The Canadian Field-Naturalist (E-Journal)
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"The Environment: A History of the Idea" by Paul Warde, Libby Robin, and Sverker Sörlin, 2018. [book review]
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"The Birds of Nunavut, Volume 1: Nonpasserines, Volume 2: Passerines" by James M. Richards and Anthony J. Gaston, 2018. [book review]
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"The Uninhabitable Earth: Life After Warming" by David Wallace-Wells, 2019. [book review]
No full textNew avian breeding records for Kugluktuk, Nunavut
Get PDFNew breeding records for 10 species of tundra and boreal nesting birds were documented near the community of Kugluktuk (Nunavut, Canada) over the course of the 2015 and 2016 breeding seasons and incidentally in 2017 and 2018. These species include American Wigeon (Mareca americana), Mallard (Anas platyrhynchos), Northern Shoveler (Anas clypeata), Green-winged Teal (Anas carolinensis), Greater Scaup (Aythya marila), Say’s Phoebe (Sayornis saya), Canada Jay (Perisoreus canadensis), Greycheeked Thrush (Catharus minimus), Yellow-rumped Warbler (Setophaga coronata), and Dark-eyed Junco (Junco hyemalis). Previously unpublished breeding evidence for Bald Eagle (Haliaeetus leucocephalus) is also discussed along with suspected breeding of Barn Swallow (Hirundo rustica), Bohemian Waxwing (Bombycilla garrulus), White-throated Sparrow (Zonotrichia albicollis), and Pine Grosbeak (Pinicola enucleator). These records represent the first described breeding occurrences for these species in the Kitikmeot region, or new records for the mainland of Nunavut. A lack of historical ornithological survey effort in this area has likely led to the diversity of these previously unrecorded breeding observations. These results highlight the need to increase geographic coverage of bird surveys in northern Canada to more accurately delineate the northern limit of breeding ranges and suggest that further formal survey effort will undoubtedly lead to additional new breeding records
Divorce in Canada Geese (Branta canadensis): frequency, causes, and consequences
Get PDFMost Canada Geese (Branta canadensis) form lifelong pair bonds (same-mate geese), but some pairs break apart and the geese mate with new partners while their former mates are still alive (divorcees). Over 25 years, we assessed lifelong reproduction of 160 collared Canada Geese that nested for multiple years in New Haven County, Connecticut. We examined whether same-mate geese and divorcee geese differed from each other prior to or after the divorce. Fifteen percent of females and 18% of males divorced during their lifetimes. Divorces were more frequent in pairs that produced fewer hatchlings during their prior nesting year. Most divorcees that nested again did so on their former nesting territories. Replacement partners of divorcees averaged younger and had fewer years of nesting experience than the divorcees’ prior mate. Usually after a divorce, one divorcee of each former pair nested immediately while the other skipped one or more years before nesting again. Under such circumstances, the partner able to nest immediately can increase its direct fitness by finding a new partner and nesting rather than foregoing the opportunity to nest that year. During their first nesting year after the divorce, the reproductive success of divorcees and same-mate geese were similar
A Canadian range extension for Wormslug (Boettgerilla pallens; Gastropoda: Stylommatophora: Boettgerillidae)
Get PDFThe introduced Wormslug (Boettgerilla pallens Simroth, 1912) is reported from Quebec, Canada, for the first time, from two closely situated localities in Gatineau Park. It was previously reported from the Vancouver area of British Columbia and, very recently, from Newfoundland. Within the Americas, the species has been reported from northern California, Mexico, and Colombia, and, because it is easily overlooked, likely occurs elsewhere in North America, especially in the eastern United States. In Quebec, it was found in a natural Sugar Maple (Acer saccharum Marshall) woodland and an ornamental garden. Wormslug likely reached both sites with shrub plantings from commercial nurseries, probably quite recently, because the invasive spread of the species, worldwide, has occurred mostly during the last few decades. Although the woodland where it occurred is dominated by native plants, the gastropod fauna there is mainly introduced. Identification, characteristics, and ecology of Wormslug are discussed. The potential for impact on native soil and soil surface organisms, including native terrestrial slugs and snails, is noted
Seasonal and temporal variation in scaled mass index of Black-capped Chickadees (Poecile atricapillus)
Get PDFAvian body mass reflects a trade-off between risk of starvation and predation, and may vary with ambient temperature, age, and time of day. Seasonal variability in body mass is a common occurrence in northern temperate regions, including adaptive fattening. Previous evidence suggests that seasonal variability is less pronounced in tree-feeding bird species, as their food sources during winter are less limited and variable compared to ground-foraging species. We determined fat scores of tree-feeding Black-capped Chickadees (Poecile atricapillus) captured year-round between 2004 and 2015 (n = 4248) in southern Quebec, to test the relative strength of possible drivers of variability in chickadee body mass, including time, date, and year of capture, age, and temperature. First, we demonstrated that scaled mass index (SMI) was the body condition index, out of four possible indices tested, which most strongly correlated with fat scores measured in the field. We used SMI subsequently as our estimator of body condition to avoid observer effects associated with fat scores. Similar to other studies, time of capture significantly affected SMI, in which birds captured later were heavier, indicating that chickadees experience overnight weight loss and subsequent weight gain from foraging throughout the day. SMI was constant from April to November, then peaked in late winter, but was not influenced by daily temperature after accounting for month and year. SMI was not significantly affected by age. We concluded that adaptive fattening is an evolutionary response to risk of starvation in winter, rather than a proximal response to immediate ambient temperature