Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears

Put, Julia E.; Put, Laurens; Clair, Colleen Cassady St.

doi:10.3897/natureconservation.21.12429

Cited by 4 publications

(4 citation statements)

References 39 publications

(38 reference statements)

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“…This observation caused us to explore the possibility that red squirrels (Tamiasciurus hudsonicus) living adjacent to the rail cached grain that was later excavated by bears, potentially conditioning them to seek grain on the rail. As predicted, squirrels occurred at higher densities near the rail where we also found middens containing agricultural products [51]. We also saw (via remote camera) a young study bear excavate a midden containing grain and found evidence of digging at several others.…”

Section: Synthesis Of Resultssupporting

confidence: 82%

Animal learning may contribute to both problems and solutions for wildlife–train collisions

Clair

Backs

Friesen

et al. 2019

Phil. Trans. R. Soc. B

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Transportation infrastructure can cause an ecological trap if it attracts wildlife for foraging and travel opportunities, while increasing the risk of mortality from collisions. This situation occurs for a vulnerable population of grizzly bears ( Ursus arctos ) in Banff National Park, Canada, where train strikes have become a leading cause of mortality. We explored this problem with analyses of rail-associated food attractants, habitat use of GPS-collared bears and patterns of past mortality. Bears appeared to be attracted to grain spilled from rail cars, enhanced growth of adjacent vegetation and train-killed ungulates with rail use that increased in spring and autumn, and in areas where trains slowed, topography was rugged, and human density was low. However, areas with higher grain deposits or greater use by bears did not predict sites of past mortality. The onset of reported train strikes occurred amid several other interacting changes in this landscape, including the cessation of lethal bear management, changes in the distribution and abundance of ungulates, increasing human use and new anthropogenic features. We posit that rapid learning by bears is critical to their persistence in this landscape and that this capacity might be enhanced to prevent train strikes in future with simple warning devices, such as the one we invented, that signal approaching trains. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation’.

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Section: Synthesis Of Resultssupporting

confidence: 82%

Animal learning may contribute to both problems and solutions for wildlife–train collisions

Clair

Backs

Friesen

et al. 2019

Phil. Trans. R. Soc. B

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“…), and even inter‐specific food conditioning (Put et al. ). Small changes in any foraging opportunity are likely to be important to grizzly bears, which are generally limited by access to protein (Hilderbrand et al.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the coincidental timing of lower elk abundance and increased frequency of grizzly bear railway collisions, our study found no support for the hypothesis that highway mitigation caused an increase in the frequency of train collisions with grizzly bears, but there is some evidence that it increased collision rates for ungulates other than elk. Separate from the effect of highway mitigation, grizzly bears may be attracted to the railway for several food-related benefits, such as the attraction to wildlife associated with spilled grain (Gangadharan et al 2017), increased plant growth , and predation and ungulate scavenging opportunities (Murray et al 2017), and even inter-specific food conditioning (Put et al 2017). Small changes in any foraging opportunity are likely to be important to grizzly bears, which are generally limited by access to protein (Hilderbrand et al 1999, L opez-Alfaro et al 2015 especially in this landscape (Garshelis et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Wildlife mortality on roads and railways following highway mitigation

et al. 2019

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Wildlife mortality caused by collisions with vehicles on roads is increasingly and effectively mitigated with exclusion fencing and crossing structures, but this solution potentially changes wildlife habitat use and distribution to increase the risk of mortality on adjacent, unmitigated railways. We investigated this potential side‐effect of mitigating the TransCanada Highway, which was completed in sections between 1983 and 2013, on the rate of wildlife mortality on the nearby transcontinental mainline of the Canadian Pacific Railway in Banff National Park. For each transportation class (highway and railway), we calculated collision rate as the number of collisions per year and km for two guilds (carnivores and ungulates) before and after mitigation occurred between 1981 and 2014. We constructed additional models for each transportation class and each of four species groups with adequate sample sizes: elk (Cervus canadensis), other ungulates (family Cervidae), bears (Ursus spp.), and coyotes (Canis latrans). Across guilds, mortality rates declined after mitigation, particularly on the highway (as expected) and most strongly for ungulates. For individual species groups, mortality on the railway for elk was best predicted by year and population size, without the inclusion of mitigation status on the adjacent highway. However, collision rates on the railway increased after mitigation for other ungulates (mostly deer, Odocoileus spp.) while also increasing over time. Collision rates on the railway increased over time for bears, but not in relation to highway mitigation. We found no evidence that the spatial distribution of collisions on the railway changed after highway mitigation, as might be expected from a funneling effect of crossing structures. Our results support and extend previous work demonstrating that exclusion fencing and wildlife crossing structures reduce wildlife mortalities on the highway at this location, and provide limited evidence, for other ungulates alone, that such mitigation may increase mortality on the adjacent railway. Similar analyses are warranted in other locations, particularly mountainous regions, where major transportation features often occur in close proximity.

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“…As in a concurrent study (Hamer 2016), I attributed all excavations found in middens to bears, and all excavated middens I observed contained either Whitebark Pine or Limber Pine cones or cone scales; only one of these excavated middens contained both Whitebark Pine and Limber Pine cones (Hamer 2016), and it was not possible to quantify the five-needle pine cones or cone scales in the middens. Bears also excavate middens found at valley-bottom beside the Canadian Pacific Railway in Banff National Park to obtain anthropogenic seeds gathered by Red Squirrels from railway car spillage (Put et al 2017); these excavations, being distant from Whitebark Pine and Limber Pine, are not pertinent to my study. If I found an excavated Red Squirrel midden containing Whitebark Pine cones or cone scales, I classified this location as a putative Whitebark Pine feeding site, and I inferred that bears with GPS fixes (see Table 1) near this site had consumed Whitebark Pine seeds.…”

Section: Methodsmentioning

confidence: 99%

Use of Whitebark Pine (<i>Pinus albicaulis</i>) seeds by GPS-collared Grizzly Bears (<i>Ursus arctos</i>) in Banff National Park, Alberta

Hamer¹

2021

Can Field Nat

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Seeds of Whitebark Pine (Pinus albicaulis) are a major food for Grizzly Bears (Ursus arctos) in the Yellowstone ecosystem. In Canada, Grizzly Bears are known to eat Whitebark Pine seeds, but little additional information, such as the extent of such use and habitat characteristics of feeding sites, is available. Because Grizzly Bears almost always obtain Whitebark Pine seeds by excavating cones from persistent caching sites (middens) made by Red Squirrels (Tamiasciurus hudsonicus), it is possible to infer Whitebark Pine feeding when bears are located near excavated middens in Whitebark Pine stands. During 2013–2018, I conducted a retrospective study in Banff National Park using data from 23 Grizzly Bears equipped by Parks Canada staff with global positioning system (GPS) collars. My objectives were to use GPS fixes to determine the percentage of these bears that had been located in close proximity to excavated middens containing Whitebark Pine seeds and to describe the habitat at these excavated middens. I linked 15 bears (65%) to excavated middens and, by inference, consumption of Whitebark Pine seeds. Excavated middens occurred on high-elevation (mean 2103 ± 101 [SD] m), steep (mean 26° ± 8°) slopes facing mostly (96%) north through west (0–270°). Use of Whitebark Pine seeds by at least 65% of the 23 studied Grizzly Bears suggests that conservation of Whitebark Pine in Banff National Park would concomitantly benefit the at-risk population of Grizzly Bears.

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Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears

Cited by 4 publications

References 39 publications

Animal learning may contribute to both problems and solutions for wildlife–train collisions

Animal learning may contribute to both problems and solutions for wildlife–train collisions

Wildlife mortality on roads and railways following highway mitigation

Use of Whitebark Pine (<i>Pinus albicaulis</i>) seeds by GPS-collared Grizzly Bears (<i>Ursus arctos</i>) in Banff National Park, Alberta

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