LOCOMOTION OF WOOD DUCKS

LOCOMOTION
OF WOOD DUCKS
BY PAUL A. STEWART
A
STUDY of several aspects of the life history of the Wood Duck
sponsa) was recently conducted in central Ohio.
(Aix
Survival was of pri-
mary concern, and some attention was given to the means utilized by this
species for escape from capture. Although speed alone seldom assures escape
from pursuing predators, it is a pertinent factor in maximum
escape effi-
ciency. The readiness with which Wood Ducks move into different environments may be a more important
is sometimes more meaningful
life-saver than speed itself, but versatility
to the extent that it is supplemented with
quick changes. How quickly can a pursued Wood Duck move from land to
water or from water to land?
ACKNOWLEDGMENT
This paper is a contribution from the Ohio CooperativeWildlife Research Unit: U.S.
Fish and Wildlife Service, Ohio Division of Wildlife, Wildlife Management Institute, and
the Ohio State University cooperating. I am indebted to Eugene H. Dustman and Milton
B. Trautman for critical readings of the manuscript, and to the former for guidance and
financial support throughout the course of the study. I am also indebted to Maurice
Giltz and Ernest E. Good for aid in making the counts of wing beats.
SWIMMING SPEED
It is difficult to obtain data on maximum swimming speeds of Wood Ducks
because, when pressed, the flightless young either dive beneath or skitter over
the surface of the water, and the fully feathered ducks take flight. As would be
expected from its slowness, swimming alone is used for only leisurely escapes.
Three measurements of swimming speeds were obtained for day-old ducklings. For these measurements a lane was constructed of two pieces of chicken
wire placed parallel in a vertical position about 6 inches apart and extending
from the shore toward the center of a pond. This lane was 20 feet long and
the wire extended 4 inches above the surface of the water.
The ducklings
were released near the shore into the lane, and the time they spent in swimming at an approximately
uniform
speed was measured with a stop watch.
When the birds ceased swimming and dived or skittered over the water, the
watch was stopped and the swimming distance was measured.
urements were taken immediately
speedy method of escape, it is believed that approximately
ming speeds were recorded.
As the meas-
before the ducklings resorted to a more
maximum
swim-
The speeds of 3 ducklings ranged from 0.8 to
1.2 feet per second with an average of 0.9 foot per second or 0.6 of a mile
per hour.
Hochbaum
(Aythya disineria)
(1944:120)
reported that flightless adult Canvasbacks
swim at a rate of 2 to 3 miles per hour.
184
Paul A.
WOOD
stewart
DUCK
LOCOMOTION
DIVING
When pressed immediately on leaving the nest, the ducklings dived and
swam under water for short distances. The length of time four ducklings
just out of the nest remained under water was measured with a stop watch;
the periods of submergence varied from 7 to 13 seconds. One day-old duckling came to the surface 7.5 seconds after diving 16 feet from the spot where
it had submerged.
When under water, this bird swam an average of more
than 2 feet per second.
By the time the ducklings were 3 to 4 weeks of age, they swam submerged
through much greater distances. Unsuccessful attempts were made to determine the time spent and the distance moved under water by ducklings at
more advanced ages. Ducklings more than 2 to 3 weeks of age seldom reappeared on the surface of the water before reaching protective plant cover.
Sites 75 feet from the nearest shore were chosen for the release of several
ducklings 3 to 4 weeks of age in an effort to measure their time and distance
under water, but in each case the ducklings were not seen again.
When
ducklings were released near the shore, they commonly dived, swam a short
distance, came out on the shore, and ran into plant cover. Presumably these
birds which were not seen after being released 75 feet from shore swam all
of the distance to plant cover before they emerged from the water.
SKITTERING SPEED
Skittering is accomplished by the duck’s elevating the anterior part of its
body higher than in swimmin g and by running, with much splashing, over
the surface of the water.
One measurement of the skittering speed of a day-
old duckling was made in a similar method to those of the swimming speeds.
This duckling skittered at the rate of 8.5 feet per second or 5.8 miles per
hour for a distance of 17 feet. The skittering speed of an adult male in the
flightless stage of the postnuptial molt was 75 feet in 5.4 seconds, a rate of
14.0 feet per second or 9.5 miles per hour. This is faster than the maximum
terrestrial speed of 13.3 feet per second or 9.1 miles per hour for the Red
Squirrel
103).
(Tamiasciurus
Hochbaum
hudsonicus) reported by Layne and Benton (1954:
(1944:120)
reported a skittering speed for flightless male
Canvasbacks of 8 to 10 miles per hour.
RUNNING SPEED
Tests of running speed were made on a plot of almost-level, closely-grazed
pasture.
A liberal application of paint was smeared on the bottoms of the
ducklings’ feet before release. Measurements of strides included the distance
from the anterior end of one track to the anterior end of the next track. The
time travelled in an approximately
straight line was measured with a stop
watch. In spite of the fact that ducks in general do not appear well adapted
186
THE
WILSON
June 1958
Vol. 70, No. 2
BULLETIN
for running, young Wood Ducks can run rather rapidly,
and one bird 3 to
4 weeks of age ran 10.4 feet per second for 24 feet. During the first several
yards, which are not included in this calculation, its strides were only about
5 inches long, but after running
several yards its strides lengthened to 8
inches. Each of three other ducklings 3 to 4 weeks of age ran 8 to 9 feet
per second. The strides of two of these ducklings were 7 to 8 inches long,
but one duckling made strides 12.5 inches long. This duckling did not move
correspondingly faster and covered only 8 feet per second. These ducklings
made 7.7 to 15.4 strides per second, or each stride required one-eighth to
one-fifteenth
second of time.
They ran at the rate of 5.5 to 7.1 miles per
hour. The maximum observed terrestrial speed of a Wood Duck was 12 feet
per second or 8.2 miles per hour. This was the performance of a bird 6 to
7 weeks of age.
The maximum running speed of 8.2 miles per hour is not markedly lower
than running speeds recorded for some terrestrial species of birds. Cottam,
Williams, and Sooter (1942 :131) recorded maximum running speeds of 10
miles per hour for three Ring-necked Pheasants (Phasianus colchicus), and
12 and 15 miles per hour for two Road-runners
(Geococcyx californianus).
Even among mammals maximum running speeds of only 10.6 miles per hour
for the Chipmunk
(Tam&
striutus),
miles per hour for the Gray Squirrel
9.1 for the Red Squirrel,
(Sciurus curolinemis)
and 17.0
have been re-
ported by Layne and Benton (1954:103).
FLIGHT
The flight speeds of eight Wood Ducks over a distance of 204 feet were
measured through the use of a stop watch. The watch was started when the
birds had flown approximately five feet after being released. There was little
or no wind when the measurements were made, and the birds flew almost
horizontally.
The flight speed of these eight birds averaged 4.5.8 feet per
second or 31.2 miles per hour with a range of 27.8 to 34.8 miles per hour.
Because of variations under which the birds were flying, as well as variations in making measurements, it is difficult to find published data on flight
speeds for comparison.
Speeds from 26 to 72 miles per hour have been
recorded (Cooke, 1937)
for various species of ducks. McLean
noted that the speed of a Cinnamon Teal (Anus cyanopera)
(1930:1-2)
increased from
32 to 59 miles per hour when the bird was chased. Doubtless a higher speed
could be attained after flight had been in progress for a longer period of
time than was the case in this experiment with Wood Ducks.
Motion pictures were taken of four Wood Ducks when flying in order to
determine the number of wing beats per unit of time.
These birds were fol-
lowed with the camera for several hundred feet after they were released. The
PaulA.
stewart
WOOD
DUCK
187
LOCOMOTION
pictures were projected at a slower speed and the wing beats of the birds on
the screen were counted. These four birds made 7 to 7.5 wing beats per
,second. Aymar (1935:144) reported that the Goldeneye (Bucephala clan&r
.americana)
makes 9 wing beats per second. At 31.2 miles per hour, the
Wood Duck moves approximately
6.5 feet at each wing beat.
SUMMARY
1. Day-old ducklings when pressed swam an average of 0.9 foot per second or 0.6 of
a mile per hour.
2. Day-old ducklings remained submerged a maximum of 13 seconds. One swam 16
feet under water.
3. One day-old duckling skittered over the water at the rate of 8.5 feet per second or
5.8 miles per honr. An adult male in the flightless stage of the postnuptial molt skittered at the rate of 14.0 feet per second or 9.5 miles per hour.
4. Three Wood Ducks at 3-4 weeks of age ran a maximum of 10.4 feet per second.
The longest strides were 12.5 inches. The maximum running speed was 12 feet per
second or 8.2 miles per hour by a bird 667 weeks of age.
5. The average flight speed of eight Wood Ducks soon after being released was 31.2
miles per hour.
6. Four Wood Ducks in flight made 7 to 7.5 win g beats per second, moving forward
approximately
6.5 feet with each wing heat.
LITERATURE CITED
AYMAR, G. C.
1935 Bird flight. Garden City Publishing Co. 234 pp.l
COOKE, M. T.
1937 Flight speed of birds. U.S. Dept. of Agric. Circ. No. 428.
,COTTAM, C., C. S. WILLIAMS AND C. A. SOOTER
1942 Flight and running speeds of birds. Wilson Bull., 54:121-131.
HOCHBAUM, H. A.
1944 The canvashack on a prairie marsh. Washington, D.C., Amer. Wildl.
201 pp.
LAYNE, J. N. AND A. H. BENTON
1954 Some speeds of small mammals. Jour. Mammalogy, 35:103-104.
MCLEAN, D. D.
1930 The speed of flight in certain birds. Gull, 12:1-2.
C
‘ ited
with
INDIANA
the
permission
DEPARTMENT
INDIANAPOLIS,
of
Dodd,
Mead
& Company.
OF CONSERVATION,
INDIANA,
Inst.,
AUGUST 15, 1957
311 WEST
WASHINGTON
STREET,