at 1 (noting the ubiquity of the Dark-eyed Juncos
Northern cardinals, dark-eyed juncos
, and song sparrows were collected on the study areas during November, December, January, and February of 1980-81, 1981-82, and 1982-83; white-throated sparrows were collected in 1982-83 only.
I conducted song playbacks on the territories of 30 male Dark-eyed Juncos
(Junco hyemalis) located at Mountain Lake Biological Station and the grounds of Mountain Lake Hotel in Pembroke, Virginia, USA (37[degrees]22'N, 80[degrees]32'W).
Seasonal and individual variation in response to GnRH challenge in male Dark-eyed Juncos
Tail length is also of interest in studying morphological variation in Dark-eyed Juncos
8 cm apart, and all 21 (95%) other fatalities at the clear glass control that included: one Mourning Dove (Zenaida macroura), one Black-capped Chickadee, three Northern Cardinals, one Purple Finch (Carpodacus purpureus), one White-throated Sparrow (Zonotrichia albicollis), and 14 Dark-eyed Juncos
([chi square] = 58.
Vegetation on the study site was largely mixed deciduous and coniferous forest that supports an abundant population of Dark-eyed Juncos
breeding at 2,000 m in Jasper National Park, Alberta had a 59% reduction in seasonal duration of clutch initiation compared to juncos at 1,000 m in the same area (40 vs.
hyemalis dorsalis) frequently consist of two or three trills, or a trill with one or two buzzy notes (Thatcher 1968, Sibley 2000, Christian Nunes recordings), and are apparently intermediate in complexity between the songs of other Dark-eyed Juncos
and those of J.
For example, artificially elevating testosterone in female Dark-eyed Juncos
(Junco hyemalis) resulted in delayed onset of egg laying after nest completion as well as lower body mass and delayed molt (Clotfelter et al.
The most abundant species were Yellow-rumped Warblers and Dark-eyed Juncos
(Junco hyemalis), which together accounted for 41% of the migrant passerine populations estimated.
Five Dark-eyed Juncos
(Junco hyemalis), one White-throated Sparrow (Zonotrichia albicollis), and one House Sparrow (Passer domesticus) were captured in March for use as subjects, housed in small cages, and tested from mid-March and throughout April.