna of Canada. Based on re-evaluation of diagnostic charcters, new diagnoses are proposed for the genera Amerodectes, Tyrannidectes, and Metapterodectes, and species contents of these genera are revised. Four species are transferred from the genus Amerodectes to Tyrannidectes with the new combinations proposed: T. caribaeus (Mironov and González-Acuña, 2011) comb. n., T. charitomenos (Hernandes, 2018) comb. n., T. pitangi (Mironov, 2008) comb. n., T. vireonis (Hernandes and Pedroso, 2016) comb. n. Six species are transferred from the genus Tyrannidectes to Metapterodectes with the new combinations: M. amaurochalinus (Hernandes and Valim, 2006) comb. n., M. cinclodes (Mironov and González-Acuña, 2011) comb. n., M. crassus (Trouessart, 1885) comb. n., M. falcklandicus (Mironov and González-Acuña, 2011) comb. n., M. fissuratus (Hernandes and Valim, 2005) comb. n., and M. pteroptochi (Mironov and González-Acuña, 2015) comb. n.

Temporal trends in bird abundance in response to thinning of lodgepole pine (Pinus contorta)

Forest managers are continually seeking methods of extracting more timber from the land base while maintaining appropriate wildlife habitat. A 7-year before–after control–impact (BACI) experiment was conducted in 60-year-old lodgepole pine (Pinus contorta Douglas ex Loudon) to determine the effects of thinning on forest birds. One year of pretreatment data was compared with 6 years of posttreatment data. Using linear trend analysis corrected for detection error, we found that Chipping Sparrow (Spizella passerina (Bechstein, 1798)), Dark-eyed Junco (Junco hyemalis (Linnaeus, 1758)), and Red-eyed Vireo (Vireo olivaceus (Linnaeus, 1766)) increased over time in thinned stands and declined in control stands. Alder Flycatcher (Empidonax alnorum Brewster, 1895), Hermit Thrush (Catharus guttatus (Pallas, 1811)), Rose-breasted Grosbeak (Pheucticus ludovicianus (Linnaeus, 1766)), and Blue-headed Vireo (Vireo solitarius (Wilson, 1810)) decreased in control and thinned stands but declined more in controls. Varied Thrush (Ixoreus naevius (J. F. Gemlin, 1789)) and White-winged Crossbill (Loxia leucoptera Gemlin, 1789) increased in control stands relative to thinned areas, where they were stable or declined. A significant interaction between treatment and year was observed for 24 species when year was categorical. Of these, species more likely found in control stands were Boreal Chickadee (Poecile hudsonicus (J.R. Forster, 1772)), Golden-crowned Kinglet (Regulus satrapa Lichtenstein, 1823), and Least Flycatcher (Empidonax minimus (W.M. Baird & S.F. Baird, 1843)), whereas Ruffed Grouse (Bonasa umbellus (Linnaeus, 1766)), Tennessee Warbler (Vermivora peregrina (A. Wilson, 1811)), and Warbling Vireo (Vireo gilvus (Vieillot, 1808)) were more likely in thinned stands. Total bird abundance was higher in thinned stands, which is consistent with 83% of thinning studies in western coniferous forests. Thinning can be a useful tool for achieving wildlife management goals and increasing timber yields.

Using stable isotopes to track frugivory in migratory passerines

Several species of North American migratory songbirds undergo seasonal diet shifts from insects to fruits, but this phenomenon is poorly quantified. Measurement of naturally occurring stable isotopes of carbon (δ13C) and nitrogen (δ15N) are linked to sources of diets and trophic level, respectively. We used stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of blood and claw tissues of 16 species of migratory songbirds to evaluate the timing and extent of frugivory over different periods. Species differed considerably in their tissue δ15N values, but we found poor isotopic segregation of species according to our a priori classifications as insectivores or omnivores. Season accounted for considerable variance in tissue δ15N values. However, only American Robin ( Turdus migratorius L., 1766), Northern Oriole ( Icterus galbula (L., 1758)), Gray Catbird ( Dumetella carolinensis (L., 1766)), Least Flycatcher ( Empidonax minimus (W.M. Baird and S.F. Baird, 1843)), and Warbling Vireo ( Vireo gilvus (Vieillot, 1808)) showed expected decrease in winter-grown tissue δ15N values compared with those grown in late summer. This indicates either that our a priori guild associations were incorrect and (or) that using stable isotopes to track frugivory at continental scales is problematic. We recommend that the isotope technique be used to track frugivory only in well-constrained systems where food-web δ15N follows reliable and understood trophic enrichment patterns.