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Temporal Variation in Food Habits of the American Black ( americanus ) in the Boreal Forest of Northern

Derrick A. r OmAiN 1, 3 , m ArTyN e. O BBArD 2, 4 , and JAmes L. A TkiNsON 1

1Department of science, University of Guelph, Guelph, Ontario N1G 2W1 2Wildlife research and Development section, Ontario ministry of Natural resources, DNA Building, Trent University, 2140 east Bank Drive, Peterborough, Ontario k9J 7B8 canada 3current address: Ontario ministry of Natural resources, 5520 Hwy 101 e., P.O. Bag 3090, south Porcupine, Ontario P0N 1H0 canada 4corresponding author; e-mail: [email protected] romain, Derrick A., martyn e. Obbard, and James L. Atkinson. 2013. Temporal variation in food habits of the ( Ursus americanus ) in the boreal forest of northern Ontario. canadian Field-Naturalist 127(2): 118–130. We used scat analysis to investigate temporal variation in the food habits of American Black ( Ursus americanus ) in the boreal forest of northern Ontario. specifically, we examined whether there was a seasonal shift in foraging over three (1990–1992) and which foods, if any, varied in occurrence among years. American Black Bears ate foods ranging from green vegetation in the spring to ants in mid-summer and and nuts in late summer and fall. Late summer forage, especially ( spp.), varied greatly among years. American Black Bears in northern Ontario consumed a variety of foods opportunistically. Understanding how American Black Bears in northern Ontario exploit food resources and how these food items vary among years can provide insights into demographic processes and help wildlife managers better anticipate changes in the structure of the harvest of American Black Bears and in human–bear conflict levels. in northern Ontario, forest management practices that increase the availability of early successional species would be beneficial to American Black Bear populations. key Words: American Black Bear; Ursus americanus ; ; early Lowbush ; Vaccinium myrtil - loides ; Velvet-leaved Blueberry; annual variability; boreal forest; diet; feeding ecology; food habits; foraging; scat analysis; Ontario studies of food habits of American Black Bears ber of American Black Bears harvested and the pro - (Ursus americanus ) have covered an array of climatic portion of females in that harvest to ensure they remain and geographical locations, from to Virginia within sustainable levels (mcLaren et al. 2009*). Due (Hatler 1972; Landers et al. 1979; Beeman and Pelton to the importance of adult females in the population 1980; Hellgren and Vaughan 1988; raine and kansas dynamics of American Black Bears (Obbard and Howe 1990; Holcroft and Herrero 1991; schwartz and Franz - 2008), outfitters and other hunters are encouraged to mann 1991; Boileau et al. 1994; kasbohm et al. 1995). direct harvest towards males (Obbard et al. 2008). Nevertheless, such studies should be replicated geo - Here we report on the food habits of American Black graphically and temporally because the type, phenology, Bears in the boreal forest of northern Ontario, an and relative abundance of foods consumed by Ameri - understanding of which could help explain variations can Black Bears vary from location to location and sea - in the American Black Bear harvest and in levels of son to season. Natural foods can also vary in abundance conflict between humans and American Black Bears. among years, significantly affecting survival and repro - This knowledge could help wildlife managers under - ductive success of American Black Bears (rogers 1976, stand when to expect increases in the proportion of adult 1987; czetwertynski et al. 2007; Obbard and Howe females in the harvest and when to anticipate changes in 2008) as well as space use patterns (Powell et al. 1997). levels of conflict between humans and American Black Variation in the phenology and abundance of natural Bears. foods among years has been linked directly to variation Because annual variation in natural foods of bears in numbers of American black bears that are harvested is common, studies of more than two years’ duration (ryan et al. 2004), to changes in the structure of the are necessary to capture annual fluctuations and trends harvest of American Black Bears (Noyce and Garshelis (korschgen 1980; mcLellan and Hovey 1995). Our 1997), and to variation in levels of conflict between objectives were (1) to document general food habits of humans and American Black Bears (Howe et al. 2010). American Black Bears in the boreal forest of Ontario Adult female American Black Bears are more vulner - and (2) to determine, over a three- period, whether able to hunting pressure in the fall during years of food there was seasonal and yearly variation in the propor - failure (Noyce and Garshelis 1997). As a result, in tions of food items ingested by American Black Bears Ontario, wildlife managers monitor both the total num - in the boreal forest.

118 2013 rOmAiN eT AL .: B OreAL FOresT BLAck BeAr FOOD HABiTs 119

Study Area able for any future nutritional studies. We also report The study area was located approximately 25 km frequency of occurrence to enable comparison with north of chapleau, Ontario, in the southeastern portion other studies. of the chapleau crown Game Preserve (48°10'N, Holcroft and Herrero (1991) arbitrarily suggested 83°20'W; Figure 1). A variety of logging roads criss - that a 25% subsample should be representative of an crossed the 400-km 2 study area, which was within the entire scat. However, we developed a subsampling tech - missinaibi–cabonga Forest section of the southern nique that showed that a 10% subsample of each scat Boreal Forest region (rowe 1972). During 1990 – was representative of the contents of the entire scat. To 1992, mean temperatures in January and July were determine this, we thoroughly mixed and homogenized −13.6°c and 15.7°c, respectively; mean annual pre - one randomly selected dried scat from each season on cipitation was 87.5 cm (chapleau station, 47°49'12"N, a dissecting tray and divided each into subsamples. We 83°20'48'W; environment canada 2013). The study then compared the contents of 10%, 25%, and 65% area was dominated by typical boreal forests with subsamples by mass using spearman rank correlation monoculture stands of ( Pinus banksiana) and and found no difference among the three subsample spruces ( Picea spp.) along with mixtures of mature sizes ( P > 0.05), suggesting that a 10% dry mass sub - boreal mixedwood stands with intermediate succes - sample of each scat was sufficient for analysis (romain sional and recently logged (10–20 years previously) 1996). and replanted areas. During may–October 1990–1992, we collected scats Logging and periodic wildfires resulted in a mosa - daily along a 30-km network of tertiary gravel roads ic of different-aged forest stands (Ontario ministry of throughout the study area, and occasionally from live Natural resources 1984*). major overstory species traps used to capture American Black Bears for a were Jack Pine, Black spruce ( ), White demographic study (Obbard and Howe 2008). in order spruce ( ), Balsam Fir ( ), to limit bias from anthropogenic sources, we did not Trembling Aspen ( Populus tremuloides ), Paper Birch collect scats from within a 2-km radius of a small land - ( ), eastern White cedar ( fill in the study area; this approximated the average occidentalis ), and Tamarack ( ), with radius of the home range of adult female American abundant ( Alnus spp.), mountain maple ( Acer Black Bears in the area (schenk et al. 1998). scats spicatum ), Balsam Poplar ( Populus balsamifera ), and therefore typically contained only naturally occurring ( Salix spp .) in the understory. important - foods. producing species in the understory and ground cover We placed scats separately in labeled plastic bags were Pin cherry ( Prunus pensylvanica ), serviceberries and froze them at −20°c within 4 hours of collection. ( spp .), mountain-ashes ( Sorbus spp .), For analysis, we thawed individual scats, strained them Beaked ( Corylus cornuta ), early Lowbush by washing through three-layered mesh sieves (Pre - Blueberry ( Vaccinium angustifolium ), Velvet-leaved cision scientific co., chicago, illinois; aperture sizes Blueberry ( V. myrtilloides ), Bunchberry ( Cornus cana - 5.0, 2.0, and 0.833 mm) to remove small fragments, and densis ), raspberries ( Rubus spp .), currants ( Ribes spp .), then dried them to a constant mass in a drying oven Bristly sarsaparilla ( Aralia hispida ), and Wild sarsa - at 40–50°c for 24–48 hours. We assigned scats to five parilla ( A. nudicaulis) . periods: may, June, July, August, and september–Octo - ber (september and October were combined because Methods of the small sample sizes). scat analysis is a common technique used to study in order to monitor seasonal availability of food habits of carnivores (klare et al. 2011); however, species that we might expect to find in scats and to it can be tedious and labour-intensive, due to the effort obtain representative specimens for comparison with required to identify fecal remains. As a result, a num - scat contents, we compiled phenological data within ber of techniques have been developed to reduce the major habitat types on a weekly basis from early may time required for effective scat analysis. These tech - to August 1990–1992. We sampled 20 10-m 2 quadrats niques vary from visual estimates (Tisch 1961; Hatler selected to represent all major habitat types in the study 1972) to visual volume estimates (Grenfell and Brody area. We monitored development of a few plant species 1983; irwin and Hammond 1985) coupled with fre - not found in the quadrats in areas near established quency of occurrence. Other researchers have used quadrats or along roadsides. point sampling (Boileau et al. 1994) and volume meas - After consulting a reference list of for the ured by water displacement (Landers et al. 1979; Hol - study area (Brunton 1982*), we collected reference croft and Herrero 1991). samples of potential food items at different pheno - Because information on dry mass of food items is logical stages during 1991, 1993, and 1994, including essential to studies of nutrition or food energetics , berries, and seeds. We collected hairs of known (korschgen 1980; robbins et al. 2004), we elected to specimens of potential prey from carcasses base our scat content estimates on the mass of dried, encountered. We also identified food items from fresh hand-sorted food items in order to make our data avail - scats; this helped us to identify the components of 120 THe cANADiAN FieLD -N ATUrALisT Vol. 127

FiGUre 1. Location of study area (black polygon) in the southeastern portion of the chapleau crown Game Preserve in northern Ontario, 1990-1992. inset shows location of chapleau crown Game Preserve and surrounding area relative to the rest of the province. dried scats. We used keys and manuals to identify grass - Our null hypothesis was that diet did not vary es (musil 1963; Brown 1979), herbaceous plants, among periods and years. We used two-way analysis , and trees (Petrides 1958; symonds 1963; Peter - of variance (ANOVA) (kuehl 1994; sAs institute inc. son and mckenny 1968; soper and Heimburger 1982; 1990) to compare the dry mass percentage of indi - Baldwin and sims 1989), and seeds (martin and vidual food item categories among periods and years. Barclay 1961; musil 1963; montgomery 1977), insects We based post-hoc pairwise comparisons on ’s (Bland 1958), and hairs (Adorjan and kole - least significant difference (LsD) test (sokal and rohlf nosky 1969*; moore et al. 1974; Thompson et al. 1981). To approximate normality, we arcsine square 1987). We attempted to separate all species of forbs root transformed the aggregate percentage mass data and herbaceous material, but this was not possible in (korschgen 1980). Differences were considered sig - some scats. Accordingly, we pooled these as “green nificant at P < 0.05. vegetation.” 2013 rOmAiN eT AL .: B OreAL FOresT BLAck BeAr FOOD HABiTs 121

Results Brome ( Bromus ciliatus ), common Timothy (Phleum During the 1990–1992 field seasons, we collected pretense ), bulrushes ( Scirpus spp.), yellow sedge 1023 scats (373 in 1990, 340 in 1991, and 310 in 1992). ( flava ), and other Carex species . The number of scats collected varied somewhat among Fruits were not prominent in the diet until July, periods. For example, during the August and septem - August, and september–October. early emergent berry ber–October periods, no live-trapping was conducted species such as blueberries, Bunchberry, cur - (Obbard and Howe 2008), and fewer scats were found rant ( Ribes glandulosum ), raspberries, and Wild sar - on roads during this period, as some American Black saparilla dominated in July (Tables 1–2). Fruits eaten Bears had left the study area on foraging excursions in August were blueberries, Bunchberry, mountain-ash - (Obbard and kolenosky 1994). Of the 1023 scats, we es ,Pin cherry, raspberries, Bristly sarsaparilla, and Wild randomly chose 103 for analysis (Tables 1–2). sarsaparilla. The prominent fruit species in september– Amounts of green vegetation differed among months October scats were blueberries, Bunchberry, raspber - and years (Tables 1–3). During the may and June peri - ries, mountain-ashes, and Pin cherry. Beaked Hazelnut, ods, green vegetation was the major food component the only hard mast species found in the study area, was ingested; this decreased dramatically during July and an important food item in september–October. squash - August and increased again in september–October. berry (Viburnum edule ) was found in only one scat, The species of green vegetation that were prevalent, which was homogeneous for this single food item, thus expressed as percentage frequency of occurrence, were resulting in a high aggregate percentage mass (Tables ( Trifolium spp.), common Dandelion ( Tarax - 1–2). -leaved Buckthorn ( Rhamnus alnifolia ), acum officinale ), hawkweeds ( Hieracium spp.), horse - Three- solomon’s seal ( Maianthemum trifolia ), tails (Equisetum spp.), Trembling Aspen, and willows red-osier Dogwood ( Cornus stolonifera ), serviceber - (Table 4). Other items found in high frequency (though ries, and honeysuckles ( Lonicera spp.) were found in not mass) included seeds of Paper Birch, climbing low frequency. False Buckwheat ( Fallopia scandens ), and Tufted There was considerable variation among years in Vetch ( Vicia cracca ) (Table 4). some food items (Table 3). For example, a significant - The amount of grasses and sedges (Grass category) ly greater amount of blueberries was found in scats in in scats differed among periods (Tables 1–2), but not August 1991 than in the other two years (Figure 2). among years (Table 3). The main graminoids (Gram - Wild sarsaparilla was in greater abundance in August inae) eaten were Bluejoint reedgrass ( Calamagrostis of 1990 than in the other two years, and mountain-ashes canadensis ), Fowl mannagrass ( Glyceria striata ), and were in greater abundance in August 1992 than in the Quackgrass ( Elymus repens ). The primary sedges (cy - other two years (Figure 2). raspberries varied in fre - peracae) consisted of Tussock cottongrass ( Eriopho - quency of occurrence in August among years, but more rum vaginatum ssp . spissum ), Awl-fruit sedge ( Carex greatly in dry mass, with dry mass in 1992 being much stipata ), and various other Carex species. Other grasses lower than in the other two years. Bristly sarsaparilla and sedges found in very small amounts were Fringed was abundant in scats from August 1991, but was not

FiGUre 2. mean percentage dry mass (error bars show standard deviation) of berries that were found in American Black Bear scats ( n = 26) collected from the chapleau crown Game Preserve in August 1990–1992. Different superscripts indicate significant differences ( P ≤ 0.05) between years. 122 THe cANADiAN FieLD -N ATUrALisT Vol. 127 - e r ) r 7 2 P e

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9

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( 9 . ( ( ( ( ( ( (

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9 u

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1 0 0 0 0 0 0 4 0 ( (

9 ; m . . . . . ( (

( – – – – – – – – – – – – – – – –

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( – – – – – – – – – – – – – – – – – =

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v t s s s e t n t i k l m n b e s r d a u o u e a e i r i d h u i i o a a n o n n e n r r l t o a r e r u l e

V h L t i e q k s - d e m c m W H r B T P r A s s A B W B s D U B B G G A O B n o g a o A e o T G N V F 124 THe cANADiAN FieLD -N ATUrALisT Vol. 127

TABLe 3. Two-way analysis of variance (ANOVA) test statistics ( F values and P values) for comparisons of year (three lev - els—1990, 1991, 1992) and period (five levels—may, June, July, August, and september–October) main treatment effects, and their interaction (year • period), on dry mass of American Black Bear ( Ursus americanus ) food items from scats ( n = 103) examined from the chapleau crown Game Preserve, Ontario. P-values in bold were significant at a = 0.05. Food item year Period year • Period FP FP FP Vegetative items Green vegetation 3.33 0.040 37.90 0.001 0.73 0.647 Grasses 0.80 0.451 8.51 0.001 0.24 0.975 Alder-leaved Buckthorn 1.33 0.270 1.23 0.303 1.36 0.231 Beaked Hazelnut 0.93 0.397 2.05 0.094 0.83 0.564 Blueberries 4.19 0.018 4.08 0.005 2.15 0.047 Bunchberry 0.03 0.969 2.00 0.101 1.34 0.239 common strawberry 0.60 0.549 0.75 0.564 1.46 0.193 Honeysuckles 1.62 0.204 1.13 0.349 0.70 0.671 mountain-ashes 6.12 0.003 3.32 0.014 2.38 0.028 Pin cherry 1.56 0.216 1.66 0.167 0.66 0.704 raspberries 2.92 0.059 6.23 0.001 1.36 0.232 red-oiser Dogwood 0.51 0.600 1.01 0.407 1.40 0.218 serviceberries 0.15 0.862 1.71 0.155 0.94 0.481 skunk currant 2.05 0.135 1.56 0.193 1.16 0.332 squashberry 0.85 0.432 1.52 0.204 0.84 0.555 Bristly sarsaparilla 2.30 0.107 1.84 0.128 1.64 0.135 Wild sarsaparilla 10.71 0.001 14.06 0.001 9.39 0.001 Three-leaved False solomon’s seal 0.61 0.543 1.38 0.246 0.69 0.684 Non-Vegetative items Ants 0.46 0.631 17.25 0.000 1.92 0.075 Wasps 1.51 0.226 4.22 0.004 0.86 0.541 Animal 1.28 0.283 1.77 0.141 2.43 0.025 Debris 1.59 0.211 5.58 0.001 0.97 0.458 Unknown 0.46 0.633 1.41 0.238 3.47 0.003 Other 2.07 0.133 0.28 0.891 1.24 0.290 found in August scats from 1990 or 1992 (it was found able matches or because the items were too small and in some scats from september–October in 1992). too well digested to be recognized. The Other category The mass of ants (Formicidae) in scats varied among consisted of insects such as beetles (coleoptera), larvae, periods (Table 3). Ants were found in scats throughout roots, and snails. These were likely accidentally ingest - the sampling periods, but were found in very high fre - ed, or, in the case of larvae and snails, they may have quency in scats from June and July each year (Tables appeared on the scat after it was deposited. 1–2). scats contained adult ants, pupae, and larvae in association with large amounts of wood chips. The Discussion mass of wasps (Vespidae) varied among periods but not General results of our study are similar to those of among years (Table 3). Wasps were a consistent food other studies of American Black Bear food habits source that appeared in scats from June through sep - (Tisch 1961; irwin and Hammond 1985; Holcroft and tember–October, but were most prevalent in August Herrero 1991; Boileau et al. 1994), in which green veg - (Tables 1–2). etation and grasses comprised the bulk of diets in the We found significant interactions between year and spring and soft fruits and hard mast became the major period for Wild sarsaparilla, blueberries, mountain- constituents of the diet in summer and fall. However, ashes, animal, and the unknown category (Table 3). our study highlights the importance of summer soft mammal, , and fish remains were found in 15 mast crops to American Black Bears in the boreal for - different scats (15% of total) (Table 4). snowshoe est and shows the great variation that can occur in these (Lepus americanus ) (4 scats), American Beaver ( Castor crops among years. For example, 1990 was an average canadensis ) (3 scats), and ( Alces americanus ) year in terms of vegetation emergence and development (2 scats) were the most often consumed. in our study area, whereas in 1991 and 1992 vegeta - Unidentifiable bird remains were found in 4 scats. One tion emerged early (Usui et al. 2005). Frosts in late scat contained remnants of a variety of mammals along may 1992 destroyed most of the on the early- with fish scales and bones (Table 4). flowering berry species such as early Lowbush Blue - The Unknown component consisted of items which berry and raspberries (chapleau station: 25 may 1992 could not be identified, either because we found no suit - minimum air temperature -4.5°c, 26 may 1992 mini - 2013 rOmAiN eT AL .: B OreAL FOresT BLAck BeAr FOOD HABiTs 125 . s t 3 o a s 0 n t

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* l o T w * * A P F 126 THe cANADiAN FieLD -N ATUrALisT Vol. 127

mum air temperature -2.5°c; environment canada the proportion of adult ants in scats is likely higher 2013) and had a major impact on the berry crop (Usui than the proportion in ingested material (compared to et al. 2005). early Lowbush Blueberry fruits were fully larvae, which are presumably highly digestible) (Hatler ripened in the third week of July 1991, but no blueber - 1972; Landers et al. 1979; Boileau et al. 1994). Larvae ry fruits were available until the second week of August and pupae would be expected to be the target of ant in 1992, when Velvet-leaved Blueberry became avail - nest raiding due to their high energy and protein con - able. Velvet-leaved Blueberry generally flowers 2–3 tent and high digestibility (Noyce et al. 1997). Wasps weeks after early Lowbush Blueberry , so it was not increased in frequency in scats about the time that ants affected by the late frost in 1992. Further, a cool sum - were declining in frequency in July and August. Other mer resulted in later ripening of other berry crops in studies have reported wasps to be a component of the 1992 (chapleau station: average daily temperature in diet in late summer or fall (Hatler 1972; irwin and July 1992 was 13.7°c compared to 16.6°c in July 1990 Hammond 1985; Holcroft and Herrero 1991). and 16.9°c in July 1991; environment canada 2013). mammal, fish, and bird remains were found in 15% korschgen (1980) and mcLellan and Hovey (1995) of scats in this study. The most common species were suggested that more than two years of data are neces - , American Beaver, and moose, similar sary for food habits studies when annual fluctuations to the pattern reported by Holcroft and Herrero (1991) and trends are being described. results from our study and smith et al. (1994). Animal matter was found in support this view, as they showed distinctly different variable amounts and frequency throughout the for - patterns across three years, particularly in the late sum - aging period, although, unlike other studies (e.g., mer, when berries were the major food item. schwartz and Franzmann 1991), we did not detect coin - Seasonal variation cidental consumption of moose calves during the calv - Green vegetation was the most abundant food item ing season. schwartz and Franzmann (1991) observed in American Black Bear diets in may and June, and radio-collared calves being killed by American Black consisted predominantly of clovers, common Dande - Bears, but the low frequency of occurrence of moose , hawkweeds, Trembling Aspen, and willows (Table re mains in scats in their study confirms the high diges - 4). All of these species have been reported previously ti bil ity of animal matter (Gamberg and Atkinson 1988). (Tisch 1961; raine and kansas 1990; schwartz and The amount of remains left in scats likely Franzmann 1991; Boileau et al. 1994), although with underestimates the occurrence of these food items in less prevalence than in our study, suggesting that these the diet (Putman 1984; Pritchard and robbins 1990) species are more important spring foods for American due to their high digestibility. As such, bone and hair Black Bears in the boreal forest. clovers, common are typically the only components remaining in scats, Dandelion, and hawkweeds were mostly associated although these too may be substantially degraded with disturbed areas, such as recent clear-cuts, road - (Gamberg and Atkinson 1988). in addition, American sides, and roadside gravel borrow pits, and Trembling Black Bears typically remove the hide of ungulate prey Aspen and willows were common in regenerating clear- prior to consumption (Austin et al. 1994), so there cuts. would be even less likelihood of finding hairs from Grasses (Grenfell and Brody 1983; irwin and Ham - young moose calves in the scats of American Black mond 1985; schwartz and Franzmann 1991) and horse - Bears. tails (Hatler 1972; raine and kansas 1990) are the There is anecdotal evidence that American Black dominant food items reported for spring and early sum - Bears in the study area prey on moose calves (Obbard mer foraging periods in other studies. in this study, et al. 2000) and even on adult moose (Austin et al. grasses were found in the majority of scats, but only a 1994). However, it is unknown how commonly such few scats contained a homogeneous amount. The pro - events occur. By comparison, American Black Bears portion of grasses in scats is higher than the proportion preyed on 11.4% (5 of 44) of radio-collared moose of grasses in ingested material, since the high cellulose calves in a study in Algonquin Provincial Park (Pat - content results in poor digestibility (Grenfell and Brody terson et al. 2013), a protected area with American 1983), whereas succulent forbs are more easily digest - Black Bear density similar to that in the chapleau ed. Nevertheless, in our study, grasses were exploited crown Game Preserve (Howe et al. 2013). Dew claws throughout the spring, summer, and fall foraging peri - of moose calves and other remains were occasionally ods. observed in scats of live-trapped American Black Bears Ants were both frequent and abundant in scats dur - during the current study (meO, unpublished data); ing June and July and formed a large proportion of however, under the protocol of our study these par - the diet before the onset of the berry season, a pattern ticular scats were not randomly selected for analysis. also reported by others (irwin and Hammond 1985; more intensive sampling may be required to detect con - Holcroft and Herrero 1991; kasbohm et al. 1995; sumption of moose calves by scat analysis. Noyce et al. 1997). Because of the chitinous exoskele - The high incidence of American Beaver remains in ton of ants, the digestibility of adult ants is likely lim - fall scats suggests that American Beavers may be more ited. This can introduce bias into scat studies since vulnerable to by American Black Bears at 2013 rOmAiN eT AL .: B OreAL FOresT BLAck BeAr FOOD HABiTs 127

this time, perhaps because American Beavers are har - in adult female American Black Bears looking for vesting winter food supplies and building food piles anthropogenic sources of food and becoming more (Novak 1987). One scat contained remains of a vari - prone to come into conflict with humans (Howe et al. ety of mammal species as well as fish scales and bones. 2010). it is possible that an American Black Bear ingested The greatest variation in amount and frequency of part or all of a red ( Vulpes vulpes ) or other small occurrence of berry species among years occurred in carnivore that had remnants of the various prey in its the August and september–October periods. There was own gut contents. a significant interaction effect among period and year spawning runs of White sucker ( Catostomus com - for blueberries, Wild sarsaparilla, and mountain-ashes. mersonii ) were visited by American Black Bears in the For example, blueberries were fully ripened in early study area in spring each year (ca. 15–30 may) (meO, July in 1990, not until the third week of July in 1991, unpublished data). some American Black Bears con - and not until the second week of August in 1992. The gregated at these creeks, and spawning fish were appar - berries of mountain-ashes were significantly more ently a substantial food source, as various components abun dant than other berry crops in August 1992, where - (head, tail, lateral muscle, gut, and combinations of as blueberries were significantly more abundant in 1991 these) were missing from carcasses found adjacent to and Wild sarsaparilla was more abundant in 1990. The the creeks (DAr, personal observation). However, not increased availability of the berries of mountain-ashes all American Black Bears had such creeks within their in 1992 may have compensated for the loss of the ear - home ranges, and no fish remains were found in the ly Lowbush Blueberry crop due to the killing frost scats, which were collected at the time and randomly which seriously damaged the flowers in the spring that selected for analysis. it appears that our sampling re - year. The later flowering species, Velvet-leaved Blue - gime was adequate to describe consumption patterns berry , was little affected by the late frost and was the of most food items, especially the important fruit crops, species available by mid-August that year. but was insufficient to detect rarely consumed or sea - The variation in abundance of berry species in the sonally highly restricted food items. september–October period suggests that Beaked - The peak of the soft mast season in scats was in , Bunchberry, mountain-ashes, and Pin cherry were August, following the increase of early maturing all exploited to a greater extent in 1992 than in 1990 or species such as strawberries ( Fragaria spp.), skunk 1991, further emphasizing how the availability of food currant, Wild sarsaparilla, raspberries, blueberries, crops for American Black Bears can vary among years, and serviceberries in July and the persistence of some that other food crops may compensate if one food crop species (raspberries, blueberries) and appearance of fails, and emphasizing that American Black Bears must later maturing species, such as Alder-leaved Buck - be adaptable to be able to forage opportunistically. Fruit thorn, Bunchberry, Pin cherry, red-osier Dogwood, production in species such as mountain-ashes and Pin and Bristly sarsaparilla. Later maturing species, such cherry is strongly influenced by fruit production in the as Beaked Hazelnut, squashberry, and mountain-ash - prior year, often resulting in an alternating pattern of es, were found in scats in september and October. high and low fruit abundance in consecutive years Variation among years (Howe et al. 2012), again emphasizing that American We showed that American Black Bear food habits Black Bears must be adaptable and forage opportunis - determined by scat analysis were similar during the tically. spring season over the three years but differed during Two scenarios have been proposed to explain the the summer and fall seasons. This suggests that spring effect of food crops on American Black Bear popula - foods in the boreal forest do not differ greatly in abun - tions. The first is that berry use is limited to a major dance among years and so are predictable. in con - crop that ultimately regulates population recruitment trast, summer and fall foods vary greatly in abundance rates (Jonkel and cowan 1971; Landers et al. 1979; among years, and their abundance likely cannot be Beeman and Pelton 1980; rogers 1987; elowe and predicted by American Black Bears. Dodge 1989). The alternative explanation is that Amer - The breeding season for American Black Bears in ican Black Bears use a variety of major berry and mast Ontario mainly occurs before summer berry crops are crops, and switch to alternate foods during times of available (kolenosky 1990), and American Black Bears crop failure (kasbohm et al. 1996). results of this study exhibit delayed implantation (Hamlett 1935), meaning suggest that American Black Bears in the boreal forest that female American Black Bears that are available to will switch to alternate foods when a certain crop fails. mate are pregnant prior to the appearance of summer A diversity of soft mast producing species can pro - and fall food crops (even though blastocysts have not mote stability if different species are productive in dif - implanted). if females do not gain sufficient body mass ferent years (Garshelis and Noyce 2008), and a greater prior to late fall, implantation does not occur, and those overall diversity of mast species can provide demo - females do not produce a litter; this can affect lifetime graphic stability (Benson and chamberlain 2006). reproductive success. As a result, the energetic demands However, a long-term demographic study of the popu - of reproduction during years of food failure can result lation of American Black Bears in the chapleau crown 128 THe cANADiAN FieLD -N ATUrALisT Vol. 127

Game Preserve showed that cub survival was lower Documents Cited (marked * in text) during years of food shortages (such as 1992) and litter Adorjan, A. S., and G. B. Kolenosky. 1969. A manual for production rate was lower in years immediately follow - the identification of hairs of selected Ontario mammals. ing food shortages (Obbard and Howe 2008). There - research report (Wildlife) No. 90. research Branch, On- fore, in the boreal forest zone of Ontario, where few tario Department of Lands and Forests, maple, Ontario. alternate food crops are available and there can be con - 64 pages. Brunton, D. 1982. A reconnaissance life science inventory siderable annual variation in blueberry production (Usui of missinaibi Provincial Park. Pages 67 –77 in chapleau et al. 2005), American Black Bears may not always be crown Game Preserve management Plan: 1985 –2000. On - able to compensate for the loss of the blueberry crop. tario ministry of Natural resources, chapleau, Ontario. This could occur, for example, if a failure of the blue - McLaren, M., L. Dix Gibson, T. Armstrong, N. Dawson, berry crop happened to coincide with a low production M. Obbard, L. Landriault, M. de Almeida, P. Dodwell, year for alternate crops such as Pin cherry and moun - R. Black, G. Martin, and B. Radford. 2009. An approach tain-ashes. Understanding how summer food items vary to assessment of harvested black bear populations in On- in timing and abundance can help wildlife managers tario. southern science and information section Technical better understand the origins of patterns of human–bear report No. 127. Ontario ministry of Natural resources, southern science and information section, Bracebridge, conflicts in the boreal forest, and can provide insights Ontario. 31 pages. into demographic patterns and variation in harvest lev - Ontario Ministry of Natural Resources . 1984. chapleau els of American Black Bears and population structure. crown Game Preserve management Plan: 1985–2000. Un- monitoring the abundance of important food species published report, Ontario ministry of Natural resources, for American Black Bears on an annual basis would chapleau, Ontario. 94 pages. provide the information necessary to test hypotheses generated by these relationships. Literature Cited Forestry practices in the boreal forest can have a Austin, M. A., M. E. Obbard, and G. B. Kolenosky. 1994. positive effect on the abundance of foods consumed by evidence for a black bear, Ursus americanus , killing an American Black Bears, because these species in crease adult moose, Alces alces . canadian Field-Naturalist 108: in abundance in young regenerating forest stands (Bro - 236–238. Baldwin, K. A., and R. A. Sims. 1989. Field guide to the com - deur et al. 2008). early successional areas containing mon forest plants in northwestern Ontario. Ontario ministry species such as clovers, common Dandelion, Trem - of Natural resources, Thunder Bay, Ontario. 344 pages. bling Aspen, and willows are important foraging areas Beeman, L. E., and M. R. Pelton. 1980. seasonal foods and for American Black Bears in the boreal forest in the feeding ecology of black bears in the smoky mountains. spring. in addition, open areas created by wildfire or international conference on Bear research and manage - timber harvesting, especially where Jack Pine is pre - ment 3: 141–151. dominant in the overstory, are important foraging areas Benson, J. F., and M. J. Chamberlain. 2006. Food habits of in summer, when American Black Bears feed on spe - Louisiana black bears ( Ursus americanus luteolus ) in two cies such as blueberries, serviceberries, and Bristly subpopulations of the Tensas river Basin. American mid - land Naturalist 156: 118–127. sarsaparilla. Because the abundance of such food items Bland, R. G. 1958. How to know the insects. Third edition. varies among years and our study showed that they are Wm. c. Brown company, Dubuque, iowa. 409 pages. important food items in the diet of American Black Boileau, F., M. Crête, and J. Huot. 1994. Food habits of the Bears in the boreal forest, cutover areas or regenerat - Black Bear, Ursus americanus , and habitat use in Gaspésie ing burns should be protected from the application of Park, eastern Québec. canadian Field-Naturalist 108: 162– herbicides, which can cause a major reduction in fruit 169. production by species such as Vaccinium (moola et al. Brodeur, V., J.-P. Ouellet, R. Courtois, and D. Fortin. 2008. 1998). Habitat selection by black bears in an intensively logged boreal forest. canadian Journal of Zoology 86: 1307– 1316. Acknowledgements Brown, L. 1979. Grasses: an identification guide. Houghton support for field work and a graduate student stipend mifflin company, New york, New york. 240 pages. for DAr were provided by the Wildlife research and Czetwertynski, S. M., M. S. Boyce, and F. K. Schmiegelow. Development section, Ontario ministry of Natural re - 2007. effects of hunting on demographic parameters of sources. We thank the many people involved with the American black bears. Ursus 18: 1–18. Boreal Black Bear ecology project based near chap - Elowe, K. D., and W. E. Dodge. 1989. Factors affecting black leau, Ontario, who participated in the study. s. Hol - bear reproductive success and cub survival. Journal of lings worth helped with scat analysis and c. Lacroix Wildlife management 53: 962–968. assisted with identification of plant and seed samples. Environment Canada. 2013. climate data online. National climate Data and information Archive. http://climate.wea W. szkotnicki provided statistical advice. We thank theroffice.gc.ca/climateData/canada_e.html . Accessed 29 L. caston, s. Fava, r. Gurure, e. Howe, T. Jung, G. June 2013. kolenosky, T. Nudds, D. Potter, and two anonymous Gamberg, M., and J. L. Atkinson. 1988. Prey hair and bone reviewers for advice and comments on earlier versions recovery in ermine scats. Journal of Wildlife management of the manuscript. 52: 657–660. 2013 rOmAiN eT AL .: B OreAL FOresT BLAck BeAr FOOD HABiTs 129

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