The Canadian Field-Naturalist (E-Journal)
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Barred Owl (Strix varia) activity and diet recorded with a camera trap at a natural cavity nest in Manitoba, Canada (2016–2017)
No full textCamera trap images (n = 27 092) collected at a natural Barred Owl (Strix varia) nest site in Manitoba, Canada, 2016–2019, were used to quantify nesting behaviour and identify prey delivered to the nest. Adult Barred Owl activity increased prior to egg laying and again after incubation. Adults were mostly active at night, but daytime activity increased during the nestling period in 2016 and more so with a larger brood in 2017. Nestlings were active at the nest entrance both day and night for 8–9 days prior to fledging at ≤27–32 d old. Two of three nestling activity peaks (0400 and 2000 Central Daylight Time [CDT]) corresponded to prey delivery activity peaks whereas a third (1200 CDT) did not. Only 31/65 prey were identified to species, but 12 new prey taxa were documented for Barred Owl in Manitoba. Activity at the cavity during the non-breeding season before and after a nest predation event were documented; the nest site was abandoned after an American Black Bear (Ursus americanus) visited the nest cavity in May 2018. Factors affecting the quality and quantity of images, and hence data obtained from them, included camera position relative to the nest cavity entrance, light levels, camera trigger speed, non-target species, and the configuration and settings of motion detection sensors. Improved camera traps may overcome these limitations. This is the first published study on this owl species using this increasingly popular technology
"The Jewel Box: How Moths Illuminate Nature’s Hidden Rules" by Tim Blackburn, 2023 [book review]
No full textEnglish
No full textConservation of wildlife populations requires reliable information on population size, trends, and demographic processes.Such information is sparse for Red-necked Grebe (Podiceps grisegena), a species that is vulnerable to changing wetland conditions in the prairie pothole region. During 2008–2019, I collected breeding pair and reproductive estimates of a recentlyexpanded Red-necked Grebe population on 109 semi-permanent and permanent wetlands (mean ± SE: 2.92 ± 0.41 ha, range 0.01–24.2) in agriculturally-dominated habitat in southwestern Manitoba, Canada, to determine population status and reproductive success. I also looked for effects of changing wetland water levels and the presence of conspecifics and/or wetland size on productivity. Red-necked Grebe breeding densities were the highest reported for solitary-nesting pairs in North America and the breeding population currently appears to be stable. I found that chicks/breeding pair are mostly lower but chicks/successful pair are similar or greater than values reported from other studies. Pairs breeding with conspecifics appeared to be as productive as those on single-pair wetlands. Productivity was positively associated with wetland water levels suggesting that prolonged drought or climate change leading to warmer, drier summers on the prairies could reduce Rednecked Grebe breeding populations
The “perrrck” vocalization of Ruffed Grouse (Bonasa umbellus)
No full textThe vocal repertoire of Ruffed Grouse (Bonasa umbellus) has been known for decades, but because of the rarity of vocal recordings in the field, few data exist on spectral characteristics of their vocalizations. Here, we provide a spectrogram and analysis of a vocalization rarely heard in the field: the “perrrck” call, which is ~0.5 s in duration and has a fundamental frequency of 613 Hz with several harmonics. We compare this call with the more commonly heard “peet” call, which is much shorter and of higher frequency. Although the function of the perrrck call remains unknown, our analyses show that Ruffed Grouse vocalizations vary in frequency, despite their purportedly weak syrinx
"Essential Entomology. Second Edition" by George McGavin and Leonidas-Romanos Davranoglou, illustrations by Richard Lewington, 2022 [book review]
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"Restoring the Balance: What Wolves Tell Us about Our Relationship with Nature" by John A. Vucetich, 2024 [book review]
Full text linkSnow-surface activity of California Snow Scorpionfly, Boreus californicus (Mecoptera: Boreidae), in western Montana, USA
No full textThe flightless California Snow Scorpionfly (Boreus californicus Packard) has rarely been studied, and knowledge of its distribution and activity on snow remains fragmentary. I found it on snow surfaces in western Montana, USA, from valley grasslands to subalpine conifer forests and above the tree line. At lower elevations (991–1500 m), B. californicus was present on snow from early November to early March, at higher elevations (1800–2850 m), from early October to early January as well as late June. The species has now been documented in western Montana over an elevation gradient of nearly 2000 m and is probably active somewhere on snow in most months except in mid- and late summer. When the insect was present on snow, surface temperatures ranged from −5.0°C to 5.5°C. Pairs in copula (n = 26) were found when snow surface temperature was −0.5°C to 5.5°C. Mating occurred on snow at low elevations from November to late February, at high elevations in late June. The mating period in subalpine habitat, and probably above the tree line, includes early summer as well as late autumn to spring because of the colder temperatures and lingering snow in spring and earlier snowfall in autumn. Temperature and snow-cover characteristics affect the snow-surface ecology of B. californicus across its range in western Montana. Mating on a snow cover is likely related to greater mobility (ability to jump) on snow surfaces, aiding the search for mates and contributing to greater dispersal of eggs and reduced inbreeding
Stream restoration: a key to the survival and recovery of the Endangered Western Brook Lamprey (Lampetra richardsoni), Morrison Creek population: Stream remediation - key for the survival and recovery of species at risk
No full textAquatic ecosystems and species are increasingly threatened by anthropogenic activities. Stream restoration has thereforebecome a necessary conservation strategy to improve habitat quality and quantity, which are key components of productive, healthy, resilient aquatic ecosystems. The Morrison Creek watershed on Vancouver Island, British Columbia has been impacted by anthropogenic activities resulting in the degradation of aquatic habitat. For an Endangered, range-restricted species like Western Brook Lamprey (Lampetra richardsoni), Morrison Creek population, which only occurs in this one watershed, any habitat-related impacts have the potential to cause population level declines, thereby increasing the risk of extinction. Stream and riparian restoration were therefore undertaken to ameliorate the species’ Critical Habitat, which no longer supported spawning and early rearing. Effectiveness of restoration was determined through the use of restored areas for spawning, increased hydraulic complexity, and reduced sedimentation. Lamprey (adults and larvae) and salmonids (Oncorhynchus spp.) had not been observed in this habitat since 2005; however, following habitat restoration in 2021, 10 different lamprey nests were observed being tended in the restored habitat in 2022. Salmonids were also observed using the newly created habitat for spawning in fall 2021 and fry and smolts used pools and riffles for rearing the following spring and summer. Our work demonstrates specific types of habitat restoration that are effective for lamprey conservation and validates that complex restoration activity can occur when there is effective collaboration