The Canadian Field-Naturalist (E-Journal)
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First record of Commander Skate (Bathyraja lindbergi) in Canadian Pacific waters
Get PDFWe report the first verified record of a Commander Skate (Bathyraja lindbergi Ishiyama and Ishihara, 1977) from British Columbia, Canada. A female measuring 829 mm in total length was captured by bottom trawl on 2 August 2009 in Queen Charlotte Sound, Canada (51°37'N, 130°6'W). The depth of capture was 449 m. We used physical characteristics as well as meristic and morphometric characters to identify the specimen as a Commander Skate
New records for Eastern Mosquito Fern (Azolla cristata, Salviniaceae) in Canada
Get PDFWe report a cluster of Eastern Mosquito Fern (Azolla cristata, Salviniaceae) populations in five watersheds within a 56-km2 area of Leeds and Grenville County, Ontario. Some of the recently discovered populations were immense, one containing over two million individuals in 2016. These eastern Ontario populations are persistent, having been observed in situ continuously for four years. One population was confirmed after an apparent absence of at least 30 years and another was reported as present (or at least recurring) for approximately 50 years. We observed that Canadian A. cristata is capable, at least experimentally, of overwinter dormancy and subsequent renewal. Azolla cristata in eastern Ontario and western Quebec appears to represent naturally (if sporadically) occurring populations, likely transported from adjacent northern New York populations by migratory waterfowl. These natural occurrences are expected to be more frequent as climate change continues to reduce environmental barriers to the northward establishment of this and other southern taxa
Swimming as a potentially important emergency capability of Whitethroated Swifts (Aeronautes saxatalis) engaged in aerial mating
Get PDFIt seems reasonable that birds that court or mate in the air over lakes or rivers should be capable of taking off from water or be able to swim, as they might find themselves in the water as a result of this activity. Nonetheless, interaction with water has rarely been documented in the wild and has not been reported for any species of swift in Canada. I report an incident of such activity, however, from Oliver, British Columbia. In this case, I observed a White-throated Swift (Aeronautes saxatalis) swimming vigorously for over 10 minutes before reaching dry land approximately 85 m away. The bird likely fell into the water as a result of flight miscalculations during aerial courtship or mating. I speculate that its swimming capability was aided by the long, narrow, flipper-like wings of the species. I did not observe the bird take flight from the water surface. From these observations, it is evident that White-throated Swifts are relatively strong, capable swimmers, at least for short periods
Oviposition and subsequent depredation of Snapping Turtle (Chelydra serpentina) nests in fresh asphalt
Get PDFOn 28 June 2009, three Snapping Turtle (Chelydra serpentina) nests were found oviposited in fresh asphalt beside a bridge in Algonquin Provincial Park, Ontario. One nest was excavated immediately; the other two were left untouched. The two nests left in situ were revisited on 28 July when it was discovered that one nest had been depredated by an unknown predator. Evidence of the third nest was obliterated by tracks of large mammals crossing the bridge. These observations suggest that predators find turtle nests despite the strong odour of asphalt. To examine potential negative impacts of asphalt on turtle eggs, five clean Snapping Turtle eggs, collected elsewhere in Algonquin Provincial Park, were buried in asphalt on 28 July. After eight days, the translocated eggs had obvious staining and contained 0.081–0.376 μg/g (wet weight) polycyclic aromatic hydrocarbons (PAHs), presumably resulting from asphalt exposure. The risk of exposure to PAHs or other chemicals associatedwith asphalt is unknown, but the levels of PAHs in these eggs appeared lower than those associated with acute toxicity
Summer movements of a radio-tagged Hoary Bat (Lasiurus cinereus) captured in southwestern Ontario
Get PDFHoary Bat (Lasiurus cinereus) is a migratory species known to travel long distances during migration. Little is known about its movement patterns during other periods. An adult male Hoary Bat that we radio-tagged in southwestern Ontario in summer was tracked using the Motus Wildlife Tracking System. It travelled a minimum of 827 km in a circular route over a 2-week period and was last recorded 46 km from the original capture site. Hoary Bat is highly vulnerable to being killed at wind turbines and its propensity to travel great distances during summer and migration may exacerbate the impacts of wind farms
"North American Ducks, Geese & Swans Identification Guide" by Frank S. Todd, 2018. [book review]
No full textRevisiting the hypothesis of sex-biased turtle road mortality
Get PDFRoad mortality poses a major threat to turtle populations. Several studies have suggested that the terrestrial movements associated with nesting increase this risk for females. The Ontario Turtle Conservation Centre (OTCC) is home to the Kawartha Turtle Trauma Centre, which admits 900 or more turtles a year, with road injuries the primary cause of admission. We tested the hypothesis that road mortality in turtles is female-biased using data from injured Midland Painted Turtles (Chrysemys picta marginata), Snapping Turtles (Chelydra serpentina), Blanding’s Turtles (Emydoidea blandingii), and Northern Map Turtles (Graptemys geographica) collected over about 126 000 km2 and admitted to OTCC’s hospital from January 2013 to October 2017. There was no difference in the number of male and female admissions of Midland Painted, Blanding’s, or Snapping Turtles (P > 0.05); however, more female Northern Map Turtles than males were admitted (P < 0.001). Admission of female turtles peaked in June during the nesting season, but male admissions were more evenly distributed throughout the season. Our admissions data provide a temporally unbiased and geographically broad snapshot of turtle–vehicle interactions that can directly inform conservation and management policies. Although our data are not equivalent to mortality rates, these results demonstrate that vehicle strikes can have a substantial impact on both female and male turtles
Habitat selection by Common Gartersnakes (Thamnophis sirtalis) is affected by vegetation structure but not by location of Northern Leopard Frog (Lithobates pipiens) prey
Get PDFUnderstanding the factors affecting habitat selection of species is important for effective management and for conservation because habitat selection affects fitness. We tested the competing, but not mutually exclusive, hypotheses that habitat selection of Common Gartersnakes (Thamnophis sirtalis) at a fine spatial scale is driven by vegetation structure or by Northern Leopard Frog (Lithobates pipiens) prey abundance. We conducted surveys for snakes and frogs in six, 1-ha study grids in eastern Ontario in 2014 and 2015. Common Gartersnakes used areas dominated by forbs more than expected based on availability, and used grassy areas less than expected based on availability. Gartersnakes showed no preference for sites with more frogs. Thus, vegetation structure is important in habitat selection of Common Gartersnakes, but Northern Leopard Frog abundance is not. Common Gartersnakes and Northern Leopard Frogs did have a preference for forbs, but gartersnakes do not appear to be using habitat specifically based on frog abundance at a fine scale. Future work should study habitat use by snakes over a longer period to account for high variability in frog abundance and for temporal changes in habitat structure. Future work should also examine the distribution of other prey items in relation to the distribution of snakes
Long-toed Salamander (Ambystoma macrodactylum) hibernacula in Waterton Lakes National Park revealed using Passive Integrated Transponder telemetry
Get PDFLong-toed Salamanders (Ambystoma macrodactylum) spend most of their lives on land; however, their fossorial nature makes studying their use of habitat difficult. Using Passive Integrated Transponder (PIT) telemetry over two years, we found and characterized nine overwintering sites of Long-toed Salamanders in the vicinity of Linnet Lake and Stable Pond in Waterton Lakes National Park, excavating five of them. These sites were typically associated with stumps and decaying root systems that gave the salamanders access to deep subterranean hibernacula. Overwintering sites were located up to 168 m from the shores of breeding ponds. Given the importance of such terrestrial sites to these populations of Long-toed Salamanders, it is vital that conservation efforts include the preservation of these features and ensure that a sufficient area surrounding breeding ponds remains undisturbed
Roman Snail, Helix pomatia (Mollusca: Helicidae), in Canada
Get PDFPopulations of Roman Snail, Helix pomatia, a large European land snail, are reported for the first time in Canada from disturbed habitats in two distant locations: Sarnia, Ontario and Montrose, British Columbia. As Roman Snail is an edible species subject to international commercial trade, its deliberate, but illegal, introduction into Canada and intentional or unintentional releases are possible sources of these populations