Whooping cranes (Grus americana) currently consist of a single, wild population that migrates annually from breeding grounds at Wood Buffalo National Park, Canada, to wintering grounds on and around the Aransas National Wildlife Refuge along the Texas coast, USA (NRC 2005). This population reached a low of less than 20 individuals in 1941 (Allen 1952) but has rebounded to over 250 individuals (Chavez-Ramirez and Wehtje 2012, Gil-Weir et al. 2012). Whooping cranes migrate approximately 4,000 km each spring and autumn, traversing much of the North American Great Plains (Lewis 1995) and periodically landing along rivers, wetlands, and other shallow bodies of water for short-duration stopovers (Austin and Richert 2001).
Our observations represent some of the few published accounts of a frog species being consumed by whooping cranes along the Central Flyway

Assenmacher, Michael J.

Geluso, Keith

Harner, Mary J.

Krohn, Brad T.

English

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University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
The Prairie Naturalist Great Plains Natural Science Society 
12-2013 
Whooping Cranes Consume Plains Leopard Frogs at Migratory 
Stopover Sites in Nebraska 
Keith Geluso 
University of Nebraska at Kearney, gelusok1@unk.edu 
Brad T. Krohn 
United States Fish and Wildlife Service, Funk, Nebraska 
Mary J. Harner 
The Crane Trust, harner.mary@gmail.com 
Michael J. Assenmacher 
United States Fish and Wildlife Service, Funk, Nebraska 
Follow this and additional works at: https://digitalcommons.unl.edu/tpn 
 Part of the Biodiversity Commons, Botany Commons, Ecology and Evolutionary Biology Commons, 
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Geluso, Keith; Krohn, Brad T.; Harner, Mary J.; and Assenmacher, Michael J., "Whooping Cranes Consume 
Plains Leopard Frogs at Migratory Stopover Sites in Nebraska" (2013). The Prairie Naturalist. 59. 
https://digitalcommons.unl.edu/tpn/59 
This Article is brought to you for free and open access by the Great Plains Natural Science Society at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Prairie Naturalist by 
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The	Prairie	Naturalist	45:91–93;	2013
NOTES
WHOOPING CRANES CONSUME PLAINS LEOP-
ARD FROGS AT MIGRATORY STOPOVER SITES 
IN NEBRASKA—Whooping	 cranes	 (Grus americana) 
currently consist of a single, wild population that migrates 
annually from breeding grounds at Wood Buffalo National 
Park, Canada, to wintering grounds on and around the Aran-
sas National Wildlife Refuge along the Texas coast, USA 
(NRC	2005).	This	population	reached	a	low	of	less	than	20	
individuals	in	1941	(Allen	1952)	but	has	rebounded	to	over	
250	individuals	(Chavez-Ramirez	and	Wehtje	2012,	Gil-Weir	
et al. 2012). Whooping cranes migrate approximately 4,000 
km each spring and autumn, traversing much of the North 
American	Great	Plains	(Lewis	1995)	and	periodically	land-
ing along rivers, wetlands, and other shallow bodies of water 
for	short-duration	stopovers	(Austin	and	Richert	2001).	
Winter diets of whooping cranes have received moder-
ate	attention,	with	cranes	mainly	feeding	on	blue	crabs	(Cal-
linectes sapidus)	and	clams	(e.g.,	Tagellus plebius), as well 
as	 fish,	 snails,	 acorns,	 fruit	 of	 Carolina	wolfberry	 (Lycium 
caroliniana),	crayfish,	insects,	and	other	items	(Allen	1952,	
Hunt and Slack 1989, Chavez-Ramirez 1996). On 4 Febru-
ary 2012, a whooping crane was observed consuming a gulf 
saltmarsh	watersnake	(Nerodia clarkii clarkii) on wintering 
grounds at the Aransas National Wildlife Refuge, but such 
uncommon items likely contribute more to diets during years 
with	limited	blue	crabs,	such	as	the	winter	2011–2012	(Gelu-
so and Harner 2013a). Little is known about diets of whoop-
ing cranes on summer breeding grounds, but adult cranes 
have been observed feeding colts prey dominated by nymph 
dragonflies	 (Libellula sp. and Aeshna	 sp.;	 Bergeson	 et	 al.	
2001). During migration, relatively little is known about diets 
of	cranes	(Lewis	1995),	and	most	information	about	prey	is	
surmised	(e.g.,	documentation	of	potential	prey	at	sites	pre-
viously	visited	by	whooping	cranes;	Allen	1952,	Austin	and	
Richert	2001),	but	animal	matter	likely	is	important	(USFWS	
1981). In this report we describe observations of whooping 
cranes	feeding	upon	Plains	leopard	frogs	(Lithobates blairi) 
in south-central Nebraska, adding to the scant information of 
prey consumed during migration.
On 29 March 2012, a whooping crane consumed a Plains 
leopard frog in a shallow, upland pond in northern Harlan 
County,	Nebraska,	USA	 (40.3100°N,	 99.4431°W;	 19.9	 km	
N, 0.9 km E Orleans). The pond was situated in the bottom 
of a valley in an area with rolling grasslands. The area was 
grazed the previous year, and there was no vegetation in or 
along the water’s edge. Eleven adult-plumaged whooping 
cranes were observed at the pond at 1500 hr for 30 min. Eight 
cranes appeared to rest while standing in about 20 cm of wa-
ter. Three other individuals actively foraged in the pond. One 
crane detected and stabbed a frog with its beak in a manner 
similar to immobilizing crabs and other larger prey on win-
tering	grounds	(Lewis	1995).	The	crane	proceeded	to	lift	the	
frog from the water, and other cranes noticed the foraging 
behavior. Two other foraging cranes then pursued the indi-
vidual carrying the frog. When the crane that captured the 
frog dropped it, another crane quickly grabbed the frog with 
its	beak,	flipped	 it	 into	 the	air,	and	consumed	it	 in	a	single	
swallow without further manipulation.
On 17 April 2012, another adult-plumaged whooping 
crane consumed a Plains leopard frog at the Cottonwood Fed-
eral Waterfowl Production Area in western Phelps County, 
Nebraska,	USA	(40.5455°N,	99.5892°W;	2.2	km	N,	3.8	km	
E Bertrand). The shallow wetland habitat was partially sur-
rounded by grazed upland grasslands at the Federal Water-
fowl Production Area, and croplands dominated by center-
pivot irrigation surrounded the site. Two whooping cranes 
were observed probing and feeding in emergent vegetation 
on the southwest side of the open water at 1430 hr for 15 min. 
One	whooping	crane	captured	a	leopard	frog,	flipped	it	into	
the air, and consumed it quickly. At this site and the one listed 
above, we surveyed aquatic habitats and their surrounding 
edges	 for	bullfrogs	 (L. catesbeianus). We did not detect or 
find	evidence	of	adults	or	tadpoles	in	these	shallow	waters,	
confirming	our	 identification	of	 frogs	 from	a	distance.	The	
plains leopard frog is the only species of spotted Lithobates 
species	in	the	area	(Ballinger	et	al.	2010,	Fogell	2010).
Though uncertain, leopard frogs might be an important 
prey item for whooping cranes on stopover sites due to their 
distribution throughout the Great Plains. Plains leopard frogs 
occur in freshwater habitats from southern South Dakota to 
central	Texas	(Brown	1992),	and	northern	leopard	frogs	(L. 
pipiens)	inhabit	more	northerly	reaches	of	the	migratory	fly-
way	(Stebbins	2003).	Leopard	frogs	are	important	prey	items	
for various vertebrate species because they are seasonally 
abundant, especially after metamorphosed froglets emigrate 
from	 aquatic	 habitats	 (Geluso	 and	 Harner	 2013b). Known 
predators of adult and metamorphosed leopard frogs include 
fish	(Lundgren	et	al.	2012),	snakes	(Hammerson	1982,	Ernst	
and Ernst 2003, Geluso and Harner 2013b), amphibians 
(Smith	1977),	mammals	(Shirer	and	Fitch	1970),	and	other	
birds	(Robinson	1957).
Whooping cranes migrate through Nebraska later in 
spring	than	most	waterfowl	and	sandhill	cranes	(G. canaden-
sis;	Sharpe	et	al.	2001),	possibly	reflecting	increased	avail-
ability of vertebrate prey later in the season. Frogs and other 
herpetofauna are more active during late March and through-
out	April	 (Geluso	 and	 Harner	 2013b) than when sandhill 
cranes migrate and stage along the Platte River in February 
and March. Herpetofauna also are active in autumn in central 
Nebraska	(Goldowitz	and	Whiles	1999,	Geluso	and	Harner 
2013b) when whooping cranes migrate through the region 
(Sharpe	et	al.	2001).	Frogs	and	other	animal	prey	items	might	
92 The Prairie Naturalist		•		45(2):	December	2013
be especially important during whooping crane migration 
when	major	food	resources	(e.g.,	crabs	and	clams)	are	scarce	
on wintering grounds, as they were in winter 2011–2012. For 
migratory birds, lipid and energy reserves obtained on win-
tering grounds and during migratory stopovers are important 
because their body condition affects reproductive success, 
egg size, and other adaptive characteristics and behaviors on 
breeding	grounds	(Drent	et	al.	2006).	
Our observations represent some of the few published ac-
counts of a frog species being consumed by whooping cranes 
along the Central Flyway. On breeding grounds in Canada a 
chorus	frog	(Pseudacris maculata) was purportedly fed to a 
young	colt,	but	details	are	 lacking	on	 that	observation	 (see	
Bergeson et al. 2001). On wintering grounds in Texas the Rio 
Grande	leopard	frog	(L. berlandieri) was listed as a species 
with	reasonable	certainty	of	being	a	prey	item	(Allen	1952).	
However,	amphibians	do	not	appear	to	represent	a	significant	
part of whooping crane diets during winter when cranes feed 
mainly	 in	 tidal	 flats	 and	 coastal	 brackish	 waters	 (Chavez-
Ramirez 1996). In contrast, frogs likely are an underestimat-
ed important food resource for these primarily animalivorous 
birds that frequent freshwater habitats during migration and 
on breeding grounds. Only a single observation of an un-
known species of frog has been reported as prey for whoop-
ing	cranes	during	migration	(Austin	and	Richert	2001).	How-
ever,	Austin	and	Richert	(2001)	observed	that	frogs	were	the	
second most frequent potential animal prey available on both 
feeding and roost sites, besides invertebrates, during migra-
tion. Understanding whooping crane diets at stopovers sites 
will help resource managers promote and maintain habitats 
as well as dietary resources for whooping cranes migrating 
along the Central Flyway.
We thank M. Tacha and J. Jenniges for providing informa-
tion about whooping crane foraging.—Keith Geluso1,4, Brad 
T. Krohn2, Mary J. Harner3, and Michael J. Assenmacher2. 
1Department of Biology, University of Nebraska at Kearney, 
Kearney, NE 68849, USA; 2Rainwater Basin Wetland Man-
agement District, U.S. Fish and Wildlife Service, Funk, NE 
68940, USA; 3The Crane Trust, 6611 Whooping Crane Drive, 
Wood River, NE 68883, USA; 4Corresponding author e-mail 
address: gelusok1@unk.edu.
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Submitted 26 September 2012. Accepted 4 June 2013. Associ-
ate Editor was Daniel Fogell.


Whooping Cranes Consume Plains Leopard Frogs at Migratory Stopover Sites in Nebraska

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Whooping Cranes Consume Plains Leopard Frogs at Migratory Stopover Sites in Nebraska

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