Excavation of Red Squirrel ( Tamiasciurus hudsonicus ) Middens by Bears ( Ursus spp.) in Limber ( Pinus flexilis ) Habitat in Banff National Park,

DAviD HAMER

300–379 Spring Creek Drive, Canmore, Alberta T1W 0G8 ; email: [email protected]

Hamer, David. 2016. Excavation of Red Squirrel ( Tamiasciurus hudsonicus ) middens by bears ( Ursus spp.) in Limber Pine ( Pinus flexilis ) habitat in Banff National Park, Alberta. Canadian Field-Naturalist 130(4): 281–288. Bears ( Ursus spp.) in eat the seeds of several ( Pinus spp.), including Limber Pine ( P. flexilis E. James). information on use of Limber Pine in Canada is limited to a report of three bear scats containing pine seeds found in Limber Pine stands of southwestern Alberta. After my preliminary fieldwork in Banff National Park revealed that bears were eating seeds of Limber Pine there, i conducted a field study in 2014–2015 to assess this use. Because bears typically obtain pine seeds from cone caches (middens) made by Red Squirrels ( Tamiasciurus hudsonicus ), i described the abundance, habitat characteristics, and use by bears of Red Squirrel middens in and adjacent to Limber Pine stands at six study sites. On Bow River escarpments, i found abundant Limber Pines (basal area 1–9 m 2/ha) and middens (0.8 middens/ha, standard deviation [SD] 0.2). Of 24 middens, 13 (54%) had been excavated by bears, and three bear scats composed of pine seeds were found beside middens. Although Limber Pines occurred on steep, xeric, windswept slopes (mean 28°, SD 3), middens occurred on moderate slopes (mean 12°, SD 3) in escarpment gullies and at the toe of slopes in forests of other species, particularly Douglas-fir ( Pseudotsuga menziesii ). At the five other study sites, i found little or no use of Limber Pine seeds by bears, suggesting that Limber Pine habitat may be little used by bears unless the pines are interspersed with (non-Limber Pine) habitat with greater forest cover and less-steep slopes where squirrels establish middens. These observations provide managers with an additional piece of information regarding potential drivers of bear activity in the human-dominated landscape of Banff National Park’s lower Bow valley. Key Words: ; Banff National Park; Grizzly Bear; Limber Pine; midden; Pinus flexilis ; Red Squirrel; seeds; Tamiasciurus hudsonicus ; Ursus americanus ; Ursus arctos Introduction 1983; Schwartz et al. 2006; Fortin et al. 2013). As stated Seeds of the genus Pinus () are eaten by Asi - by Mattson and Reinhart (1997: 926), when Whitebark atic Black Bears ( Ursus thibetanus ), American Black Pine seeds are abundant, Grizzly Bears in Yellowstone Bears ( U. americanus ), and Grizzly-Brown Bears ( U. “eat virtually nothing else”. Whitebark Pine seeds are arctos ; Mattson and Jonkel 1990). Pine seeds range in nutrient and energy rich, containing approximately 21% weight from < 5 mg for Jack Pine ( P. banksiana Lam - protein, 21% carbohydrate, and 52% lipids, exclusive bert) and Lodgepole Pine ( P. contorta Douglas ex Lou - of the seed coat (Tomback et al. 2001). don) to the 900-mg seed of Torrey Pine ( P. torreyana Limber Pines are also common in the Yellowstone Parry ex Carrière ; Tomback and Linhart 1990). How - ecosystem, but Kendall (1983) did not find evidence ever, only large pine seeds (≥ 90 mg) are known to be that Yellowstone bears ate their seeds. Limber Pine eaten by bears. in North America, bears eat the 240-mg stands appeared to support few if any Red Squirrels, seeds of Pinyon ( P. edulis (Engelm.) ; Costel - and Kendall found neither claw marks nor broken lo et al. 2001, 2003), the 175-mg seeds of Whitebark branch es on Limber Pine to suggest that bears Pine ( P. albicaulis (Engelm.) ; Kendall 1983), the 170- were harvesting cones directly from trees. However, mg seeds of Southwestern White Pine ( P. strobiformis McCutchen (1996) found that some American Black (Engelm.); Mattson and Arundel 2013), the 120-mg Bears, in some years, fed intensively on Limber Pine seeds of Jeffrey Pine ( P. jeffreyi (Balf.) ; Kuhn and van - seeds obtained from Red Squirrel middens in Rocky der Wall 2007), and the 90-mg seeds of Limber Pine Mountain National Park, Colorado. (P. flexilis E. James ; McCutchen 1996; seed sizes from in Alberta, a Limber Pine survey during 1995–1996 Tomback and Linhart 1990). Of these, only Whitebark recorded three bear scats containing pine seeds in Lim - Pine and Limber Pine extend into the northern United ber Pine stands: two in Waterton Lakes National Park States and Canada; the other three species occur in the and the third in the Porcupine Hills, roughly 50 km southwestern . north of Waterton Lakes National Park (United States in the Yellowstone ecosystem, bears obtain White - Department of the interior and United States Geologi - bark Pine seeds from caches of cones (middens) made cal Survey 2012). Many Limber Pines at these locations by Red Squirrels ( Tamiasciurus hudsonicus ; Kendall were short enough that bears could have obtained cones

A contribution towards the cost of this publication has been provided by the Thomas Manning Memorial Fund of the Ottawa Field-Naturalist’s Club. 281 ©The Ottawa Field-Naturalists’ Club (2016) 282 THE CANADiAN FiELD -N ATURALiST vol. 130

directly from trees. The species of bear was unknown; imity to Whitebark Pine in upper-elevation, windswept this was a brief survey as part of a study on pine stand sites in the park. However, Limber Pine extends farther health. east into portions of the Front Ranges where White - in Banff National Park, both American Black Bears bark Pine is absent. and Grizzly Bears are known to eat Whitebark Pine Corns and Achuff (1982: 105) described a specific seeds (Raine and Kansas 1990; Hamer and Pengelly Limber Pine–Douglas-fir/Juniper ( Juniperus spp.)/ 2015). However, to my knowledge, there are no records Common Bearberry ( uva-ursi ) open- of bears eating the seeds of Limber Pine in Banff Na - forest vegetation type (type O2) in Banff National Park. tional Park. During preliminary fieldwork in 2014, i it is found on rapidly drained, moderately to steeply determined that bears were eating Limber Pine seeds sloped, south-facing erosional escarpments along the and i therefore studied Limber Pine in and near Banff lower Bow and North Saskatchewan rivers, in habitat National Park during 2014–2015 to assess this use and that is among the warmest and driest in the park. These describe the habitat where bears obtain Limber Pine escarpments are composed of glacial till, unconsoli - seeds. Limber Pines in Banff National Park are tall, dated material that is frequently eroded, resulting in up right trees, and i assumed that if bears fed on their exposed till and substantial gullying. seeds, they likely would obtain them from Red Squir - rel cone caches, as reported in Rocky Mountain Nation - Methods al Park (McCutchen 1996) and as reported for White - i searched Limber Pine habitat to determine the den - bark Pine (Mattson and Reinhart 1997; Hamer and sity and use by bears of Red Squirrel middens, i.e., lo - Pengelly 2015). Thus, my principal objective was to cations where squirrels cache large numbers of coni- record the abundance, habitat characteristics, and use fer cones, shred these cones to obtain seeds, and create by bears of Red Squirrel middens in and adjacent to conspicuous deposits of organic material (Gurnell 1984). Limber Pine stands. i also examined Limber Pine trees for broken branch - es, claw marks, or crushed cones on the ground that Study Area could indicate that bears were obtaining cones directly Banff National Park extends eastward from the Con - from trees. tinental Divide and, thus, is in a rain shadow with re - i established six study sites based on local knowl - spect to the prevailing westerly winds (Holland et al. edge of Limber Pine stands. Four (A, B, D, E) were in 1982). The park includes Main Range and Front Range Banff National Park: three (A, D, E) in the main Bow habitat of the , but does not extend valley between the east park boundary and the begin - eastward into the Alberta Foothills. Warm, drying adi - ning of the Bow valley Parkway and one (B) near the abatic winds (Chinooks) frequently descend the east icefields Parkway crossing of the North Saskatchewan slopes of the Rocky Mountains. These winds contribute River. The Red Deer River site (C) was less than 1 km to the rain shadow effect and to the development of east of the park boundary; and F was 21 km east of xeric, non-forested balds and open-forest communities the park in a narrow portion of the Bow valley that is below the line on south- and west-facing slopes subject to strong Chinook wind. Some Limber Pine (Achuff 1982; Hamer 1996). trees at site F were wind stunted and had cones within Limber Pine grows on dry, windswept sites, often in 0–2 m of the ground. shallow soils, and on steep, rocky sites and within cliff Methods differed among the six sites (Table 1). On bands (Steele 1990; Alberta Whitebark and Limber Pine river escarpments (sites A and B, Table 1), Limber Pines Recovery Team 2014). Limber Pine is relatively shade occurred in confined bands above the rivers. Thus, i intolerant (Steele 1990) and is commonly found in low- established 5–12 ha blocks in this linear habitat and density, open forests. in Banff National Park, Limber made total searches for Red Squirrel middens by walk - Pine occurs in the montane and lower subalpine, from ing on elevational contours at regular intervals within valley bottom to about 2000 m elevation, in the eastern, these blocks, such that my sightlines overlapped. When more xeric portions of the park. it typically grows on the topography was complex, i used the tracks function steep, south- and west-facing slopes with high exposure of a handheld Global Positioning System (GPS) unit to to the warming, drying influence of Chinook wind and ensure complete visual coverage. solar radiation. On the Bow River escarpment, i established four in Banff, Limber Pine is often found in open forests blocks of habitat where Limber Pines were abundant with Douglas-fir ( Pseudotsuga menziesii (Mirbel) Fran - (site A.1, Table 1). i fixed the four corners of each block co), a species that also tolerates warm, dry sites (vyse on a handheld GPS unit. The two upper corners were et al. 2006). Limber Pine is also found with White on the escarpment rim, separated by 300 m or 500 m Spruce ( Picea glauca (Moench) voss) at lower eleva - (horizontal map distances); the two lower corners were tions, interior Spruce ( P. engelmannii Parry ex Engel - located at the toe of the slope, similarly separated by mann var. engelmannii × P. glauca ) in the subalpine, 300 m or 500 m. Thus, block boundaries from rim to and Lodgepole Pine ( Douglas ex Lou - toe of slope were straight lines of variable length, don). Limber Pine occasionally grows in close prox - whereas upper and lower boundaries were fixed hori - 2016 HAMER : L iMBER PiNE SEEDS AS FOOD FOR BANFF BEARS 283

h zontal map distances, but followed the rim and toe of h c c r r a slope, respectively, and, hence, were irregular in shape. a h e e s c

s r l Blocks covered 5.2–9.7 ha. The mean horizontal dis - a l a e h t a

t s o

tance from rim to toe of slope was 226 m (standard 5 t o l

t ,

a

n , t s s s s i deviation [SD] 7, n = 4 blocks). t t t s

o k c t c c k d c

e e e , c e

o i established a 500-m long block where Limber Pines s s s l k o y l n n n c b e

a a a b o

v were most abundant. i then established three addition -

r r r a l r d t t t a

h b u o t t t

h - l l l s al blocks, each 300 m long, two downstream and one - h a

0 t e e e 8 h a 1 e . b b b - e

– upstream of the 500-m long block. Each block was sep - 1 r f f f 2

m 5

a o o o 1

e

r d e

a arated by 300 m of unsampled habitat. Blocks were l a a a e r u e h h h h n h i o

-

numbered consecutively from upstream to downstream. 6 F F T O 7 6 6 Limber Pine had low density beyond these blocks and was not sampled. i recorded coordinates for all Red Squirrel middens y y in each block with a handheld GPS unit to accurately r r s r r e e e t i locate middens near boundaries. in addition, i recorded b b n c r r a e a a s n p the presence of Limber Pine cones or cone scales, slope e e s i s

o y y B B r m r r

, , aspect and steepness, and basal area of trees using a r r m o o r r r r t r e e 2 e e e e d a e b b ) p p p p 2 m /ha prism, following the methods described by c r r - h i i i i i t a a o n n n n d a e e u u u u Hamer and Pengelly (2015). i examined middens for e C n J i J f ( B B J J evidence of excavation by bears. Because Limber Pine cones were 25 times more abundant in 2015 than 2014 (15 cones/tree in 2015 versus 0.6 cones/tree in 2014 on e n i e 10 permanently identified trees in site A.1), i re-exam - P e n

i c e e P u l ined all middens in late September 2015 for evidence

r n

o e i . p l p 5 P S o of excavation by bears. e

1 r p g e 0 e e t d

i Location of middens was facilitated by their large 2 b g o h – 2 2 d L m

4

i o t size (mean 39 m , range 11–92 m ; Figure 1). All mid - , W 1

n L L e e ,

0 a c c , , e den excavations were attributed to bears. Although few 2 r r r r s n u u

n i i i i i e , r r i f f f f i a - - - - p p P m c t scats were found at middens in this study, those found s s s s

r S S o e r a a a a

e l l l l d e p e e )

b were from bears. in addition, excavations did not differ s g g t t g g b l -

i i u u u u e o h h m A o o o o e i in appearance from those found in Whitebark Pine habi - , C r D t D W ( W L D D k

r tat, where abundant bear scats and radio-locations from a P

l collared bears were positively linked to excavated mid - a

n dens (Hamer and Pengelly 2015). Thus, there appears o i m 0 0 0 0 0 0 0

t ,

7 7 6 4 0 9 0 a to be no plausible alternative to bears being the source f n 5 4 4 4 8 6 6 o N o

1 1 1 1 1 1 1

i f e t of these excavations (Figure 1). This contention is fur - – – – – – – – f a g 0 0 0 0 0 0 0 n v n 8 6 4 0 7 2 6

a ther supported by observation that middens in habitat e a 3 3 4 4 6 5 4 l B 1 e 1 1 R 1 1 1 1

r lacking nearby Whitebark Pine or Limber Pine were not a e

t dug, including the 15 undug middens of upland site A .2 n

s d e

r and an additional nine middens (all undug) in a block n o a f

t t

n 300 m upstream of site A.1. This latter block was ex- n n d i e e

n s e e e a m m cluded from this report because no Limber Pines were e l d d d t i i i p p i p y n r r s s s s

a u h

a a recorded at either middens or systematic plots.

f n n n t p c c

y i i i l s s a n d a a a a r Because 79% of site A.1 middens occurred in gullies, e e t t t e i u

g t c n r r n n v s o a e e u u u

u

j i obtained additional information on gully character - p ) l v v o o o d l i i s o i l M T R A R A M M istics. i used trigonometry to calculate gully size at the i x

e midden by measuring slope distance with a steel tape l f n

a s and slope angle with a clinometer, from gully bottom u w e n i d

h to crest of gully side, at right angles to the run of the r e P c e t ( h e

a s gully at the midden. i averaged the heights of left and e r

k D h n

e t s i t r w w w w w d a right sides to obtain gully depth. a P o o o o e o o

S r B W B B N R B B

e To compare habitat characteristics at middens to b

m characteristics in the site as a whole, i recorded habi - i L

tat characteristics at 65-m intervals along linear tran - . 1 sects on fixed elevational contours within each block E L e B 1 2

t (systematic plots). in each block, i ran three parallel . . i A T S F A A B C D E transects spaced by 50 m of elevation. i varied starting 284 THE CANADiAN FiELD -N ATURALiST vol. 130

FiGURE 1. Red Squirrel ( Tamiasciurus hudsonicus ) cone cache or midden excavated by bears at site A.1 of the Bow River escarpment, adjacent to Limber Pine ( Pinus flexilis ) habitat, Banff National Park, Alberta, 2015. Photo: D. Hamer (10- second timer). distances on each transect so that systematic plots would helicopter-assisted field day. This survey was facilitated not lie directly upslope or downslope from each other. by the gentle slope and open, immature forest of thi s Because site A.1 was used intensively by bears, i also disturbed site, which provided easy travel and high vis - obtained comparative data from the gently sloping, up - ibility. However, because time was limited, i did not land forest at the top of the escarpment (site A.2, Table collect all data at middens, and i could not confidently 1) by establishing 300-m by 60-m irregularly shaped state that i had completed a total search. Systematic plots (i.e., following the lie of the escarpment rim), a d - plots were established at 80-m intervals along a linear joining blocks 2–4. Middens were recorded if they were transect running through the alluvial fan. within 60 m of the rim. Upland forest plots were not i established three mountain sites in the Bow valley established at block 1 nor along 200 m of the 500 m where Limber Pines occurred on steep slopes with length of block 2 because human activity had removed abundant rock outcrops (sites D–F, Table 1). These sites or highly modified the forest at those locations. were too extensive for total searches, as used on the At the North Saskatchewan River escarpment (site B, confined river banks of sites A and B and the alluvial Table 1), the distance from escarpment rim to river fan of site C; thus, i sampled them by running 20-m bottom was less than half that at the Bow River escarp - wide belt transects following procedures described by ment, and there was little gullying. Therefore, i searched Hamer and Pengelly (2015). i ran transects on eleva - one 1300-m long, 12-ha block where Limber Pines tional contours; 30-m belts were used in open habitat occurred, following the procedures described for site with higher visibility. i used a handheld GPS unit to A. Because of time constraints, i established systematic locate transects at regular vertical intervals on the slopes plots along only 650 m of the 1300-m block length, and to measure transect lengths. i located and described where Limber Pines were more abundant. all Red Squirrel middens that fell inside belt transects The Red Deer River site was an active alluvial fan (Hamer and Pengelly 2015). i also established compar - created by a stream discharging into the valley bottom ative systematic plots at 65–m intervals along the tran - of the main Red Deer River valley (site C, Table 1). i sects as described for escarpment blocks. spent 5 h surveying 7 ha of this alluvial fan during a 2016 HAMER : L iMBER PiNE SEEDS AS FOOD FOR BANFF BEARS 285 n

Results i

s s r e a

Bow River escarpment (site A) t e s i s b n

The mean basal area of Limber Pine in systematic e y y

2 d d b d

plots at the Bow River site was 9 m /ha in block 2 and 3 u i 2 0 0 0 1 1 t d

2 1 s e m

t 1–2 m /ha in the remaining three blocks. Of the 24 Red . x a i o v s

Squirrel middens examined in 2014 at this site (Table a N t c a

x t

2), bears had excavated 10 (42%). Bear scats composed e a t almost entirely of pine seed coats were found at three i b a h c middens. Re-examination in 2015 revealed that bears i l ) t ) ) l ) s ) ) ) ) a 4 ) 2 a i 8 4 5 8 had excavated 11 of the 24 middens (46%). Two that l D 1 4 1 i ( ( ( ( f m (

( (

S x

o e ( 8 7 7 0

t e

7 7 had been recorded as excavated during 2014 field work 5 l s a 2 1 1 1 a f 1 4 e y

h r s / were not excavated in 2015, but three other middens S a 2 u

l n m i a were. Hence, 13 different middens (54% of 24 middens) , s P s a ( r

b were excavated when 2014 and 2015 observations are ) n e

e ) ) ) f 9 e n n i 7 2 8 i 1 d ( ( ( a 6 8 combined. n (

d P e

6 — 4 o

i 7 4 4 6 r c 2 4 4 M

Five of the 24 middens (21%) were at the toe of the e 3 M b

slope; one had been excavated by bears. The remaining m i ) L D

c

19 middens were at the bottoms of gullies (mean gully i f n ) ) ) ) ) ) S t i ( o 0 7 0 0 0 0

a

......

width 42 m [SD 15, n = 4]; mean depth 7 m [SD 3, n = s a a t 4 0 4 4 0 4 5 m . h ( ( ( ( ( ( e o

/ e r l 0 t

4]). Mean slope steepness at the middens was less than 2 0 4 0 0 0 0 a p s ......

l m y 2 0 7 5 3 3

d half that at the systematic plots (Table 2). a , S e s e c a n a i Only one of the 24 midden sites contained Limber b l

P ) ) ) p n

n r 0 3 1 Pine, resulting in a mean basal area at middens of only a . . . y e e e l 4 0 0 0 0 0 0 l

2 d b . . . . ( ( ( a d

0.06 m /ha. However, mean basal areas of Douglas-fir, M 0 0 0 0 i c m 0 2 1 i i . . . t M 2 0 0 L

White Spruce, and Lodgepole Pine were 23 (SD 11), 11 a 2 m

(SD 4), and 8 (SD 6, n = 4) m /ha at the middens. The e t s y total basal area for all at the middens was more c i s

t t ) ) ) ) ) a ) ) ) than double that in the systematic plots (Table 2). a 9 6 6 3 8

1 3 ( ( ( ( ( m D

(

(

d

e e S 1 5 9 8 5 t Sixteen middens were located in upland White n ( 8 6 p s

a 3 2 2 2 2

o ° y s l

Spruce–feathermoss (e.g., Hylocomium splendens , t S s

s o s l n

(Hedw.) Schimp. in B.S.G. , Pleurozium schreberi e p a

n e n p n ) ) )

(Brid.) Mitt.) forest on the gently sloping bench land e M e ) e 5 4 3 d e 1 d ( ( ( 6 4 t d

(

d

i s 1 — adjacent to the escarpment (site A.2, Table 2). None 1 i 1 0 2 5 2 1 1 m was excavated by bears in 2014, but one was excavat - M ) s ed in 2015. Eleven of the upland middens (69%) con - u c i tained Limber Pine cones or cone scales. The nearest n o c i s ) ) ) ) ) t ) ) d 1 1 5 1 0 Limber Pines occurred on the rim of the escarpment. a 9 3 u 2 2 1 2 3 ( 4 ( (

( ( ( m ) h

(

2

e e 5 3 7 2 5 t s D 2 5

North Saskatchewan River escarpment (site B) s p 5 3 4 1 8 u S 1 2 y r o ( 1 2 1 2 2 1

l u S s The basal area of Limber Pine was 5 m /ha in the ° i

, c n t s a systematic plots on the North Saskatchewan escarp - c a e e i ) ) ) ) n p 3 5 3 m 5 e M ment (Table 2). One midden occurred on the open s 2 6 1 . 3 4 a 5 d a ( ( ( 5

(

1 4 T d

— ( i 1 6 3 0 2 slopes of the escarpment. Two were in the single gully 1

7 l 0 4 5 3 1 M e 2 1 1 2 that dissected the block, in White Spruce–feathermoss r – r i 4 u forest (total 0.2 middens/ha). Four middens were with - 1 , q 0 y t S 2 i in 60 m of the escarpment rim in adjacent upland White , s d a n e ) t e Spruce–Lodgepole Pine forest (0.9 middens/ha). All r R D ) ) d e

t 9 2 S b . . n a l seven middens contained Limber Pine cones or cone (

e 7 2 6 2 0 0 3 s . . . . . A a ( ( d

c , 0 0 0 0 0 h i scales; none was excavated by bears. d 0 8 / t i k . . . s r 3 0 o i m a r

n P Red Deer alluvial fan (site C) e n

t l a c a e in the Red Deer site, basal areas of Limber Pine, a n r M a 2 o i h White Spruce, and Lodgepole Pine were 7, 6, and 5 m / t c a

s t n N a ha, respectively, at systematic plots placed in the active . e t f i 6 4 o f d 4 1 4 3 2 b 1 2 n d

portion of the fan. No middens were located in this N a i a H m B

Limber Pine habitat. Four middens were located on the . r 2 a

eastern edge of the fan in an alluvially inactive zone e E n L

e B 2 1 d

where successionally mature White Spruce–feather - t . . i A n E D C B A A moss forest has developed; all contained Limber Pine T a S F 286 THE CANADiAN FiELD -N ATURALiST vol. 130

cones or cone scales but none was excavated by bears. further evidence that Limber Pine stands do not, in The mean distance from these middens to the nearest themselves, support bear use of Limber Pine seeds. Limber Pine was 75 m (range 46–95 m). These two sites had the highest basal areas of Limber Mountain sites (sites D-F) Pine of all sites, but i recorded only one midden and no Sites D–F had low Limber Pine basal area and low evidence of use of Limber Pine seeds by bears. Hence midden density (Table 2). Mean slope steepness at the i conclude that Limber Pine habitat tends to show min - middens was less than that at the systematic plots imal or no use by bears – unless the pines are inter - (Table 2). All middens contained Limber Pine cones or spersed with (non–Limber Pine) habitat with higher cone scales; two middens in site E and one midden in forest cover and lesser slope steepness where squir - site F had been excavated by bears. rels can establish middens, such as found at the Bow (Note added in proof: One excavated midden con - River escarpments. taining 48 Limber Pine cones and 57 Whitebark Pine The Red Deer alluvial fan differed from other sites in cones on its surface was discovered on 13 September having gentle slopes of less than 10° steepness. The 2016. it was located 6 m from a 16 October 2013 GPS coarse, rocky alluvium found at the surface of the active location of a collared adult female Grizzly Bear. This portion of this fan may have prevented squirrels from midden was less than 2 km from site E, at 2120 m ele - burying and caching cones, and thus may have had an vation, adjacent to a rocky ridge crest where both Lim - effect analogous to steep slope. ber Pine and Whitebark Pine are abundant [D. Hamer, Gurnell (1984) found that Red Squirrels moved 2016 field observations]). Lodgepole Pine cones as far as 185 m. However, i as - sume that the abundance of Limber Pine cones in mid - Discussion dens will decrease with increasing distance from Lim - My observations at the Bow River escarpment of ber Pine trees, and at some distance a lower number Red Squirrel middens excavated by bears and three of Limber Pine cones and seeds presumably will not bear scats composed of pine seed coats are, to my attract bears. For instance, none of the 16 middens in knowledge, the first record of bears in Banff National the upland White Spruce forest above the Bow River Park eating Limber Pine seeds. The species of bear escarpment but within 60 m of the escarpment rim was responsible for these field signs could not be deter - excavated by bears in 2014, although eleven of these mined, as both Grizzly and American Black Bears are middens contained Limber Pine cones or cone scales. common in this portion of the park. Species identifica - The abundance of Limber Pine cones may also explain tion could likely be achieved by DNA or remote cam - why some middens at the Bow River escarpments were era sampling. However, only three pine seed scats were excavated while others were not. For example, Limber located during this study and were unsuitable for DNA Pine was abundant in block 2 of this site (mean basal 2 analysis because of age; and use of cameras was pre - area at systematic plots, 9 m /ha), and all eight middens cluded. in this block were excavated in 2015. in contrast, Lim - The steep, windswept, open escarpment at the Bow ber Pine was less abundant in the other three blocks 2 River site was not used by Red Squirrels as midden (1–2 m /ha), and only three of the 16 middens at these locations. Rather, all 24 middens were either in gullies other locations were excavated in 2015. or at the toe of the slope, adjacent to steeper slopes Although the North Saskatchewan site was identified where Limber Pine trees occurred. Middens were on as a Limber Pine–Douglas-fir type by Corns and Achuff slopes that were less than half as steep and contained (1982), i did not find Douglas-fir at this site. Elevation more than twice the basal area as slopes where was the same as at the Bow River escarpment (1400 m, Limber Pines occurred. Limber Pines were similarly Table 1), but the North Saskatchewan is farther north absent from midden sites elsewhere in the study area. in a glaciated region of the park that includes the Wil - Eighteen of the 20 middens in sites B–F were in White son icefield 5 km north of my study area. At the North Spruce, Lodgepole Pine, and/or Douglas-fir forests, Saskatchewan site, the lack of Douglas-fir and the pres - where Limber Pine measured zero in basal area. Ken - ence of only one forested gully to provide suitable food dall (1983) found a similar pattern in Yellowstone Na - and shelter for Red Squirrels in close proximity to Lim - tional Park: no Red Squirrel middens occurred within ber Pine trees may explain why midden density was her three Limber Pine study areas. it appears that Lim - only a quarter of that found at the Bow escarpments and ber Pine stands, typically, are not Red Squirrel habitat also why bears apparently did not eat Limber Pine and, hence, are less likely to be sites where bears obtain seeds at the North Saskatchewan escarpment. pine seeds. On the Bow River escarpment, however, No field signs were found to indicate that bears were frequent small gullies provide Red Squirrel habitat in harvesting cones directly from Limber Pine trees. Al - close (< 100 m) proximity to Limber Pine stands, and though Banff National Park is subject to frequent Chi - my observations in 2014 and 2015 suggest that bears nook winds, the trees are not stunted as they are in regularly eat the seeds of Limber Pine at this location. Waterton Lakes National Park or the Porcupine Hills of Observations from the North Saskatchewan River southwestern Alberta, where Alberta’s strongest Chi - escarpment and Red Deer River alluvial fan provided nook winds occur (vickers et al. 2001). Thus, cones 2016 HAMER : L iMBER PiNE SEEDS AS FOOD FOR BANFF BEARS 287

were not within reach of bears on the ground except at Costello, C. M., D. E. Jones, R. M. Inman, K. H. Inman, B. site F, which also lacked evidence that bears had har - C. Thompson, and H. B. Quigley. 2003. Relationship of vested cones from trees. variable mast production to American black bear repro - The Bow River valley has been described as one of ductive parameters in . Ursus 14: 1–16. Fortin, J. K., C. C. Schwartz, K. A. Gunther, J. E. Teisberg, the most human-dominated landscapes where Grizzly M. A. Haroldson, M. A. Evans, and C. T. Robbins. 2013. Bears still survive (Gibeau et al. 2001). Hebblewhite Dietary adjustability of grizzly bears and American black et al. (2003) found that 82% of American Black Bear bears in Yellowstone National Park. Journal of Wildlife mortality in the Bow valley is caused by humans. The Management 77: 270–281. Bow valley escarpment, where i observed substantial Gibeau, M. L., S. Herrero, B. N. McLellan, and J. G. use of Limber Pine seeds by bears, is within 3 km of a Woods. 2001. Managing for grizzly bear security areas town of roughly 10 000 people, the four-lane Trans- in Banff National Park and the central Canadian Rocky Canada Highway, the Canadian Pacific Railway main Mountains. Ursus 12: 121–130. line, and an 800-unit campground. The escarpment is Gurnell, J. 1984. Home range, territoriality, caching behavior and food supply of the red squirrel ( Tamiasciurus hudson - also traversed by a network of walking and bicycling icus fremonti ) in a subalpine lodgepole pine forest. Animal trails and undesignated paths. Behavior 32: 1119–1131. Managers should consider use of Limber Pine seeds Hamer, D. 1996. Buffaloberry [ Shepherdia canadensis (L.) by bears in the Bow River escarpment if they choose to Nutt.] fruit production in fire successional bear feeding mitigate soil erosion and other impact from the profu - sites. Journal of Range Management 49: 520–529. sion of paths that currently dissect the unique and frag - Hamer, D., and I. Pengelly. 2015. Whitebark Pine ( Pinus albi - ile habitat of the Bow River escarpment. Continued caulis ) seeds as food for bears ( Ursus spp.) in Banff Nation - evaluation of bear use of Limber Pine seeds may also al Park, Alberta. Canadian Field-Naturalist 129: 8–14. benefit management of Limber Pine throughout Alber - Hebblewhite, M., M. Percy, and R. Serrouya. 2003. Black bear ( Ursus americanus ) survival and demography in the ta, where this tree species is listed as endangered (Al - Bow valley of Banff National Park, Alberta. Biological berta Whitebark and Limber Pine Recovery Team 2014). Conservation 112: 415–425. Holland, W. D., P. L. Achuff, and B. D. Walker. 1982. Cli - Acknowledgements mate. Pages 4–12 in Ecological (Biophysical) Land Classi - i thank Parks Canada’s Banff National Park Re - fication of Banff and Jasper National Parks. volume ii: Soil source Conservation Service, Banff Field Unit, for sup - and vegetation Resources. Publication SS-82-44. Edited by port. ian Pengelly made numerous suggestions, direct - W. D. Holland and G. M. Coen. Alberta institute of Pedol - ed me to several Limber Pine stands, and reviewed the ogy, Edmonton, Alberta, Canada. manuscript. i also thank M. Bernauer, B. Gleig, D. Kendall, K. C. 1983. Use of pine nuts by grizzly and black bears in the Yellowstone area. international Conference on Gummer, R. Osiowy, J. Park, J. Whittington, and N. Bear Research and Management 5: 166–173. Woode for assistance, and two anonymous reviewers Kuhn, K. M., and S. B. Vander Wall. 2007. Black bears and the editors for useful comments on the manuscript. (Ursus americanus ) harvest Jeffrey Pine ( Pinus jeffreyi ) seeds from tree canopies. 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