Site by Bennett Web & Design Co.
2011 NORTHEASTERN NATURALIST 18(1):87–94
Bald Eagle Predation of a White-tailed Deer Fawn
Jared F. Duquette1,*, Jerrold L. Belant1, Dean E. Beyer2, Nathan J. Svoboda1,
and Craig A. Albright3
Abstract - Haliaeetus leucocephalus (Bald Eagle) is an adaptable predatory bird that
commonly captures live prey, but regularly scavenges. Large mammalian prey (e.g.,
Odocoileus virginianus [White-tailed Deer]) have been observed in Bald Eagle diets,
but were considered scavenged. To our knowledge, Bald Eagle predation of a live ungulate
has only been reported once, and occurred in Menominee County, MI. In June
2009, we captured and radiocollared a female White-tailed Deer fawn (2.7 kg) in the
south-central Upper Peninsula of Michigan. The fawn was last radiolocated alive 8 h after
release in a short-height (20–30 cm) grassland field along a river approximately 570
m from an eagle nest. Estimated time of mortality of the fawn was 10 h post release. Approximately
27 h post release, 2 legs, >50% fawn hide, and the radiocollar were present
in the nest along with 2 eagle nestlings (estimated age 9–10 wks). We believe this was a
possible predation event based on the 8-h period between fawn relocations, fawn movement,
foraging behavior of the nesting eagles, and presence of the carcass remains and
radiocollar in the nest.
Haliaeetus leucocephalus L. (Bald Eagle) has evolved life-history strategies
that include great diet plasticity. Bald Eagles commonly capture live prey, but
scavenging is regularly observed (Elliott et al. 2006, Isaacs et al. 1996, Lang
et al. 2001). Bald Eagle diet varies with season and geographic region (e.g.,
Isaacs et al. 1996, Jackman et al. 1999) and primarily includes fish (e.g., Kozie
and Anderson 1991, Lang et al. 2001), but also birds (Morris 2002, Ricca et al.
2004), reptiles (Means and Harvey 1999), invertebrates (Jackman et al. 1999,
Murie 1940), and mammals (Isaacs et al. 1996, Kozie and Anderson 1991).
Medium-sized mammals reported in their diet include hare and rabbit (Family
Leporidae; Dominguez et al. 2003, Hunt et al. 2002, Kozie and Anderson 1991),
Enhydra lutris L. (Sea Otter; Anthony et al. 1999, Ricca et al. 2004), Alopex
lagopus L. (Arctic Fox; Anthony et al. 2008, Murie 1940), and Procyon lotor L.
(Raccoon; Lang et al. 2001). Additionally Odocoileus virginianus Zimmermann
(White-tailed Deer) (Kozie and Anderson 1991, Lang et al. 2001), O. hemionus
Rafinesque (Mule Deer; Isaacs et al. 1996), Cervus elaphus L. (Elk; Isaacs et al.
1996), Rangifer tarandus L. (Caribou; Anthony et al. 2008), Canis latrans Say
1Carnivore Ecology Laboratory, Forest and Wildlife Research Center, Mississippi State
University, Box 9690, Mississippi State, MS 39762. 2Michigan Department of Natural
Resources and Environment, Wildlife Division, 1990 US Highway 41 S, Marquette, MI
49855. 3Michigan Department of Natural Resources and Environment, Wildlife Division,
6833 US Highway 2 41 M35, Gladstone, MI 49837. *Corresponding author - jduquette@
88 Northeastern Naturalist Vol. 18, No. 1
(Coyote; Isaacs et al. 1996), Bos spp.(domestic cattle; Isaacs et al. 1996), and
Ovis spp. (domestic sheep; Murie 1940) have been observed in diets but were
Although mammalian prey is commonly found in Bald Eagle diets, it is unclear
to what extent these species, particularly larger species, are predated. To
our knowledge, the only documented case of Bald Eagle ungulate predation occurred
19 June 1960 in Menominee County, MI (Line 1961). Observers stated the
fawn appeared “tiny” and was thought to be several days old, weighing between
2.5–3.4 kg. In this case, the eagle appeared to capture the fawn alive and had no
difficulty carrying the fawn in flight. Also, a complete fawn carcass was found
on 10 June 2010 in a Bald Eagle nest along the Days River near Rapid River,
MI, (G. Zuehlke, Michigan Department of Natural Resources and Environment,
Escanaba, MI, pers. comm.). The fawn was estimated at 1 d of age, based on
new hoof growth of the right rear leg (Sams et al. 1996) and a weight of 3.6 kg
(Carstensen et al. 2009), and was found 22.3 km northeast of the fawn mortality
We describe Bald Eagle brood provisioning of a White-tailed Deer fawn and
the circumstances surrounding a potential fawn predation.
A White-tailed Deer fawn was captured at 10:48 on 5 June 2009 in a grassland
field adjacent to a primary roadway and 40-m-wide river (Fig. 1), as part
of a predator-prey study in the south-central Upper Peninsula of Michigan
(45°43'47"N, 87°4'48"W). This fawn was 1 of 48 captured and radiocollared
during spring 2009. Immediately upon capture, we determined sex, recorded
rectal temperature, estimated weight to the nearest 0.1 kg with a spring scale,
and measured to the nearest mm new front right hoof growth to estimate age
(Sams et al. 1996; J. Duquette et al., Mississippi State University, Mississippi
State, MS, unpubl. data), body length, and right front shoulder height.
The fawn was fitted with an expandable VHF radiocollar (Diefenbach et
al. 2003; Advanced Telemetry Systems, Isanti, MN) with an 8-h mortality
switch and precise event transmitter (PET) to estimate time of mortality to the
nearest half-hour. The mortality switch is activated after the radiocollar has
not moved for a period of 8 h. The PET is a sequence of coded radio pulses
emitted from the collar after the mortality switch is activated, which is then
decoded to approximate time of collar inactivity (e.g., mortality). We did not
use immobilization drugs, and the fawn was released at the capture site immediately
following handling. We attempted to locate the fawn every 8 h using a
truck-mounted radiotelemetry system.
At capture, the female fawn weighed 2.7 kg and had a body length of 61.1
cm and shoulder height of 46.9 cm. We estimated the fawn was 3 d old. Total
2011 J.F. Duquette, J.L. Belant, D.E. Beyer, N.J. Svoboda, and C.A. Albright 89
handling time was 17 min, and we did not observe or hear eagles while handling
the fawn. The fawn was released at the capture site about 20 m from the road and
was fully ambulatory and displayed normal behavior (i.e., bedded) upon release.
The dam remained ≤150 m from the fawn during handling, appeared in good
physical condition, and was vocal toward handlers.
Figure 1. South-central Upper Peninsula of Michigan (top, black dot) and location (bottom)
where a White-tailed Deer fawn was predated 5 June 2009 by a Bald Eagle. Fawn
capture site is location where fawn was radiocollared, fawn relocation site is radiolocation
of fawn 8 h after release, and eagle nest site is final location of the collar.
90 Northeastern Naturalist Vol. 18, No. 1
We radiolocated the fawn 8 h after capture (≈18:48) on the edge of a shortheight
(20–30 cm) grassland field (≤0.6 ha) about 30 m from the river, 190
m from the capture site (roadside), and 570 m from the eagle nest. We did
not observe the fawn or detect fawn movement during this radiolocation.
While obtaining a radiolocation 12 h after capture (≈22:48), we detected a 2-h
mortality (PET) signal, indicating the collar was stationary since 10 h post
capture and estimating mortality time around 20:48. However, upon detection
of the mortality pulse, the exact location of the collar was not recorded.
Approximately 27 h after capture, on 6 June 2009 at 14:23, we located the
fawn radiocollar on mortality pulse in a Bald Eagle nest about 25 m above
ground and 1.1 km from the fawn capture location. We climbed to the nest
and observed 2 live eagle nestlings (estimated age 9–10 wks) and 2 fawn legs
(1 front and 1 hind), >50% of the fawn’s hide, and the radiocollar (Fig. 2).
Leg bones were void of flesh and connected at the joints and the remaining
hide was ripped sharply into 2 pieces; tufts of fawn hair were scattered across
the nest. We retrieved the radiocollar, but did not attempt to retrieve or search
for additional carcass remains to reduce disturbance to eagle nestlings. Both
adult eagles were observed during the nest visit.
White-tailed Deer dams frequently leave fawns in habitat offering concealment
as an anti-predatory strategy, allowing dams to forage away from the fawns
before returning to nurse every few hours (Ozoga and Verme 1986, Ozoga et al.
1982). However, dams view this concealment from ground level and may not
consider vertical cover. The radiocollared fawn was located 8 h after its release
in a grassland patch that provided minimal concealment from above. An eagle
could have detected and attacked the fawn from the air, particularly if the dam
was foraging away from the fawn.
We cannot exclude the possibility that eagles observed or were attracted to
research personnel during the fawn’s capture, or that our handling influenced
fawn behavior potentially increasing predation risk. However, we believe it is
probable the fawn presented an opportunistic prey item secured while eagles
hunted the riparian area near their nest. The adjacent river was likely a common
foraging area for the eagles, supported by the numerous fish remains
observed in and around the nest. Very low water in the river during June
may have limited fish availability, requiring eagles to hunt adjacent fields
for mammalian prey. Hunt et al. (2002) suggested Bald Eagles may switch
to mammalian prey when fish are less available. Upon nest investigation, we
observed one of the adult eagles carrying a sciurid, which may suggest the
Figure 2 (opposite page). Bald Eagle nest (nestlings pictured) where White-tailed Deer
fawn carcass and radiocollar were retrieved 6 June 2009 following predation in southcentral
Upper Peninsula of Michigan. Arrows in top panel indicate fawn radiocollar (top
arrow) and leg (bottom arrow).
2011 J.F. Duquette, J.L. Belant, D.E. Beyer, N.J. Svoboda, and C.A. Albright 91
92 Northeastern Naturalist Vol. 18, No. 1
eagles possibly were focusing their foraging around fields or wooded areas
rather than water. This foraging strategy may have increased the likelihood of
observing the fawn opportunistically.
The fawn may have been scavenged following a vehicle collision. However,
this is unlikely due to the minimal time between capture and mortality
(10 h) and the distance (about 190 m) between the 8-h radio location of the
fawn and the road. Fawn mortality was estimated around 20:48, which would
have provided approximately an hour to an hour and a half before sunset, thus
providing a period of light for foraging and transporting the fawn to the nest.
Also, although the location of the radiocollar was not obtained upon mortality
pulse detection, we highly suspect it was in the nest at this time because it
was on mortality pulse upon nest investigation and motion (e.g., eagle flying)
would have likely put the collar on normal pulse. Nevertheless, the radiocollar
could have gone into mortality mode again if the eagles did not disturb
it 8 h after transporting it to the nest and nest investigation. Furthermore,
it is improbable the eagles commandeered the carcass from a mammalian
predator (e.g., coyotes) because Bald Eagles are subordinate to these species
(McCollough et al. 1994). Also, the fawn’s rectal temperature was normal (39
°C) during handling, indicating low risk of acute capture myopathy (Beringer
et al. 1996, DelGiudice et al. 2001); thus, we believe it is unlikely that the
fawn died before being detected by an eagle and was simply scavenged.
Whether the eagle transported the fawn to the nest in 1 or multiple trips is
unknown; however, the eagle(s) would have had 25–26 h to feed on and transport
the fawn to the nest. Although we only observed 2 fawn legs in the nest, we
believe the fawn was taken in 1 trip because >50% of the hide and radiocollar
were in the nest. Further, 1 live (Line 1961) and 1 dead (J. Duquette, unpubl.
data) fawn of similar weight (2.1–6.0 kg) were observed to be taken by a Bald
Eagle within 25 km of the suspected fawn predation described. Considering the
aforementioned evidence, we conclude the radiocollared fawn in our study may
have been predated by a Bald Eagle.
This project was supported by the Federal Aid in Wildlife Restoration Act under
Pittman-Robertson project W-147-R. We thank the Michigan Department of Natural
Resources and Environment, Safari Club International Foundation, and Safari Club International
Michigan Involvement Committee for project support. We thank L. Fuentes,
W. Neser, and N. Harri for their assistance in retrieving the radiocollar and taking nest
photos. Much gratitude to G. Zuehlke for additional fawn observation information and T.
Petroelje, C. Ayers, R. Karsch, H. Stricker, C. Wilton, O. Duvuvuei, E. High, M. Jones,
E. Bouckaert, and L. Fouladbash who captured and radiolocated deer fawns.
Anthony, R.G., A.K. Miles, J.A. Estes, and F.B. Isaacs. 1999. Productivity, diets, and
environmental contaminants in nesting Bald Eagles from the Aleutian archipelago.
Environmental Toxicology and Chemistry 18:2054–2062.
2011 J.F. Duquette, J.L. Belant, D.E. Beyer, N.J. Svoboda, and C.A. Albright 93
Anthony, R.G., J.A. Estes, M.A. Ricca, A.K. Miles, and E.D. Forsman. 2008. Bald Eagle
and Sea Otters in the Aleutian archipelago: Indirect effects of trophic cascades. Ecology
Beringer, J., L.P. Hansen, W. Wilding, J. Fischer, and S.L. Sheriff. 1996. Factors affecting
capture myopathy in White-tailed Deer. Journal of Wildlife Management
Carstensen, M., G.D. DelGiudice, B.A. Sampson, and D.W. Kuehn. 2009. Survival, birth
characteristics, and cause-specific mortality of White-tailed Deer neonates. Journal of
Wildlife Management 73:175–183.
Delgiudice, G.D., B.A. Mangipane, B.A. Sampson, and C.O. Kochanny. 2001. Chemical
immobilization, body temperature, and post-release mortality of White-tailed Deer
captured by clover trap and net-gun. Wildlife Society Bulletin 29:1147–1157.
Diefenbach, D.R., C.O. Kochanny, J.K. Vreeland, and B.D. Wallingford. 2003. Evaluation
of an expandable breakaway radiocollar for White-tailed Deer fawns. Wildlife
Society Bulletin 31:756–761.
Dominquez, L., W.A. Montevecchi, N.M. Burgess, J. Brazil, and K.A. Hobson. 2003.
Reproductive success, environmental contaminants, and trophic status of nesting Bald
Eagles in eastern Newfoundland, Canada. Journal of Raptor Research 37:209–218.
Elliott, K.H., J. Duffe, S.L. Lee, P. Mineau, and J.E. Elliott. 2006. Foraging ecology of
Bald Eagles at an urban landfill. The Wilson Bulletin of Ornithology 118:380–390.
Hunt, W.G., R.E. Jackman, D.E. Driscoll, and E.W. Bianchi. 2002. Foraging ecology of
nesting Bald Eagles in Arizona. The Journal of Raptor Research 36:245–255.
Isaacs, F.B., R.G. Anthony, M. Vander Heyden, C.D. Miller, and W. Weatherford. 1996.
Habits of Bald Eagles wintering along the Upper John Day River, Oregon. Northwest
Jackman, R.E., W.G. Hunt, J.M. Jenkins, and P.J. Detrich. 1999. Prey of nesting Bald
Eagles in northern California. Journal of Raptor Research 33:87–96.
Kozie, K.D., and R.K. Anderson. 1991. Productivity, diet, and environmental contaminants
in Bald Eagles nesting near the Wisconsin shoreline of Lake Superior. Archives
of Environmental Contamination and Toxicology 20:41–48.
Lang, A.L., R.A. Andress, and P.A. Martin. 2001. Prey remains in Bald Eagle (Haliaeetus
leucocephalus) pellets from a winter roost in the Upper St. Lawrence River, 1996 and
1997. Journal of Wildlife Rehabilitation 24:21–26.
Line, L. 1961. Bald Eagle preys on White-tailed Deer fawn. Jack-Pine Warbler
McCollough, M.A., C.S. Todd, and R.B. Owen, Jr. 1994. Supplemental feeding program
for winter Bald Eagles in Maine. Wildlife Society Bulletin 22:147–154.
Means, D.B., and A. Harvey. 1999. Barbours’s Map Turtle in the diet of nesting Bald
Eagles. Florida Field Naturalist 27:14–16.
Morris, D. 2002. Bald Eagle kills Common Loon. Loon 74:57.
Murie, O.J. 1940. Food habits of the northern Bald Eagle in the Aleutian Islands, Alaska.
Ozoga, J.J., and L.J. Verme. 1986. Relation of maternal age to fawn-rearing success in
White-tailed Deer. Journal of Wildlife Management 50:480–486.
Ozoga, J.J., L.J. Verme, and C.S. Bienz. 1982. Parturition behavior and territoriality in
White-tailed Deer: Impact on neonatal mortality. Journal of Wildlife Management
94 Northeastern Naturalist Vol. 18, No. 1
Ricca, M.A., R.G. Anthony, and J.C. Williams. 2004. Bald Eagles consume Emperor
Geese during late-winter in the Aleutian archipelago. Journal of Raptor Research
Sams, M.G., R.L. Lochmiller, E.C. Hellgren, W.D. Warde, and L.W. Varner. 1996. Morphometric
predictors of neonatal age for White-tailed Deer. Wildlife Society Bulletin