Do Female Songbirds Avoid a Mammalian Nest Predator When Selecting Their Nest Site?

Perceived predation risk can elicit strong behavioral responses in potential prey. During nest building, songbirds exhibit anti-predator behaviors under experimental conditions. Here, we hypothesized that females of two ground-nesting songbird species, the Ovenbird (Seiurus aurocapilla) and the Hermit Thrush (Catharus guttatus), would use naturally available cues of predation risk when selecting their nest site, thereby avoiding activity hotspots of Eastern Chipmunks (Tamias striatus), a predator on songbird nests and fledglings. Chipmunks are highly vocal, thus providing cues of their presence. We mapped chipmunk detections and songbird nests over four successive years in study plots located in mature deciduous forest of New Brunswick, Canada. Chipmunk activity varied by an order of magnitude among study plots and years. Nests were built further away from chipmunk detections than expected by chance in some, but not all, plot-year combinations. When comparing study plots, the proportion of nests built within hotspots of chipmunk activity was four times lower in the two plots where chipmunk activity was highest. Yet, we did not find clear evidence that chipmunk avoidance provided fitness benefits, possibly because this behavior procured little protection at high chipmunk densities. The persistence of this avoidance behavior in our focal species of ground-nesting songbirds might be linked to the benefits it procures at intermediate chipmunk densities.

Feather mites of the genus Trouessartia (Acariformes: Trouessartiidae) from passerines (Aves: Passeriformes) in Georgia, USA

Ten new species of the feather mite genus Trouessartia Canestrini, 1899 (Analgoidea: Trouessartiidae) are described from various passerines of the superfamily Passeroidea in Georgia: Trouessartia americana sp. n. from Setophaga americana (Linnaeus), T. helmitheros sp. n. from Helmitheros vermivorum (Gmelin, JF), T. mniotilta sp. n. from Mniotilta varia (Linnaeus), T. pensylvanica sp. n. from Setophaga pensylvanica (Linnaeus) (type host) and S. palmarum (Gmelin, JF), T. ruticilla sp. n. from S. ruticilla (Linnaeus), T. seiurus sp. n. from Seiurus aurocapilla (Linnaeus), T. tigrina sp. n. from Setophaga tigrina (Gmelin, JF) (Parulidae), T. passerinae sp. n. from Passerina caerulea (Linnaeus) (type host) and P. cyanea (Linnaeus), T. ciris sp. n. from P. ciris (Linnaeus) (Cardinalidae), and T. spizellae sp. n. from Spizella passerina (Bechstein) (Passerellidae). Based on a specific combination of morphological characters, all new species and six previously known species are arranged into a new species group capensis in the genus Trouessartia. The most important diagnostic characters of this species group include: in both sexes, the dorsal hysterosomal apertures are absent; in males, the postgenital plaque is well developed and genital setae g have cylindrical articulation rings; in females, the external copulatory tube is straight, stylet- or finger-like, and situated on the margin of the interlobar membrane, and the head of spermatheca has a semi-ovate extension without indentations. A key to all species referred to the capensis group is provided and host associations of this group with passerines are summarized and briefly discussed. It is hypothesized that this species group originated on the ancestors of New World nine-primaried oscines (Emberizoidea) and diverged in close relation with this group of hosts.

New feather mites of the genus Amerodectes Valim and Hernandes (Acariformes: Proctophyllodidae) from passerines (Aves: Passeriformes) in Georgia, USA

Eight new species of the feather mite genus Amerodectes Valim and Hernandes, 2010 (Proctophyllodidae: Pterodectinae) are described from passerines (Aves: Passeriformes) in Georgia, USA: Amerodectes cathari sp. n. from Catharus ustulatus (Nuttall) (Turdidae), A. haemorhous sp. n. from Haemorhous mexicanus (Muller, PLS) (Fringillidae), A. helmitheros sp. n. from Helmitheros vermivorum (Gmelin) (Parulidae), A. hribari sp. n. from Geothlypis trichas (Linnaeus) (Parulidae), A. hylocichlae sp. n. from Hylocichla mustelina (Gmelin) (Turdidae), A. passerinae sp. n. from Passerina ciris (Linnaeus) (Cardinalidae), A. seiurus sp. n. from Seiurus aurocapilla (Linnaeus) (Parulidae), and A. spizellae sp. n. from Spizella passerina (Bechstein) (Emberizidae). An updated world checklist of Amerodectes species and a key to species recorded and potentially expected in North America (USA and Canada) are proposed.