The Canadian Field-Naturalist (E-Journal)
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"Islands of Grass" by Trevor Herriot, photography by Branimir Gjetvaj, 2017. [book review]
No full textDiet of Grey Wolves (Canis lupus) During Calving in a Moose– Caribou System in Northern Ontario
Get PDFGrey Wolves (Canis lupus) are a leading proximate cause of declining populations of Woodland Caribou (Rangifer tarandus), a threatened species. Although predation on adult caribou has been well documented, less is known about predation on neonatal calves. We used scat analysis to examine the diet of wolves in an area of Ontario overlapping the receding southern limit of caribou occurrence. Wolves consumed mostly Moose (Alces americanus; 82.7%), followed by American Beaver (Castor canadensis; 10.9%), caribou (3.1%), and Snowshoe Hare (Lepus americanus; 1.5%). This low use of caribou is consistent with other evidence suggesting that caribou are a minor dietary component of wolves in this system; however, because most caribou consumption consists of calves, the impact on this slowly reproducing species may still be significant
Factors affecting litter size in Western Gartersnake (Thamnophis elegans) in British Columbia: place, time, and size of mother
Get PDFLife-history traits of organisms are influenced by both genetic and environmental factors. We used counts of offspring in captive-born litters to determine how geographic location, year-to-year variation, and body size of mother affected litter size of Western Gartersnake (Thamnophis elegans) in four widely separated populations in British Columbia. Litter size varied significantly among populations, but that variation was largely explained by differences in maternal body size among populations; that is, larger females had larger litters. With maternal size treated as a covariate, there was no further significant effect of location or of different years within sites on litter size. The overall regression, pooled over sites and years, between litter size and size of mother accounted for 55% of the total variation in litter size. Nonetheless, the significant variation in body size among locations calls for explanation and the consequent differences in litter size could be important demographically. Presumably, the large amount of unexplained residual variation reflects other differences, beyond body size, between individual mothers. Such differences among individuals might be determined by genetics or by environmental effects such as foraging success, but our data cannot address this question
"Insects: Their Natural History and Diversity: With a Photographic Guide to Insects of Eastern North America, Second Edition, Revised and Updated" by Stephen A. Marshall, 2017. [book review]
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"The Wolf: A True Story of Survival and Obsession in the West" by Nate Blakeslee, 2017. [book review]
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Sora (Porzana carolina) Parasitism of Red-winged Blackbird (Agelaius phoeniceus) Nests
Get PDFSora (Porzana carolina) is a conspecific brood parasite that also occasionally parasitizes nests of other species. Sora parasitism in nests of passerines is rare. Of 129 Red-winged Blackbird (Agelaius phoeniceus) nests found in North Dakota in 2009 and 2010, two (1.6%) were parasitized by Soras. The conditions favouring this rare parasitic behaviour may include competition for nest sites and high Sora density