David A. Boag

Litter Size in Columbian Ground Squirrels (Spermophilus columbianus)

Measures of litter size, based on counts of corpora lutea, placental scars, embryos, and juveniles emerging from natal burrows, were determined from 181 Columbian ground squirrels ( Spermophilus columbianus ) collected in three areas in southwestern Alberta, Canada, and from observations of 88 litters that emerged in these areas. Most measures of litter size differed between areas and were lower at a high elevation site (2,170 m) than at the other two sites (elevation 1,500 m). We suggest that differences between areas may be related to timing of snow melt and onset of vegetative growth. Columbian ground squirrels have smaller litters than most other North American species of ground squirrel, perhaps reflecting different life history tactics.

Fate of carbofuran and its effects on aquatic macroinvertebrates in Canadian prairie parkland ponds

A multipond study was conducted in 1986 to determine the fate of carbofuran and its effects on aquatic macroinvertebrates in alkaline, Canadian prairie parkland ponds. Four ponds were sprayed with carbofuran in late July; four other ponds served as controls. Sixteen hours after spraying, concentrations of carbofuran in the water column ranged from 9–32 μg l−1. After 124 h, concentrations had declined to 3–12μg l−1. Carbofuran partitioned into submersed aquatic plants, ranging from three to 46 times greater in the plants than in the surrounding water. Carbofuran was below detection limits in most sediment samples. Among the aquatic macroinvertebrates considered in this study, the crustacean Hyalella azteca and trichopteran larvae declined significantly in abundance following the application of carbofuran. Coenagrionidae and small chironomid larvae did not decline following carbofuran application. Hyalella azteca abundance remained relatively low in treatment ponds through to May 1987, while trichopteran larval abundance had recovered by August 1986. There were no readily apparent shifts in community structure in this study, although slight, disproportionate increases in Chironominae and Coenagrionidae in the treatment ponds following spraying may have resulted from such factors as reduced competition or a change in the size or composition of the food base.

The Autumn Diet of Spruce Grouse: A Regional Comparison

Spruce Grouse (Canachites canadensis) are distributed across much of northern North America (Aldrich 1963 ) . In recent years several workers have reported on the autumn or year-round food habits of this species in widely separated regions of the continent (Crichton 1963, in Ontario; Jonkel and Greer 1963, in Montana; Ellison 1966, in Alaska; Pendergast and Boag 1970, in Alberta). During September and early October of 1957 through 1961, we collected 113 crops from Franklin’ s Spruce Grouse (C. c. franklinii) in north-central Washington. In this note, we compare quantitative and qualitative characteristics of the contents of these crops to similar data for Spruce Grouse from other regions, and to similar data for Blue Grouse (Dendrugapus o&urns) in the same region from which our samples were collected. All crops were taken from birds shot by hunters. Samples were collected at a checking station near the boundary of a 100 square mile study area in the Conconully region of north-central Washington (see Zwickel et al. 1966). Crop contents were preserved in formalin and analyzed wet.