Observations of American Marten (Martes americana) Feeding
at Sap Wells of Yellow-bellied Sapsuckers (Sphyrapicus varius)
Hugo Kitching and Douglas C. Tozer
Northeastern Naturalist, Volume 17, Issue 2 (2010): 333–336
Full-text pdf (Accessible only to subscribers.To subscribe click here.)
Access Journal Content
Open access browsing of table of contents and abstract pages. Full text pdfs available for download for subscribers.
Current Issue: Vol. 30 (3)
Check out NENA's latest Monograph:
Monograph 22
Observations of American Marten (Martes americana) Feeding
at Sap Wells of Yellow-bellied Sapsuckers (Sphyrapicus varius)
Hugo Kitching1 and Douglas C. Tozer2,*
Abstract - Martes americana (American Marten) is reported to eat a diverse diet, including
mammals, invertebrates, and plants. Despite this variety, we found no reference to tree sap in
its diet. Here, we describe two separate incidents of an American Marten feeding on sap from
active sap wells made by Sphyrapicus varius L. (Yellow-bellied Sapsucker). To our knowledge,
these are the first recorded observations of martens feeding on sap from sap wells.
The diet of Martes americana Turton (American Marten, hereafter “marten”) is
reported to be composed primarily of small mammals, especially voles (e.g., Clethrionomys
gapperi Vigors [Southern Red-backed Vole]; Clark et al. 1987). The marten
also eats a wide variety of other foods, including fish, bird eggs, carrion, and plant
materials such as fruits, seeds, and leaves (Cumberland et al. 2001, Martin 1994, Zielinski
et al. 1983). Despite this variety, we found no reference to tree sap in its diet.
Some mammals access tree sap by chewing into the bark, such as Petaurus australis
Shaw (Yellow-bellied Glider; Goldingay 1987), whereas others visit sap wells constructed
by woodpeckers such as Sphyrapicus varius L. (Yellow-bellied Sapsucker;
Foster and Tate 1966). Sap wells are collections of small, shallow holes drilled into
the outer living tissues beneath a tree’s bark, where sap flow is greatest (Eberhardt
2000). The Yellow-bellied Sapsucker is common throughout approximately 90% of
the marten’s geographical range, where it is the only animal that routinely constructs
sap wells (Clark et al. 1987, Walters et al. 2002). In the remainder of the marten’s
range, three other sapsucker species occur (Winkler and Christie 2002). Therefore,
energy-rich sap is widely available to martens because sapsuckers construct and
maintain multiple sap wells throughout their 2–5 hectare territories (e.g., Walters et
al. 2002; H. Kitching and D.C. Tozer, pers. observ.). In this paper, we describe two
separate incidents of a marten feeding on sap at active sap wells made by Yellowbellied
Sapsuckers. To our knowledge, these are the first-ever recorded observations
of a marten feeding on sap from sap wells.
Observations. Our observations occurred in Algonquin Provincial Park, central
Ontario, Canada (45°37'N, 78°21'W) during a three-year study (2006–2008) measuring
the impact of selective harvesting on the breeding ecology of the Yellow-bellied
Sapsucker. The first incident occurred at 10:00 on 5 July 2006 in a mature hardwood
forest, with the dominant tree species being Acer saccharum Marsh. (Sugar Maple),
Fagus grandifolia Ehrh (American Beech), Tsuga canadensis L. (Eastern Hemlock),
and Betula alleghaniens.is Britton (Yellow Birch). Attracted by the alarm calls
(“waa” call, described in Walters et al. 2002) of a Yellow-bellied Sapsucker, we observed
a marten feeding at a sap well in a Sugar Maple located 35 m from a recently
fledged sapsucker nest. The marten fed for approximately five minutes, dividing
its time between licking the well itself, the bark immediately below the well, and
the leaves onto which sap had dripped. While the marten was feeding, it was divebombed
by a male sapsucker and mobbed by several songbirds that were presumably
initially attracted by the sapsuckers’ scolding calls.
Notes of the Northeastern Nat u ral ist, Issue 17/2, 2010
333
11574 Senio Avenue, Ottawa, ON K2C 1T8, Canada. 2Environmental and Life Sciences Graduate
Program, Environmental Science Centre, 1600 West Bank Drive, Trent University, Peterborough,
ON K9J 7B8, Canada. *Corresponding author - dtozer@trentu.ca.
334 Northeastern Naturalist Notes Vol. 17, No. 2
The second incident took place at 09:10 on 24 June 2008 in a mature aspen forest,
the dominant tree species being Populus tremuloides Michx. (Trembling Aspen),
Populus grandidentata Michx (Large-toothed Aspen), Betula papyrifera Marsh.
(White Birch), and Acer rubrum L. (Red Maple). Like the first incident, we were
attracted by alarm calls given by a Yellow-bellied Sapsucker, where we observed a
marten feeding at three sap wells in a Red Maple located 30 m from a sapsucker nest
that contained noisy nestlings. The marten licked sap from the wells for 10 minutes,
rarely taking a break, spending approximately 90 seconds at each well before climbing
to the next. To access all of the wells’ surface area, the marten used its hind legs,
feet, and tail to dangle from overhead branches. The feeding marten was mobbed
from within 2 m by a male Yellow-bellied Sapsucker and two Cyanocitta cristata L.
(Blue Jay). The jays dive-bombed the marten so closely that they appeared to physically
hit the marten. The sapsuckers resumed typical nestling-feeding behavior after
the marten left the tree at 09:20. At 10:03, the same or another marten returned to the
tree. It fed in the same manner as the marten previously observed in the tree, eliciting
the same aggressive mobbing response from both the sapsuckers and the jays. At
10:11, the marten made its way to a second Red Maple, located 25 m from the first,
where it also alternated between sap wells in the tree.
Discussion. Researchers investigating the marten’s diet rely primarily on the
physical remains of prey items in feces, precluding the possibility of detecting
sap consumption (Cumberland et al. 2001). Sap from active wells can have sugar
concentrations of 20–30% (g of sucrose/g of solution x 100%), potentially reaching
higher levels with evaporation (Kilham 1964, Tate 1973). These sugars could
be an important and easily accessible source of energy for martens. Tamiasciurus
hudsonicus Gmelin (Red Squirrel) has also been observed making multiple trips
to separate sap well trees on a single sapsucker territory (Kilham 1958), and Red
Squirrels systematically tap trees on their own in order to drink evaporated sap
(Heinrich 1992). Other mammals that feed directly on sap at sapsucker wells
include: Tamias striatus L. (Eastern Chipmunk), Glaucomys sabrinus Shaw
(Northern Flying Squirrel), and Erethizon dorsata L. (Porcupine) (Foster and Tate
1966). However, we witnessed sap-well feeding only twice in two different forest
habitats over a three-year period. This infrequency suggests that sap consumption
by martens may be opportunistic and uncommon, yet reflective of the wide
dietary breadth of the species.
In addition to sap, martens—like sapsuckers—may also visit sap wells to feed
on the large numbers of insects attracted to the sap. Other mammals, such as the
Red Squirrel, Northern Flying Squirrel, and bats (Myotis spp.), also feed on insects
attracted to sap wells (Foster and Tate 1966). Insect remains are frequently found
in marten scats during the warmer months of the year (2–43% of items; Bull 2000,
Francis and Stephenson 1972, Goose and Hearn 2005, Martin 1994, Newby 1951,
Weckwerth and Hawley 1962, Zielinski and Duncan 2004, Zielinski et al. 1983), and
some of these insects may be obtained from sap wells.
We are uncertain how the martens located the sap wells. Archilochus colubris
L. (Ruby-throated Hummingbird) follows sapsuckers to their wells (Foster and
Tate 1966, Lawrence 1967). Ursus americanus Pallus (American Black Bear),
the major predator of sapsucker nests in our study area, primarily uses nestling
begging calls to locate sapsucker nests, which are typically within 20–40 m of at
least one active sap-well tree (Tozer et al. 2009; H. Kitching and D.C. Tozer, pers.
observ.). It is possible that the martens we observed also used some or all of these
2010 Northeastern Naturalist Notes 335
cues to locate the sap wells. Alternatively, they might have initially been attracted
to the area with the intent to prey on adult, nestling, or fledgling sapsuckers, then
opportunistically took advantage of the sap wells. Although martens are too large
to fit through a sapsucker nest entrance (Peck and James 1983, Peterson 1966) and
they are not known to chew into sapsucker nests (Walters et al. 2002), the remains
of nestling birds and adult woodpeckers occur in their scats (Bull 2000).
Our observations show that sap from sapsucker wells occurs in the marten’s diet,
adding to the wide diversity of food items used by the marten. Similarly, the occurrence
of sap in the diets of other mammals may have been overlooked and deserves
consideration. Whether martens use sap-well resources opportunistically or whether
they visit sap wells regularly remains unknown. These observations help to further
our understanding of the complex role that sap wells play in forest ecosystems.
Acknowledgments. We thank Laurie Eberhardt, Njal Rollinson, Paul Gelok, and
two anonymous reviewers for helpful comments that improved the paper. Funding
and in-kind support was provided by Algonquin Forestry Authority, Bancroft- Minden
Forest Co., Canadian Forest Service, Canadian Wildlife Service, Enhanced
Forest Productivity Science Program, Mazinaw-Lanark Forest Inc., Natural Sciences
and Engineering and Research Council of Canada, Ontario Ministry of Natural
Resources, Ottawa Valley Forest Inc., Tembec Inc., Trent University, and Westwind
Forest Stewardship. D.C. Tozer was supported by an Ontario Graduate Scholarship
in science and technology.
Literature Cited
Bull, E. 2000. Seasonal and sexual differences in American Marten diet in Northern Oregon.
Northwest Science 74:186–191.
Clark, T.W., E. Anderson, C. Douglas, and M. Strickland. 1987. Martes americana. No.
289, In V. Hayssen (Ed.). Mammalian Species. American Society of Mammalogists,
Lawrence, KS.
Cumberland, R.E., J.A. Dempsey, and G.J. Forbes. 2001. Should diet be based on biomass? Importance
of larger prey to the American Marten. Wildlife Society Journal 29:1125–1130.
Eberhardt, L.S. 2000. Use and selection of sap trees by Yellow-bellied Sapsuckers. Auk
117:41–51.
Foster, W.I., and J. Tate, Jr. 1966. The activities and coactions of animals at sapsucker trees.
Living Bird 5:87–113.
Francis, G.R., and A.B. Stephenson. 1972. Marten ranges and food habits in Algonquin Provincial
Park, Ontario. Research Report (Wildlife) No. 91. Fish and Wildlife Research Branch,
Division of Fish and Wildlife, Toronto, ON, Canada.
Goldingay, R.L. 1987. Sap feeding by the marsupial Petaurus australis: An enigmatic behaviour?
Oecologia 73:154–158.
Goose, J.W., and B.J. Hearn. 2005. Seasonal diet of Newfoundland Martens Martes americana
atiatra. Canadian Field Naturalist 119:43–47.
Heinrich, B. 1992. Maple sugaring by Red Squirrels. Journal of Mammalogy 73:51–54.
Kilham, L. 1958. Red Squirrels feeding at sapsucker holes. Journal of Mammalogy
39:596–597.
Kilham, L. 1964. The relations of breeding Yellow-bellied Sapsuckers to wounded birches and
other trees. Auk 81:520–527.
Lawrence, L. de K. 1967. A comparative life-history study of four species of woodpeckers.
Ornithological Monographs No. 5.
Martin, S.K. 1994. Feeding ecology of American Martens and Fishers. Pp. 297–315, In S.W.
Buskirk, A.S. Harsted, M.G. Raphael, and R.A. Powell (Eds.). Martens, Sables, and Fishers:
Biology and Conservation. Cornell University Press, Ithaca, NY.
Newby, F.E. 1951. Ecology of the marten in the Twin Lakes area, Chelan county, Washington.
M.Sc. Thesis. College of Washington, Pullman, WA.
336 Northeastern Naturalist Notes Vol. 17, No. 2
Peck, G.K., and R.D. James. 1983. Breeding Birds of Ontario: Nidiology and Distribution,
Volume 1: Nonpasserines. Royal Ontario Musesum, Toronto, ON, Canada.
Peterson, R.L. 1966. The Mammals of Eastern Canada. Oxford University Press, Toronto,
ON, Canada.
Tate, J., Jr. 1973. Methods and annual sequence of foraging by the Sapsucker. Auk 90:840–856.
Tozer, D.C., E. Nol, D.M. Burke, K.A. Elliott, and K.J. Falk. 2009. Predation by bears on woodpecker
nests: Are nestling begging and habitat choice risky business? Auk 126:300–309.
Walters, E.L., E.H. Miller, and P.E. Lowther. 2002. Yellow-bellied Sapsucker (Sphyrapicus
varius). No. 662, In A. Poole and F. Gill (Eds.). The Birds of North America. The Birds of
North America Inc., Philadelphia, PA.
Weckwerth, R.P., and V.D. Hawley. 1962. Marten food habits and population fluctuations in
Montana. Journal of Wildlife Management 26:55–74.
Winkler, H., and D. Christie. 2002. Woodpeckers: A guide to the woodpeckers, piculets, and
wrynecks of the world. Pica, Sussex, UK.
Zielinski, W.J., and N.P. Duncan. 2004. Diets of sympatric populations of American Martens
(Martes americana) and Fishers (Martes pennant) in California. Journal of Wildlife Mammalogy
85:470–477.
Zielinski, W.J., W.D. Spencer, and R.H. Barrett. 1983. Relationship between food habits and
activity patterns of Pine Martens. Journal of Mammalogy 64:387–396.