The Canadian Field-Naturalist

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2021-10-05T15:09:25-07:00

Seasonal occurrence of waterbirds in Minas Passage, Bay of Fundy, Nova Scotia, Canada, 2010 to 2012

2020-11-11T18:08:21-08:00

We determined patterns of seasonal abundance and diversity of seabirds and coastal waterfowl in Minas Passage, Bay of Fundy, Nova Scotia, Canada using quantitative, shore-based point surveys from mid-March to late August and mid-October to December 2010 to 2012. This area experiences the world’s highest tides and greatest tidal currents. We showed that species and seasonal cycles of waterbirds in Minas Passage reflect patterns typical of the inner Bay of Fundy and the northeast Atlantic coast of North America. The study highlights the importance of Minas Passage as an important local migration pathway for waterbirds including Black Scoter (Melanitta americana) and Red-throated Loon (Gavia stellata) passing through the Bay of Fundy. Large numbers of sea ducks (Black Scoter, Surf Scoter [Melanitta perspicillata], White-winged Scoter (Melanitta fusca), and Long-tailed Duck [Clangula hyemalis]), and Red-throated Loon were observed at the site in spring and fall, corresponding to known peak movements elsewhere in the Bay of Fundy. Fewest species and smallest abundances of waterbirds overall occurred in summer and early winter, while most species and largest abundances occurred in April-May and early November. Of the 46 species observed, resident breeders such as Herring Gull (Larus argentatus), Great Black-backed Gull (Larus marinus), Common Eider (Somateria mollissima), Black Guillemot (Cepphus grylle), and Double-crested Cormorant (Phalacrocorax auritus), were most abundant in spring to early summer during breeding and migrants including Red-throated Loon, Black Scoter, Ring-billed Gull (Larus delawarensis), Surf Scoter, and Northern Gannet (Morus bassanus) occurred in moderate numbers during migration periods.

An overview of experimental Gray Wolf (Canis lupus) poisoning programs in northern Ontario, 1956 to 1964

2020-09-28T15:48:48-07:00

In the late 1950s, the Ontario Department of Lands and Forests commenced an experimental Gray Wolf (Canis lupus) poisoning program in northern Ontario, the results of which were documented in a series of unpublished reports. Most projects consisted of distributing baits poisoned with strychnine on frozen lakes in late winter; 12 were conducted by district staff and typically consisted of <10 bait stations monitored for two to four months. An intensive three-year program was completed in the Allanwater area, about 250 km north of Thunder Bay, where up to 56 bait stations were distributed on a grid covering >25 000 km2. Thirty eight wolf kills were reported in the district projects and 81 in the Allanwater study. In total, where sex was identified 56% were male and 44% female. Adults made up 51% of the kill in the Allanwater study, subadults (<2 years old) 44%, and 5% were of unknown age. Two hundred and sixty five kills of species other than wolves were documented from all studies, comprising 10 mammal and nine bird species. Common Raven (Corvus corax) and Red Fox (Vulpes vulpes) made up 54% and 24% of the non-target mortality, respectively, and were recorded in most studies. Kills of wolves and non-target species were probably under-reported because animals left bait stations before dying, were buried by snow, were removed by bounty hunters, or monitoring for non-target species was poor. Although completed over 50 years ago, the studies summarized here provide context on the ecological impacts and ethics of poison use to control wolves.

Updated distribution of four stenohaline fish species in Labrador, Canada

2020-09-10T15:19:04-07:00

Distributions of freshwater fish species in Labrador are poorly documented as the region is remote and sparsely inhabited. Here, we update distributions of four species native to the Labrador Peninsula based on data collected over 10 years: Burbot (Lota lota), Round Whitefish (Prosopium cylindraceum), Lake Trout (Salvelinus namaycush), and Slimy Sculpin (Cottus cognatus). In northern Labrador, our findings extend their ranges inland and northwest of their formerly reported distributions. Their presence in previously unknown locations indicates an alternative post-glacial colonization pathway to one previously proposed that suggested an isolated pocket of Lake Trout in a northern coastal area colonized through marine invasion. Instead, we suggest that overland colonization occurred when glacial Lake Naskaupi withdrew across Quebec into several northern drainages. In southern Labrador, we found Lake Trout and Round Whitefish to the southeast of their previously reported ranges. The discovery of an isolated population of Lake Trout in a remote location of southeast Labrador implies that they may have existed in the area historically (6000 years ago), but have undergone a range contraction with a warming climate. In addition, 22 new locations are documented for Lake Trout within their established range.

Vocal repertoire, harmonic structure, and behavioural context in Red-throated Loon (Gavia stellata)

2020-12-09T14:30:36-08:00

Among the five loon species (Gaviidae), Red-throated Loon (Gavia stellata) is the oldest lineage and is the most divergent in morphology and vocalizations. We substantially expand earlier description of calls for a nesting pair and non-breeding birds on Haida Gwaii, British Columbia, Canada. Three major calls used by the nesting pair (Quack, Wail, Plesiosaur) were all low frequency (700–3000 Hz) with multiple harmonics, calls that were also used by non-breeding birds without territories that overnight on freshwater lakes. Call duetting in the Wail and Plesiosaur, as well as sexually dimorphic frequencies and structure within the duets, typically occur in territorial display or pair interactions. The nesting pair used several calls audible only at short distances (Coo, Extended Coo, Staccato, Soft Raack) that were low frequency (200–1200 Hz), graded in behavioural intensity and that resulted in chick responses, including feeding or return to nest. A high amplitude Loud Raack was used by the female and is associated with flight incentives for pre-fledged chicks. Vocalizations of chicks, usually feeding solicitations to the adults, develop from simple chirps in the first week following hatch to more complex calls resembling the Wail and the Plesiosaur calls just prior to fledging. Although the majority of our acoustical descriptions are limited to a single nesting pair where sexes could be differentiated, these represent the first quantification of sound frequency, harmonic structure, and duration, most often associated with context-specific responses, and are suggestive of syntactical content to the vocal repertoire of this basal taxon.

Overall and repeated floral visitation by insects suggests flower flies (Syrphidae) as the major pollinator group of Alaska Wild Rhubarb (Koenigia alaskana var. glabrescens; Polygonaceae) in Northwest Territories, Canada

2020-09-29T15:20:22-07:00

Alaska Wild Rhubarb (Koenigia alaskana var. glabrescens; Polygonaceae) is a native Arctic, subarctic, and alpine plant of northwestern North America. Although the plant has some economic and ecological importance, its biology is poorly known. At 11 sites in the northeast corner of its range in Northwest Territories, we found that 87% of its floral visitors were flies, mostly Syrphidae, a diverse family known to be important pollinators. Insects visiting consecutive flowers on different plants and, thus, likely effecting pollination were also flies (78.6%) and also mostly Syrphidae (72.7%) followed by Hymenoptera (20%). Although syrphids were the dominant potential pollinators at most sites, there was some variation among sites. Our results provide quantitative support for pollinator diversity and the major role of Syrphidae in pollination of Alaska Wild Rhubarb. We suggest that pollination is not a limiting factor in this plant’s spread, nor its rare and local occurrence and restricted distribution, because the majority of its pollinators are widespread.

Salt marsh width positively affects the occurrence of Least and Pectoral Sandpipers in the St. Lawrence River Estuary during fall migration

2020-12-22T02:56:23-08:00

Salt marshes are vulnerable to climate change-associated sea-level rise and storm-induced surges. Their degradation will likely affect shorebirds relying on this ecosystem. Least Sandpiper (Calidris minutilla) and Pectoral Sandpiper (Calidris melanotos) migrating along coastline habitats typically use salt marshes to rest and replenish their body reserves. Our objective was to test if width of the different vegetation zones within salt marshes affects the occurrence of Least and Pectoral Sandpipers stopping along the St. Lawrence River Estuary, Quebec, Canada, during fall migration. We established 26 survey sites, each 600 m in length, along the shoreline. Shorebird surveys were conducted in 2011 and 2012. We characterized salt marshes by measuring the width of each vegetation zone (lower marsh and upper marsh). We analyzed shorebird presence/not detected data with generalized estimating equations to test the predictions that occurrence of Least Sandpipers and Pectoral Sandpipers increases with width of both the lower and upper marsh. Upper marsh width was positively associated with probability of occurrence in each species. Our results highlight the importance of protecting the integrity of salt marshes for these two species. In the St. Lawrence River Estuary, where landward migration of salt marshes is no longer possible (coastal squeeze), effective management of shorelines is much needed. Otherwise, salt marshes and these two species could be locally jeopardized.

Cover

2021-10-04T16:40:37-07:00

News and Comment

2021-10-02T20:10:41-07:00

The first documented migration of a potter wasp, Ancistrocerus adiabatus (Hymenoptera: Vespidae: Eumeninae)

2020-11-13T09:49:27-08:00

Eumenine wasps are not known to be migratory and have never been proposed as migrants, let alone documented as such. We document a large-scale migration of a common eumenine, Ancistrocerus adiabatus, during which 44 000–68 000 wasps moved through a known migration corridor in southwestern Ontario, Canada, in less than an hour. Evidence for migration of another eumenine, Pachodynerus erynnis, six species of flower flies (Diptera, Syrphidae), and two dragonflies (Odonata) is also provided. We hope that this note encourages naturalists to focus their attention on insects at known migration concentration sites to learn more about this grossly understudied aspect of animal behaviour.

Coyote (Canis latrans) predation of colonial rodents facilitated by Golden Eagles (Aquila chrysaetos)

2020-07-27T15:00:26-07:00

Interactions between Coyote (Canis latrans) and Golden Eagle (Aquila chrysaetos) are complex and likely not yet fully documented or understood. I observed a Coyote prey on a Black-tailed Prairie Dog (Cynomys ludovicianus) at the edge of a large colony in Grasslands National Park, Saskatchewan. The prairie dogs were vigilant toward three Golden Eagles circling above, and the Coyote apparently used this to its advantage. As such, the eagles appeared to facilitate the ability of the Coyote to rush in virtually undetected and prey on a prairie dog that was distracted by the avian predators. This observation is of scientific interest because it is another example of the varied interactions between Coyotes and Golden Eagles, which is competitive and includes kleptoparasitism.

Behavioural interactions among Canada Lynx (Lynx canadensis) during pre-estrous

2020-09-25T20:30:13-07:00

Information is lacking on the behaviour of free-roaming Canada Lynx (Lynx canadensis) during the breeding season, likely because they are rarely observed in the wild. Other wild solitary felid males compete with each other to mate with promiscuous females. However, the behavioural context or sequence of this competition among wild male Canada Lynx remains unreported. We describe the behaviour of three adult wild lynx during the breeding season. We observed the first two lynx together; an adult male and an inferred adult female remained together non agonistically for nearly 2 h before they were interrupted by another adult male. Our observation of interaction between the two males includes agonistic behaviours, vocalizations, scent marking, fighting, and a long-distance (1.7-km) expulsion of the intruding male lynx by the first male. These observations add to the limited information available on the social ecology of lynx during the breeding season.

Editors’ Report for Volume 134 (2020)

2021-10-02T20:15:37-07:00

Changes to the Book Reviews and New Titles Sections

2021-10-02T19:51:53-07:00

"Wildlife Management and Landscapes: Principles and Applications" edited by William F. Porter, Chad J. Parent, Rosemary A. Stewart, and David M. Williams, 2021. [book review]

2021-10-02T19:55:30-07:00

"Stories of Predation: 60 Years of Watching Wildlife" by Dick Decker, 2021. [book review]

2021-10-02T19:59:57-07:00

"Yellowstone Wolves: Science and Discovery in the World’s First National Park" edited by Douglas W. Smith, Daniel R. Stahler, and Daniel R. MacNulty, 2020. [book review]

2021-10-02T20:03:27-07:00

New Titles

2021-10-02T20:07:19-07:00