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Fishers (Pekania pennanti) are a mid-sized forest-dwelling carnivore in the family Mustelidae, once widely distributed across the northern US and Canada. Between 1800 and 1940, they were extirpated across much of their former range through commercial fur harvesting and habitat modification. Glacier National Park (GNP), which maintains a wildlife sighting database containing public and agency sighting and track records of Fishers from 1947 through the present, presumed Fishers extant in the park. Over 2007–2012, GNP made opportunistic efforts to collect Fisher DNA in hair traps but were unsuccessful. In 2013 and 2015, GNP conducted a more intensive effort to document the occurrence of Fishers by systematically placing baited hair traps within putative Fisher habitat across the park. These efforts were also unsuccessful and I show through application of Bayes' Theorem that a resident population of Fishers in GNP is highly improbable. Past credible sightings of Fishers in GNP were probably animals dispersing from occupied habitats to the west of GNP, and I suggest that regular occurrence of deep, unconsolidated winter snow may have prevented Fishers from occupying GNP in the past.
Effective species management requires knowledge of species distributions, but surveys for cryptic species near the boundaries of their geographical ranges can be difficult. We used environmental DNA (eDNA) and occupancy modeling to examine the distribution of Northern Red-legged Frogs (Rana aurora) and federally threatened California Red-legged Frogs (Rana draytonii) in a sample of 60 forested stream sites near where their ranges meet in southern Mendocino County, California, USA. For both species, the probability of occurrence (ψ) in forest streams in our study area was very low: California Red-legged Frog ψ was <0.01 (95% credible interval = <0.01–0.05), and Northern Red-legged Frog ψ was 0.07 (0.02–0.15). DNA from both species was found at 1 pond site, suggesting either co-occurrence or introgression. Our results suggest that abundance, stream use, or both are very low for red-legged frogs in forested streams in southern Mendocino County.
We explored changes in seasonal distribution and behavior of waterbirds in the Strait of Georgia, Canada, in response to increased presence of a major avian predator, the Bald Eagle (Haliaeetus leucocephalus). Eagles were widespread and their increase through fall and winter coincided with migratory movements of waterbirds. Many species of waterbird used inshore waters in early fall when eagles were scarce. Diving birds moved away from inshore waters when eagles returned in late fall and winter, whereas dabbling ducks formed large flocks in inshore waters and spent proportionally more time being vigilant as winter progressed. Flock sizes and avoidance flight distances of scoters and dabblers, but not gulls, increased with proximity to eagles. Waterbirds did not alter vigilance with distance to eagles. We discuss our findings in context of management issues regarding apparent declines and importance of understanding indirect effects of predators on prey for wildlife monitoring.
After initial colonization of the Strait of Georgia in the late 19th and early 20th centuries, nesting populations and number of colonies of Pelagic Cormorant (Phalacrocorax pelagicus) and Double-crested Cormorant (P. auritus) increased in abundance until 1987, but subsequently both species declined by 2000. To update population status, we conducted surveys of 45 Pelagic Cormorant and 24 Double-crested Cormorant nesting colonies in 2014, and supplemented this survey with recent and historic counts conducted from 1955 to 2015. We modeled changes in population size over 6 decades to measure long-term population changes, and found strong non-linear trends that varied widely among colonies. Using years when all known colonies in the Strait of Georgia were surveyed, we documented that the Pelagic Cormorant population increased from 961 to 2234 nests in 1959–1974, remained fairly stable (approximately 2250–2450 nests) from 1974 to 1987, decreased after 1987 to approximately 1100 nests in 2000, and then rose slightly to approximately 1400 nests in 2014. The Double-crested Cormorant population increased from approximately 250 nests from 1959–1960, to approximately 1900 nests in 1987, before decreasing to approximately 600 nests in 2000, and remaining at this level through 2014. Many smaller colonies of both cormorant species no longer exist, and the majority of Pelagic and Double-crested Cormorants currently nest on Mandarte Island, Mitlenatch Island, and 3 bridge locations (Second Narrows, and Burrard & Granville) in Vancouver. The main factors apparently causing decline after 1987 are increased predation and disturbance by Bald Eagles (Haliaeetus leucocephalus), a potential reduction in availability of forage-fish prey, and human disturbance. Remaining large colonies offer some protection from eagle impacts (cliff habitats or man-made structures) or alternate avian prey for Bald Eagles, such as Glaucous-winged Gulls (Larus glaucescens) at Mandarte and Mitlenatch islands. In 2013–2015, small numbers of Brandt's Cormorants (P. penicillatus) nested at Mandarte Island. Continued monitoring is needed to track changes in populations and nesting locations and to inform management of cormorants in the Strait of Georgia.
KEYWORDS: Balaenoptera physalus, Fin Whales, movements, North America, photo-identification, population recovery, predation, prey, ship strike, Vancouver Island
Historically, Fin Whales (Balaenoptera physalus) were relatively common off the west coast of North America but very few records of their occurrence in waters between Vancouver Island and continental North America exist. To confirm their presence in these waters we collected photographs documenting at least 13 unique individuals during 43 encounters from 1999 to 2017. These records are the first of live Fin Whales in Queen Charlotte, Johnstone, Georgia and Juan De Fuca Straits and are also the only confirmed sightings between Vancouver Island and continental North America since 1930. Additionally, 12 dead Fin Whales all with evidence of ship strikes are reported in these waters between 1986 and 2017. Most (88%) sightings of live Fin Whales occurred between July and October and no individuals were documented dead or alive between January and April. We suggest that Fin Whales in coastal waterways may be at greater risk to ship strikes and predation by mammal-eating Killer Whales (Orcinus orca) than in less confined waters further offshore.
In the northwest, White-headed Woodpeckers (Picoides albolarvatus) are an uncommon species restricted to interior, dry coniferous forests. This species forages primarily by probing in bark crevices, surface gleaning, and excavating below the bark. Here we report on an observation from Mt. Ashland in southern Oregon of a White-headed Woodpecker feeding on insects in and around the sporophores of Veiled Polypore (Cryptoporus volvatus). Inspection of other sporophores with signs of woodpecker feeding revealed abundant fly larvae and beetles (adults and larvae). This widespread decay fungus colonizes the sapwood of recently dead trees where it is frequently associated with bark beetles. A suite of other insects is attracted to the sporophore, many using the enclosed pouch as a pupation chamber. In addition to exploring the significance of C. volvatus as a foraging substrate for White-headed Woodpeckers, we discuss the potential role of White-headed Woodpeckers as dispersal agents for C. volvatus and the possible interplay between C. volvatus-induced decay, insect availability, and habitat selection by White-headed Woodpeckers.
We report the 2nd occurrence of a warm water teleost predator, Swordfish (Xiphias gladius), in Canadian Pacific waters, and the first seen in coastal waters of British Columbia. A Swordfish was observed on 5 September 2017 approximately 20 nm (37 km) from the Brooks Peninsula, Vancouver Island, British Columbia (UTM: Zone 9, 560062 E, 5526365 N, WGS84) in above average water temperatures.
On 16 April 2016, a nesting pair of Black-backed Woodpeckers (Picoides arcticus) were illegally killed by a poacher near Rimrock Lake, Washington. We captured the incident on camera and were surprised to observe a female Black-backed Woodpecker visit the partially excavated nest cavity a mere 3 h after the “removal” of the breeding pair (and presumed territory holders). Within 72 h, a male and female were both observed at the abandoned nest and began excavating the partially completed cavity. The intruding pair successfully fledged 2 young from this nest on 10 June 2016. To our knowledge, this is the 1st reported case of a pair of Black-backed Woodpeckers taking over excavation duties at a cavity started by another pair in the same breeding season. While formal studies are needed, this incident suggests conspecific attraction may be used for territory settlement in Black-backed Woodpeckers.
On 22 February 2015, a single specimen of Caretta caretta was identified in surface waters about 45 nm west of Tofino, British Columbia. The animal's carapace was covered with algae, but the specimen was identified based on shell shape, head size, and the color of its parietal and interparietal scales. This record confirms that 4 sea turtle species range into British Columbia's coastal waters.
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