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C.D. Mason, R.M. Whiting, Jr., and W.C. Conway
22001133 SOUTSoHuEthAeSaTsEteRrnN NNaAtTurUaRliAstLIST 1V2o(4l.) :1725,7 N–7o6. 84
Time-activity Budgets of Waterfowl Wintering on Livestock
Ponds in Northeast Texas
Corey D. Mason1, R. Montague Whiting, Jr.2, and Warren C. Conway3,*
Abstract - We developed individual time-activity budgets for Anas platyrhynchos (Mallard;
n = 281), A. strepera (Gadwall; n = 251), and Aythya collaris (Ring-necked Duck; n = 144)
wintering on livestock ponds in the Blackland Prairies Ecological Region of Texas in January
and February, 2000 and 2001. Feeding (32–38%), locomoting (24–49%), and resting
(10–36%) dominated the activity budgets for each species. Behaviors varied between years,
probably due to the 3-fold increase in precipitation that raised water levels in livestock
ponds. In 2000 and 2001, Mallards fed nearly 50% and 20% of their time, respectively, with
comfort and resting occupying 60% in 2001. Gadwalls locomoted nearly 50% of their time
each year, but increased surface feeding 2-fold in 2001. Finally, Ring-necked Ducks spent
about a third of their time locomoting, another third resting, and the remainder subsurface
feeding in 2001. Focal species activity budgets were generally similar to those developed
throughout their ranges. Livestock ponds in northeast Texas provide small but regionally
widespread habitats for wintering waterfowl. Future work should focus upon diet and landscape
occupancy rates of waterfowl using these habitats during winter.
Introduction
Annual mid-winter aerial surveys performed by the Texas Parks and Wildlife
Department (TPWD) have indicated relatively large numbers of ducks wintering on
livestock ponds (i.e., stock tanks) in the Oak Woods and Blackland Prairies Ecological
Regions (Gould 1975) of northeastern Texas. From 1997 to 2011, occupancy
rates (i.e., ponds occupied by ≥1 duck) of small ponds (<0.81 h a) ranged from 11–
26%, and the estimated number of ponds increased from 277,890 to 299,583, while
occupancy rates of medium-sized ponds (0.81–16.19 ha) ranged from 32–51%. Due
to ongoing drought during the latter portion of this reporting period, the number of
medium-sized ponds decreased from 34,835 in 1997 to 23,789 in 2011. During the
same period (1997 to 2011), estimated numbers of ducks using these ponds ranged
from 458,167 (2009) to 1,159,874 (2010), and the 15-year average was 759,069.
The 3 most abundant species were Anas platyrhynchos L. (Mallard), A. strepera L.
(Gadwall), and Aythya collaris Donovan (Ring-necked Duck) (mid-winter waterfowl
surveys, 1997–2011; TPWD, Austin, TX, unpubl. data).
In the northern United States, natural prairie wetlands are important to breeding
waterfowl (Ball et al. 1995, Rumble and Flake 1983, Svingen and Anderson
1998). In similar habitats in the southern United States, natural wet-dry cycles
1Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University,
Nacogdoches, TX. 75962. Current address - Texas Parks and Wildlife Department, 11942
FM 848, Tyler, TX. 75707. 2Arthur Temple College of Forestry and Agriculture, PO Box
6109, Stephen F. Austin State University, Nacogdoches, TX 75962. *Corresponding author
- wconway@sfasu.edu.
C.D. Mason, R.M. Whiting, Jr., and W.C. Conway
2013 Southeastern Naturalist Vol. 12, No. 4
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drive plant and food production, thus providing key elements used by waterfowl
during winter. Several studies have documented that wintering waterfowl
typically use these habitats for feeding and loafing (Lee 1985, Quinlan and Baldassarre
1984). Particularly in Texas, livestock ponds may provide regionally
important habitats during periods of extended drought. Waterfowl also use these
ponds to escape hunting and other pressures commonly encountered on larger
public reservoirs (see Crook et al. 2009). In northeast Texas, most livestock
ponds are privately owned and experience little or no hunting pressure. Although
small in size, these habitats may provide important habitat for waterfowl wintering
in the region. In contrast to natural precipitation-filled prairie wetlands,
livestock ponds have not received attention as potentially useful waterfowl
habitats during winter. To address this information gap, we quantified diurnal
time-activity budgets of Mallards, Gadwalls, and Ring-necked Ducks wintering
on livestock ponds in the Blackland Prairies Region of Texas.
Field Site Description
This research was conducted in the Blackland Prairies Ecological Region of
Texas (Gould 1975) on privately owned livestock ponds in Fannin and Hopkins
counties in the very northern portion of the Blackland Prairies Region; Fannin
County abuts the Red River and Oklahoma. Mean annual precipitation in the northern
portion of the region is 100 cm, with the majority occurring during spring and
summer, although amounts and distribution vary among months and years. Winters
are generally mild with short periods of cold, wet weather during and following
passage of cold fronts. The average frost-free season is March 15–November 17
(NRCS 2008). Due to climate, soils, and topography (i.e., flat to gently rolling hills;
Gould 1975), land use is dominated by rowcrop agriculture and both improved
and native pastures (NRCS 2008): <1% of the original vegetation and ephemeral
wetlands remain regionally (TPWD 2005). In areas around our study ponds, the
primary land use was cattle grazing.
Methods
We located potential study-site livestock ponds using ground surveys in December
1999 and 2000. We defined potential study-site ponds as those 1–20 ha
in size, containing both surface water and the presence of ducks. Our choice of
specific livestock ponds as study-sites was ultimately dependent upon landowner
permission for access. We obtained access to 46 potentially suitable privately
owned livestock ponds. All study-site ponds were <3 m deep, and typically
contained emergent plants along the margins including Rumex spp. (docks), Polygonum
spp. (knotweeds), and Eleocharis spp. (spike-rushes), as well as the
floating-leaved aquatic species Nelumbo lutea Willd. (American Lotus), Ceratophyllum
demersum L. (Coontail) and Lemna minor L. (Common Duckweed). We
erected observation blinds prior to behavior sampling in early January 2000 and
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2013 Southeastern Naturalist Vol. 12, No. 4
2001; blinds were positioned to minimize disturbing birds as observers arrived
prior to sampling.
We quantified time-activity budgets for Mallards, Gadwalls, and Ring-necked
Ducks on 25 weekend days from 6 January–11 March 2000, and 10 weekend days
from 9 January–25 February 2001. We used focal-individual sampling (Bergan et
al. 1989, Crook et al. 2009, Turnbull and Baldassarre 1987) to collect behavior
data during 3 diurnal periods (morning: sunrise–1030 h; midday:1031–1400 h;
and afternoon: 1431 h–sunset; Bergan et al. 1989, Dwyer 1975, Lee 1985). We
recorded the following behaviors at 15-second intervals for 5 minutes: (1) locomotion
(i.e., swimming, walking, or flying); (2) resting (i.e., sleeping or loafing) on
land; (3) resting on water; (4) comfort (i.e., body maintenance, including preening
and bathing); (5) courtship (i.e., pair bonding displays, copulation, head-pumping);
(6) agonistic (i.e., bill threats, chasing, and any other aggressive behaviors);
(7) alert (i.e., cessation of all activities, assumption of upright posture); (8) surface
feeding (i.e., feeding without tipping); (9) subsurface feeding (i.e., feeding by tipping
or diving); and (10) land feeding (i.e., feeding out of water) (Crook et al. 2009,
Jorde et al. 1984, Paulus 1984, Quinlan and Baldassarre 1984, Rave and Cordes
1993, Turnbull and Baldassarre 1987). A total of 5 observers collected behavior
data during this study. Prior to data collection, observers trained together by watching
domesticated Mallards on the Stephen F. Austin State University campus, until
all observers were consistently able to correctly identify and classify each behavior.
We randomly selected ponds for data collection on a given sampling day. Observers
arrived at selected blinds 30 min before sunrise; if no focal species were
present on a pond 1 h after sunrise, the observer moved to the nearest study site
pond containing focal species. If >2 ducks were present, the observers began sampling
the individual nearest the center of the group (Bergan et al. 1989, Rave and
Baldassarre 1989, Turnbull and Baldassarre 1987). If only a single pair of ducks
was present, the observers alternated recording behaviors for each individual.
Likewise, if only a single individual was present, the observer continued to record
that duck’s behavior. If a focal individual was lost from view or left the pond prior
to the termination of the 5-min observation period, we terminated that sample, selected
a new individual, and initiated a new observation period. After each 5-min
observation period, the observer rested for 5 min, selected another individual, and
began a new observation period. Each observer recorded all of his observations on
standardized data sheets and entered the data into spreadsheets.
During data collection, we instructed observers to record behaviors throughout
the entire day. Consequently, there were instances in which observers repeatedly
recorded behaviors on specific individuals. To prevent inflating sample sizes by
repeatedly using data from the same individual birds and to maintain temporal independence
among focal samples (the experimental unit in this study), we randomly
selected a single focal sample for any individual during a given diurnal period (i.e.,
morning, midday, afternoon); thus, in our analysis we included no more than 3 focal
samples on a specific duck each day. All other data were censured.
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Data analysis
We quantified individual time-activity budgets by calculating the proportion
(%) of each behavior recorded during each 5-min focal sample (i.e., proportion
of 20 instantaneous behaviors recorded at 15-sec intervals). We used a factorial
multivariate analysis of variance (MANOVA) to examine differences in behaviors
among species, between sexes, among diurnal periods, and between years (i.e.,
2000 and 2001). We used MANOVA (Crook et al. 20009, Speights and Conway
2009) because individual behaviors within a focal sample are not independent. If
differences occurred (P < 0.05) in MANOVA, we used univariate analysis of variance
(ANOVA), followed by least squares mean separation if differences (P < 0.05)
occurred during ANOVAs (Crook et al. 2009, Speights and Conway 2009).
Results
Due to the consistent presence of focal species, we collected behavior data on
8 of the 46 potentially available study site ponds; all were classified as small or
medium-sized. A total of 676 focal samples were collected for Mallards (n = 281),
Gadwalls (n = 251), and Ring-necked Ducks (n = 144), from 51 hours of focal
observations. Ring-necked Duck behavior data were only collected in 2001. Behaviors
varied among species (Wilks’ λ = 0.54; df = 18, 1196; P < 0.001), though
all 3 species spent considerable time feeding (32–38%), locomoting (24–47%),
and resting (10–36%) (Table 1). For both years combined, Mallards and Gadwalls
spent approximately a third of their time feeding, as did Ring-necked Ducks in 2001
(Table 1). As expected, Ring-necked Ducks spent more time subsurface feeding
(31%) than either Mallards (8%) or Gadwalls (9%), both of which spent 26–29%
of their time surface feeding. In sum, all 3 species spent 32–37% of their time in
feeding behaviors (Table 1). Mallards and Ring-necked Ducks generally fed in localized
areas for extended periods of time, whereas Gadwalls normally fed while
Table 1. Means (%), Standard Errors (SE), and F and P values resulting from univariate analysis of
variance of wintering Mallard, Gadwall, and Ring-necked Duck behaviors measured on livestock
ponds in northeast Texas, 6 January–11 March 2000 and 9 January–25 February 2001. Means followed
by the same letter within the same row are not different (P > 0.05).
Mallard Gadwall Ring-necked Duck
(n = 218) (n = 251) (n = 144)
Behavior Mean SE Mean SE Mean SE F P
Locomotion 27 B 1.9 47 A 1.4 24 B 2.0 63.3 <0.001
Resting on land 5 A 1.4 2 B 0.7 <1 B 0.4 3.9 0.019
Resting on water 19 B 2.1 8 C 0.9 35 A 2.5 63.5 <0.001
Comfort 8 A 1.3 8 A 1.1 8 A 1.3 0.1 0.981
Courtship 1 A 0.3 <1 B <0.1 <1 B 0.1 6.1 0.002
Agonistic <1 A <0.1 <1 A <0.1 <1 A 0.2 0.7 0.507
Alert <1 A 0.2 <1 B <0.1 <1 B 0.2 12.6 <0.001
Surface feeding 29 A 2.4 26 A 1.5 1 B 0.4 44.9 <0.001
Subsurface feeding 8 B 1.3 9 B 1.0 31 A 2.1 47.1 <0.001
Feeding on land 1 A 0.5 <1 B 0.1 0 B 0.0 5.8 <0.001
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2013 Southeastern Naturalist Vol. 12, No. 4
locomoting. Resting and comfort behaviors were more frequently noted in Ringnecked
Ducks, which spent nearly 45% of their cumulative time in these behaviors
(Table 1). In contrast, Gadwalls spent only 17% of their cumulative time in these
behaviors (Table 1).
There was a species by year interaction (Wilks’ λ = 0.86; df = 9, 598; P < 0.001);
all subsequent analyses were performed within each species. Mallard behaviors
varied between years (Wilks’ λ = 0.73; df = 9, 203; P < 0.001), but were similar
between sexes (Wilks’ λ = 0.97; df = 9, 203; P = 0.791) and among time periods
(Wilks’ λ = 0.88; df = 18, 406; P = 0.069). Subsequent analyses for Mallards were
performed within each year, because behaviors were similar (P > 0.05) between
sexes, among time periods, and between paired and unpaired individuals for both
2000 and 2001. Variation in Mallard activity budgets was driven exclusively by
differences between years; Mallards spent over twice as much time feeding in
2000 (48%) as in 2001 (19%); almost 60% their time was dedicated to comfort and
resting behaviors in 2001 (Table 2). Similarly, Gadwall behaviors varied between
years (Wilks’ λ = 0.70; df = 9, 236; P < 0.001), but not between sexes (Wilks’ λ =
0.96; df = 9, 236; P = 0.276) or among time periods (Wilks’ λ = 0.90; df = 18, 472;
P = 0.157). Subsequent analyses were performed within each year for Gadwall
because behaviors were similar (P > 0.05) between sexes, among time periods, and
between paired and unpaired individuals for both 2000 and 2001. Similar to Mallards,
variation in Gadwall activity budgets was driven exclusively by differences
between years; Gadwalls spent similar time locomoting (42–49%) each year, but
spent more than twice as much time surface feeding in 2001 (Table 3). Analyses for
Ring-necked Ducks were performed within 2001 only. As with the other species,
Ring-necked Duck behaviors were similar among time periods (Wilks’ λ = 0.84;
df = 16, 262; P = 0.107). Although overall behaviors varied (Wilks’ λ = 0.88; df =
8, 131; P = 0.041) between sexes and between paired and unpaired Ring-necked
Ducks (Wilks’ λ = 0.88; df = 16, 232; P = 0.013), no individual behavior varied (P
> 0.05) in subsequent ANOVAs (Table 4).
Table 2. Means (%), Standard Errors (SE), and Type III F and P values resulting from univariate
analysis of variance of wintering Mallard behaviors measured on livestock ponds in northeast Texas,
6 January–11 March 2000 and 9 January–25 February 2001. Means followed by the same letter within
the same row are not different (P > 0.05).
2000 (n = 148) 2001 (n = 70)
Behavior Mean SE Mean SE F P
Locomotion 30A 2.3 21B 2.9 4.0 0.047
Resting on land 4A 1.5 8A 2.9 1.9 0.166
Resting on water 11B 1.9 37A 4.6 44.8 <0.001
Comfort 5B 1.3 14A 2.9 8.1 0.005
Courtship 1A 0.4 <1A 0.5 0.4 0.538
Agonistic <1A 0.1 <1A 0.0 2.2 0.139
Alert 1A 0.3 1A 0.3 0.2 0.627
Surface feeding 35A 3.0 17B 3.4 14.2 <0.001
Subsurface feeding 11A 1.9 1B 0.6 13.0 <0.001
Feeding on land 2A 0.7 <1A 0.1 3.1 0.081
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2013 Southeastern Naturalist Vol. 12, No. 4
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Discussion
As with most other wintering waterfowl activity-budget studies (Clark and
Whiting 1994, Crook et al. 2009, Paulus 1984), behaviors of all 3 focal species were
dominated by feeding, locomoting, and resting/comfort activities (Table 5). Combined,
these activities comprised >95% of all behaviors, and in sum, the activity
budgets we documented do not deviate dramatically from other published wintering
waterfowl activity-budgets, although time spent locomoting by Gadwalls was
greater than others have reported (Table 5). Paulus (1988) estimated that nonbreeding
waterfowl should allocate most of their time to feeding and resting (70–80%),
with locomoting, and non-resting comfort behaviors, dominating the remainder
of the time. However, locomoting alone exceeded 20% for each species’ activity
budget in this study. Clearly, our focal species invest more time locomoting and
Table 4. Means (%), Standard Errors (SE), and Type III F and P values resulting from univariate
analysis of variance of wintering Ring-necked Duck behaviors measured on livestock ponds in northeast
Texas, 9 January–25 February 2001. Means followed by the same letter within the same row are
not different (P > 0.05).
Males (n = 116) Females (n = 28)
Behavior Mean SE Mean SE F P
Locomotion 25 A 2.3 23 A 2.3 0.1 0.833
Resting on land 2 A 1.9 0 A 0.0 3.9 0.051
Resting on water 28 A 6.0 37 A 2.8 1.9 0.175
Comfort 13 A 4.4 7 A 1.3 2.6 0.107
Courtship <1 A 0.4 <1 A 0.1 2.1 0.148
Agonistic 0 A 0.0 <1 A 0.3 0.1 0.734
Alert 2 A 0.6 <1 A 0.2 2.2 0.140
Surface feeding 2 A 1.4 1 A 0.3 0.9 0.333
Subsurface feeding 29 A 5.4 31 A 2.3 0.1 0.760
Feeding on land 0 0.0 0 0.0 na na
Table 3. Means (%), Standard Errors (SE), and Type III F and P values resulting from univariate
analysis of variance of wintering Gadwall behaviors measured on livestock ponds in northeast Texas,
6 January–11 March 2000 and 9 January–25 February 2001. Means followed by the same letter within
the same row are not different (P > 0.05).
2000 (n = 184) 2001 (n = 67)
Behavior Mean SE Mean SE F P
Locomotion 49A 1.7 42A 2.6 3.3 0.071
Resting on land <1B 0.5 5A 2.2 6.9 0.009
Resting on water 8A 1.1 6A 1.3 2.4 0.120
Comfort 10A 1.4 3B 1.0 10.0 0.002
Courtship <1A 0.1 0A 0.0 1.1 0.304
Agonistic <1A 0.1 <1A 0.1 3.7 0.054
Alert <1A 0.1 <1A 0.1 0.1 0.716
Surface feeding 19B 1.5 42A 3.0 51.7 <0.001
Subsurface feeding 12A 1.2 1B 0.6 22.1 <0.001
Feeding on land 0A 0.0 <1A 0.5 1.5 0.221
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2013 Southeastern Naturalist Vol. 12, No. 4
comparatively less time feeding and/or resting than waterfowl in some other areas
and habitats (Table 5). Reasons for these high rates of locomoting are unclear. Vehicular
noise and gunshots were absent at our sites, and livestock did not use the
ponds. As such, anthropogenic disturbances from boating, fishing, or hunting, all of
which are often cited for increasing locomotion behaviors for wintering waterfowl
within the region (Crook et al. 2009), did not influence behavio rs in this study.
Ring-necked Ducks appeared to be relatively undisturbed, yet their behaviors,
including locomoting, were almost identical to those recorded by Crook et al.
(2009) on large (6800–75,000 ha) eastern Texas reservoirs (Table 5), where boat
traffic apparently affected behaviors. In other regional studies, Mallards in a 728-
ha bottomland hardwood forest spent almost 50% more time locomoting (Clark
and Whiting 1994) than did birds in our study, which invested almost twice as
much time in that activity than did Mallards in the Texas Panhandle (Lee 1985).
Locomoting values in Lee’s (1985) study were very similar to those from Nebraska
(Jorde et al. 1984) and Alabama (Turnbull and Baldassarre 1987) (Table 5). Thus,
mechanisms driving elevated rates of locomotion seem to be inconsistent among
studies, and may reflect responses to other, poorly defined cues.
For Gadwalls, locomotion was the primary activity (47%) in this study, whereas
it comprised only minor proportions of Gadwall activity-budgets in Louisiana
(13%) and North Carolina (5%) (Table 5). In fact, our Gadwall locomotion estimate
is greater than that found for any wintering waterfowl study (Paulus 1988:137–138).
Consequently, Gadwalls in northeastern Texas spent much less time feeding (36%)
Table 5. Summary of diurnal time-activity budgets of wintering Mallards, Gadwalls, and Ring-necked
Ducks in the United States.
BehaviorA
Location Feeding Resting Locomoting Other Reference
Mallard
Nebraska 35 28 13 18 Jorde et al. (1984)
Alabama 21 44 13 14 Turnbull and Baldassarre (1987)
East Texas 20 22 43 13 Clark and Whiting (1994)
Texas Panhandle 26 39 13 12 Lee (1985)
Northeastern Texas 38 24 27 8 This study
Gadwall
North Carolina 75 17 5 3 Hepp (1972)
North Dakota 70 8 8 9 Dwyer (1975)
Louisiana 64 11 11 14 Paulus (1984)
Northeastern Texas 35 10 47 8 This study
Ring-necked Duck
FloridaB 35 24 17 15 Hohman (1984)
Mississippi 36 34 16 13 Christopher and Hill (1988)
South CarolinaB 44 20 18 7 Bergan et al. (1989)
East Texas 30 37 24 7 Crook et al. (2009)
Northeastern Texas 32 35 24 8 This study
APercentage of time performing individual behavior.
BBehaviors approximated from figures.
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than those in Louisiana (64%) and North Carolina (75%). Although Paulus (1988)
noted that, for wintering waterfowl, time spent feeding and resting are usually inversely
related, and our results support this notion for Mallards and Ring-necked
Ducks, this was not the case for our observations of Gadwalls. In fact, our Gadwall
data suggest that feeding was inversely related to locomoting rather than resting,
and our estimated time spent resting (10%) is at the bottom of the range (10–50%)
for nonbreeding Anatids (Paulus 1988).
Our data collection protocol may have underestimated feeding time and over-estimated
locomoting time by Gadwalls, as they frequently fed by dabbling or filtering
as they swam, or by occasionally tipping for a few seconds and then moving along.
Gadwalls rarely performed extended feeding bouts, unlike in many other dabblingduck
studies, that described individuals specifically gathering or consuming foods
(Paulus 1982). However, our locomotion estimates were similar between years, even
when specific foraging behaviors (i.e., surface vs. subsurface) changed dramatically
between years (see Table 3), indicating that locomoting was in fact a dominant
behavior for Gadwalls using these livestock ponds. Interestingly, Gadwall feeding
behavior was more similar to that of Aix sponsa L. (Wood Duck) (Clark and Whiting
1994, Drobney and Fredrickson 1979) than typical Gadwall feeding behavior described
by other researchers (Dwyer 1975, Paulus 1982). Such behavioral similarities
to Wood Ducks have not been previously reported. Gadwalls were relatively widely
distributed and commonly observed on our study-site ponds, and it is possible that
they were feeding elsewhere, primarily at night. No ducks were ever present on study
ponds when observers arrived before daylight, and all always left by dark. Nocturnal
feeding behavior is often cited as a response to hunting pressure or other disturbances
(see Korschgen and Dahlgren 1992). Therefore, all 3 focal species, but especially
Gadwalls, may have been pursuing nocturnal foraging opportunities elsewhere, and
used the livestock ponds diurnally for supplemental foraging. Future work should examine
food availability and quality to more clearly examine the relationship between
foraging behaviors and nutritional food values to more clearly characterize the importance
of regional livestock ponds for wintering waterfowl.
Similar to other studies of Mallards (Turnbull and Baldassarre 1987), Gadwalls
(Paulus 1984), and Ring-necked Ducks (Crook et al. 2009, Hohman 1984), behaviors
were similar between sexes for all 3 species. Perhaps activity budgets were
similar because 1) both sexes have similar nutrient requirements (Hohman 1984,
Paulus 1984), and 2) livestock-pond quality was not impacting activity budgets
between sexes or between paired and unpaired individuals. Although some studies
have noted between-sex differences (Bergan et al. 1989, Clark and Whiting 1994,
Jorde et al. 1984), such differences may be a result of intersexual aggression and
male dominance (Hohman 1984) or that females, which are smaller than males, are
at a thermal disadvantage (Bergan et al. 1989). However, agonistic and courtship
behaviors were infrequently observed during this study (<1% for all species).
Variation in activity budgets among diurnal periods is inconsistent among studies;
some researchers have found variation (Clark and Whiting 1994, Hohman
1984, Paulus 1984), and others have not (Turnbull and Baldassarre 1987). There is
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2013 Southeastern Naturalist Vol. 12, No. 4
no strong, consistent pattern of daily activities among species or studies. Generally,
Mallards rested in the morning and fed in the afternoon (Clark and Whiting 1994,
Jorde et al. 1984), whereas Gadwalls fed early and late and rested at midday (Paulus
1984). Ring-necked Ducks in Florida were most active (feeding, locomoting, alert)
in morning (Hohman 1984), but those in South Carolina fed throughout the day, and
rested and locomoted most in the afternoon (Bergan et al. 1989). No such diurnal
variation was observed in this study, where activity budgets were consistent among
all time periods.
Yearly variation in activity budgets is not uncommon, because changing
habitat conditions and weather patterns can dramatically influence behavior
from year to year. In this study, differences between years was the primary factor
influencing variation in activity budgets for Mallards and Gadwalls; we contend
that this factor was strongly related to water availability during the study. In
1999, the study area received only 71 cm of rainfall, compared to 139 cm in 2000;
temporal distribution of the precipitation was also a factor in altering water levels
in the livestock ponds during our study. There were 30.0 cm of precipitation during
November–December 1999 and January–February 2000, whereas 83 cm of
precipitation were experienced during the same months in 2000–2001—nearly
a 3-fold difference in precipitation (Weather Station Records, US Army Corps
of Engineers, Sulphur Springs, TX, unpubl. data). Precipitation in late fall and
early winter of 2000–2001 flooded pastures and agricultural fields, and allowed
ducks to disperse to these areas as well as to recently flooded wetlands adjacent
to nearby reservoirs. Although numbers of focal samples collected in 2001 were
<50% of those recorded in 2000, these decreases do not necessarily reflect a decrease
in the number of waterfowl wintering regionally. In fact, there were more
Mallards and Gadwalls observed during mid-winter (January) waterfowl surveys
in 2001 than 2000 in the Oak Woods and Blackland Prairie Ecoregions —2000:
Mallards 284,907; Gadwalls 203,484; 2001: Mallards 453,762, Gadwalls 245,126
(mid-winter waterfowl survey 2000, 2001; TPWD, Austin, TX, unpubl. data). We
presume that Gadwalls and Mallards were using other wetland types more frequently
than livestock ponds in 2001.
We assume that the birds moved to other potentially suitable habitats, and that
such movements may have accounted for the changes in Mallard and Gadwall
behaviors in 2001. In 2000, Mallards spent nearly 50% of their time in feeding behaviors,
but in 2001, they spent <20% of their time feeding and nearly 50% of their
time resting (Table 2). Conversely, Gadwalls more than doubled the amount of time
they spent surface feeding from 2000 to 2001, and increased locomotion from 42 to
49% (Table 3). These differences in Mallard and Gadwall feeding behaviors may
be related to the 3-fold increase in precipitation from 2000 to 2001. The drought of
1999 and early 2000 reduced water levels in the ponds and nearby reservoirs, and
in 2000, the only water available for ducks in Hopkins and Fannin counties was in
ponds and reservoirs; thus, potential feeding sites were limited, and the birds were
concentrated. In 2001, Mallards were widely distributed, and as we traveled between
study sites searching for focal species, we commonly saw Mallards feeding
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in flooded fields and pastures and large flocks of Gadwalls and Ring-necked Ducks
on nearby reservoirs.
Mallards typically prefer shallow-water feeding-sites such as the flooded fields
and pastures noted in 2001. For example, Mallards wintering in Alabama foraged in
shallow impoundments and often made evening feeding flights to flooded agricultural
fields (Turnbull and Baldassarre 1987). Similar to this study, Mallards spent
time in non-feeding behaviors on a deep impoundment and a river (Turnbull and
Baldassarre 1987). In the Texas Panhandle, Mallards spent more time feeding in
shallow-water terraced pits than in steep-sided pits and open-water lakes combined,
although they spent approximately the same amount of time resting in each of the
3 habitat types (Lee 1985). In 2001, the increased surface feeding that we observed
for Gadwalls may have been due to increased food availability brought by run-off
into recently inundated areas around the ponds; we rarely observed subsurface
feeding in 2001. Subsurface feeding requires more energy and, with increased food
supply, may simply not have been necessary (sensu Goldstein 1988, Lovvorn and
Gillingham 1996). Similarly, vegetation available for subsurface feeding in 2000
may not have been available in 2001 due to increased water depths and/or changes
in plant species composition. Increased food availability in 2001 may have resulted
in Gadwalls investing more time in feeding and resting on land, thus reducing time
spent incomfort activities.
Regional livestock ponds clearly provide wintering habitats for our focal species,
as evidenced from mid-winter surveys, where >500,000 individuals of our
focal species typically occur in the Oak Woodlands and Blackland Prairie Ecoregions
during winter. However, Anas clypeata L. (Northern Shoveler) and A. crecca
Gmelin (Green-winged Teal) also regularly used ponds, as did 9 other species (Mason
2002). Understanding how ducks use various habitats is especially important
before making decisions about how to create and manage man-made waterfowl habitat,
which are usually developed as shallow-water features. In contrast, livestock
ponds are designed as deeper water bodies. However, our results suggest that small
livestock ponds are also necessary for diurnal foraging and resting, and may be
critical in dry years, when natural or man-made shallow-water habitats are limited
or absent on the landscape. To more clearly characterize the regional value of these
ponds, future work should focus upon waterfowl feeding habits, livestock-pond
food production, and nutritive quality of those items as related 1) to water level, and
2) occupancy by wintering waterfowl. Such work should facilitate development of
more specific conservation and management guidelines for these regional wintering
waterfowl habitats.
Acknowledgments
This study was funded by the Arthur Temple College of Forestry and Agriculture,
Stephen F. Austin State University. We thank S. Cordts, C. Frentress, W. Johnson, K.
Kraai, D. Morrison, and B. Sullivan for their ideas and assistance. R. Mangham, J. Laing,
S. Locke, and S. Crook assisted with gathering behavioral data. S. Leeper assisted with
manuscript preparation.
767
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2013 Southeastern Naturalist Vol. 12, No. 4
Literature Cited
Ball, I., R. Eng, and S. Ball. 1995. Population density and productivity of ducks on large
grassland tracts in north-central Montana. Wildlife Society Bulletin 23:767–773.
Bergan, J.F., L.M. Smith, and J.J. Mayer. 1989. Time-activity budgets of diving ducks
wintering in South Carolina. Journal of Wildlife Management 53:769–776.
Christopher, M.W., and E.P. Hill. 1988. Diurnal activity-budgets of nonbreeding waterfowl
and coots using catfish ponds in Mississippi. Proceedings of the Annual Conference of
the Southeastern Association of Fish and Wildlife Agencies 42:520–527.
Clark, H.B., and R.M. Whiting, Jr. 1994. Time budgets of Mallards and Wood Ducks
wintering in a flooded bottomland hardwood forest. Proceedings of the Annual Conference
of the Southeastern Association of Fish and Wildlife Agencies 48:22–30.
Crook, S.L., W.C. Conway, C.D. Mason, and K.J. Kraai. 2009. Winter time-activity budgets
of diving ducks on eastern Texas reservoirs. Waterbirds 32:548–558.
Drobney, R.D., and L.H. Fredrickson. 1979. Food selection of Wood Ducks in relation to
breeding status. Journal of Wildlife Management 43:109–120.
Dwyer, T.J. 1975. Time budgets of breeding Gadwalls. Wilson Bulletin 87:335–343.
Goldstein, D.L. 1988. Estimates of daily energy expenditures in birds: The time-energy
budget as an integrator of laboratory and field studies. American Zoologist 28:829–844.
Gould, F.W. 1975. The Grasses of Texas. Texas Agricultural Experiment Station, College
Station, TX. 112 pp.
Hepp, G.R. 1982. Behavioral ecology of waterfowl (Anatini) wintering in coastal North
Carolina. Ph.D. Dissertation. North Carolina State University, Raleigh, NC. 155 pp.
Hohman, W.L. 1984. Diurnal time-activity budgets of Ring-necked Ducks wintering in
Central Florida. Proceedings of the Annual Conference of the Southeastern Association
of Fish and Wildlife Agencies 38:158–164.
Jorde, D.G., G.L. Krapu, R. Crawford, and M.A. Hay. 1984. Effects of weather on habitat
selection and behavior of Mallards wintering in Nebraska. Condor 86:258–265.
Korschgen, C.E., and R.B. Dahlgren. 1992. Human disturbances of waterfowl: Causes, effects,
and management. Fish and Wildlife Leaflet 13.2.15.
Lee, S.D. 1985. A time-budget study of Mallards on the Texas High Plains. M.Sc. Thesis.
Texas Tech University, Lubbock, TX. 32 pp.
Lovvorn, J.R., and M.P. Gillingham. 1996. Food dispersion and foraging energetics: A
mechanistic synthesis for field studies of avian benthivores. Ec ology 77:435–451.
Mason, C.D. 2002. Diurnal time budgets of Mallards and Gadwalls wintering on livestock
ponds in Northeast Texas. M.Sc. Thesis. Stephen F. Austin State University, Nacogdoches,
TX. 62 pages.
Natural Resource Conservation Service (NRCS). 2008. Ecological Site Description–Texas
Blackland Prairie, Northern Part. Available online at http://esis.sc.egov.usda.gov/
ESDReport/ fsreport.aspx?id=RO86AY196TX&rptLevel=all&a. Accessed 6 June 2011.
Paulus, S.L. 1982. Feeding ecology of Gadwalls in Louisiana in winter. Journal of Wildlife
Management 46:71–79.
Paulus, S.L. 1984. Activity of nonbreeding Gadwalls in Louisiana. Journal of Wildlife
Management 48:371–380.
Paulus, S.L. 1988. Time-activity budgets of nonbreeding Anatidae: A review. Pp. 135–152,
In M.W. Weller (Ed.). Waterfowl in Winter. University of Minnesota Press, Minneapolis,
MN. 624 pp.
Quinlan, E.E., and G.A. Baldassarre. 1984. Activity budgets of nonbreeding Green-winged
Teal on playa lakes in Texas. Journal of Wildlife Management 48:838–845.
C.D. Mason, R.M. Whiting, Jr., and W.C. Conway
2013 Southeastern Naturalist Vol. 12, No. 4
768
Rave, D.P., and G.A. Baldassarre. 1989. Activity budget of Green-winged Teal wintering in
coastal wetlands of Louisiana. Journal of Wildlife Management 53:753–759.
Rave, D.P., and C.L. Cordes. 1993. Time-activity budget of Northern Pintails using nonhunted
rice fields in Southwest Louisiana. Journal of Field Orni thology 64:211–218.
Rumble, M., and L. Flake. 1983. Management considerations to enhance use of stock ponds
by waterfowl broods. Journal of Range Management 36:691–694.
Speights, J.R., and W.C. Conway. 2009. Wintering Yellow-bellied Sapsucker time-activity
budgets in East Texas bottomland hardwood forests. The Wilson Journal of Ornithology
121:593–599.
Svingen, D., and S.H. Anderson. 1998. Waterfowl management on grass-sage stock ponds.
Wetlands 18:84–89.
Texas Parks and Wildlife Department (TPWD). 2005. Texas Comprehensive Wildlife Conservation
Strategy 2005–2010. Austin,TX.
Turnbull, R.E., and G.A. Baldassarre. 1987. Activity budgets of Mallards and American
Wigeon wintering in East-central Alabama. Wilson Bulletin 99:457–464.