Mottled Duck Telemetry Report - 1
MOTTLED DUCK TELEMETRY REPORT
Associate Research Scientist
Fish and Wildlife Research Institute
Florida Fish and Wildlife Conservation Commission
August 10, 2009
2009 Mottled Duck Telemetry Report - 2
Avian Research Subsection
Wildlife Research Section
Fish and Wildlife Research Institute
Project: 9220 251 1000 B Mottled duck telemetry
Study Duration: March 2008 – March 2011
Principal Investigator: Ronald R. Bielefeld, Florida Fish and Wildlife
Conservation Commission, 544 Jay Street, Sebastian,
Assistants: Jamie Feddersen, Florida Fish and Wildlife
Conservation Commission, 3200 T.M. Goodwin Rd.,
Fellsmere, Florida, 32948
Prepared by: Ronald R. Bielefeld
Date prepared: 31 July 2009
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Abstract: On 7-9 September, 2008 FWRI personnel with assistance from Division of
Hunting and Game Management, South Florida Water Management District, University of
Florida Veterinary School, and U.S. Department of Agriculture personnel captured and radio-
marked 47 female mottled ducks in the Everglades Agricultural Area (EAA). During January
through March 2009 we attempted to capture 50 adult females from the urban/suburban area in
and around West Palm Beach, FL. We caught and radio-marked 16 birds. Starting in September
with the radio-marking of the birds from the EAA we monitored the habitat use, movements, and
survival of the radio-marked birds. The mean number of locations collected for each bird thus
far, is 52. Most rural caught ducks used Storm Water Treatment Areas, agricultural
impoundments, and pasture ponds in the fall and early winter. In late January, however, many
birds began using marshes associated with the Everglades and Lake Okeechobee. By mid-March
nearly all of the ducks were using those areas. Birds began leaving the Everglades in June, most
returning to the EAA with a few moving west onto pasture ponds. This annual movement pattern
appears to be driven by surface water availability. Urban caught birds stayed in urban/suburban
areas almost exclusively. Urban birds used man-made pond and ditch habitats. Their habitat use
and movement patterns also were influenced by changing availability of surface water. The
home ranges of rural birds averaged 1,885 km2 versus only 16 km2 for urban birds. There have
been 19 mortalities, two of which were urban ducks. We began to detect nesting attempts in
early April and our last nest hatched in mid-July. We found only 11 nests. Six hatched, three
were depredated, one was abandoned and one mowed. Seven of 11 nests were in urban areas
and initiated by urban caught birds.
The Florida mottled duck (Anas fulvigula fulvigula) is a unique subspecies of the mottled
duck (Anas fulvigula) found only in peninsular Florida (McCracken et al. 2001). Florida mottled
ducks have an intrinsic aesthetic value, are highly prized as a game bird (Chamberlain 1960), and
are a defining member of the unique suite of species characteristic of south Florida. Natural and
man-made wetlands associated with Lake Okeechobee, the Everglades Agricultural Area (EAA),
the Kissimmee River Basin (KRB), and adjacent urban/suburban areas support a large number of
mottled ducks and are considered important habitat areas for this species (Johnson et al. 1991;
Florida Fish and Wildlife Conservation Commission unpublished data). Wetlands in these areas
also support hundreds of thousands of migrant and wintering dabbling ducks on an annual basis,
most notably blue-winged teal (Anas bicolor), green-winged teal (Anas crecca), American
Wigeon (Anas Americana), Northern Pintail (Anas acuta), Gadwall (Anas strepera), and
Northern Shovelers (Anas clypeata).
Florida’s landscape continues to be altered at a staggering rate. Forty-two percent of
Florida’s dry land acres have been modified for urban and agricultural use since 1936 (The
Nature Conservancy 1991), and wetlands are continually being manipulated for such purposes as
flood control, water supply, and agriculture, as well as to achieve habitat enhancement for fish
and wildlife. These manipulations alter natural wetland systems and create artificial wetlands
such as storm water treatment areas, flooded agricultural fields, canals, ditches, and cattle ponds.
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Historically, the hydrology, flora, and fauna associated with Lake Okeechobee, the KRB, and
what is currently the EAA was dramatically altered for and by agricultural activities. These
areas also have undergone and continue to undergo dramatic changes as the result of restoration
activities associated with the Comprehensive Everglades Restoration Project, State-related
restoration, and changes in surface water management philosophies. Habitats to the east of these
areas have been significantly impacted by urbanization.
In general, little is understood about how mottled ducks use habitats associated with Lake
Okeechobee, the EAA, the KRB, and adjacent urban areas. Moreover, no data exist regarding
how they have adapted to recent landscape changes in these areas, or how these and future
changes have or will affect their ability to exist in these areas over the long term. To gain a
better understanding of the ecology of mottled ducks in south Florida and how recent and future
wetland related activities have and will affect mottled ducks in this area, I we have initiated a 3-
year study to investigate the habitat use, movements, and survival of female mottled ducks in
south Florida. This project will provide information that will allow people involved with land
management and wildlife conservation in these areas to understand better what affect a planned
habitat project will have on mottled ducks. In turn, this improved understanding will allow
managers to focus conservation efforts where they will be most effective in conserving this
STUDY AREA, OBJECTIVES, AND METHODS
The study area will be southern peninsular Florida and where ever the radio-marked birds
(1) Quantify seasonal habitat use patterns of mottled ducks.
(2) Describe/characterize, in detail, wetlands used heavily by dabbling ducks
(3) Compare heavily used wetlands to random and AHRES wetlands to Identify wetland
characteristics that influence use by dabbling ducks.
(4) Determine if surface water availability influences habitat use, movement, and survival
patterns of mottled ducks.
(5) Determine annual and season-specific survival rates for mottled ducks, and whether
they differ by year, season, and catch location (rural versus urban areas).
(6) Identify causes of female mortality and determine if they differ by year, season, and
(7) Determine relative importance of hunting mortality to annual survival of mottled
(8) Determine home ranges of females and the influence of year, season, and catch
location on movements.
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(9) Describe nesting and brood-rearing sites, and identify characteristics that influence
nest fate and female survival. Specific habitat characteristics to be investigated include
predominant vegetation type, density of cover, and size of habitat area surrounding nest
sites; distance to nearest water, distance to brood-rearing area, distance to a human
dwelling, and distance to paved road from nest sites; predominant land use surrounding
nest sites; percent cover of water and emergent vegetation on brood-rearing wetlands;
permanency of brood-rearing wetlands; distance of brood-rearing wetlands from nearest
human dwelling, paved road, and other wetlands; and size of brood-rearing wetlands.
(10) Determine nest and female success rates and if these parameter differ among years
and by catch location.
Objective 1: Identify habitat use patterns on a seasonal and annual basis.
Radio telemetry will be used to monitor habitat use by female mottled ducks throughout
their annual cycle. Each year during August and September in and around the EAA, Lake
Okeechobee, the lower KRB, and the suburban areas to the east, a total of 100 adult female
mottled ducks will be captured using night-lighting techniques. After capture, birds will be taken
to a processing site where morphological measurements will be taken, standard U.S. Fish and
Wildlife Service leg bands will be affixed, and a VHF radio transmitter implanted abdominally
(Korschgen et al. 1996). The radios will have an expected life of 13 months and a design similar
to those developed by Korschgen et al. (1995). After a recovery and observation period (12-18
hours), birds will be released at their capture site.
Immediately after release, birds will be monitored daily from trucks equipped with dual
4-element null-peak detection systems (Mech 1983) and at least weekly from an aircraft (Cessna
or similar) equipped with two 4-element Yagi antennas (Gilmer et al. 1981). For as many
locations as possible, the habitat being used will be determined and recorded, that is, a visual will
be made of the radio-marked bird. Examples of habitats to be categorized include 1) natural
marsh, 2) intensively managed marsh, 3) flooded pasture, 4) flooded EAA field, 5) prairie pond,
6) flooded prairie, 7) flooded cattle pond, 8) flooded citrus impoundment, 9) flooded
management area impoundment, 10) flooded ditch, 11) flooded canal 12) flooded rice, 13) other
flooded agriculture, 14) upland habitat, 15) everglades marsh, 16) river, 17) lake, 18) lake
Okeechobee marsh, or 19) AHRES project wetland. Additional categories will be added as
necessary to describe habitats used by radio-marked birds. These data will be analyzed to
determine which habitats are used most often (based on the proportion of individual bird’s
locations that occur within the different habitats), and if habitat use patterns vary by period of the
annual cycle, year, and bird catch location using MANOVA. Habitat use patterns of birds from
this study also will be compared to birds tracked during an earlier study of mottled duck habitat
use in the SJRB.
Objective 2: Describe/characterize, in detail, wetlands used heavily by dabbling ducks.
Radio-marked mottled ducks will be used to obtain an unbiased sample of
wetlands/wetland complexes being used heavily by dabbling ducks throughout the year. These
wetland areas will be characterized by collecting data on average depth, mean percent vegetative
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cover, predominant vegetation types, bottom make-up, water level variability, water chemistry,
distance to nearest human activity, distance to other water source, as well as other parameters.
These data will be used to build a profiles for highly productive wetlands.
Objective 3: Compare heavily used wetlands to random and AHRES wetlands to Identify
wetland characteristics that influence use by dabbling ducks.
Data collected to meet objective two will be compared to similar data collected from random
wetlands and wetlands restored by the AHRES. These comparisons will be made to elucidate
which parameters influence use of wetlands by mottled ducks and other dabbling ducks.
Moreover, these comparisons will us to evaluate the effectiveness of current AHRES wetland
enhancement practices with regard to their creating preferred habitat for dabbling ducks.
Objective 4: Determine if surface water availability influences habitat use, movement, and
survival patterns of mottled ducks and habitat use patterns of other dabbling ducks.
Fifteen to 20 water bodies (5 each with hydrologic permanency classes of temporary,
semi-permanent, and permanent) will be randomly selected from those within the study area.
These wetlands will be monitored on a weekly basis to determine if surface water is present and
to what extent the area of surface water has changed from the previous week. These data will be
included as a predictor in the analysis of habitat use, movement, and survival data to determine if
surface water availability influences these aspects of mottled duck and dabbling duck ecology.
Objective 5: calculate annual and season-specific survival rates and determine if female survival
differs among years, periods of the annual cycle, and catch location.
Radios will be equipped with a 12-hour mortality sensor. Females will be monitored
daily throughout the annual cycle to determine their status (i.e., dead or alive). Proportional
hazards regression (Cox 1972) will be used to test for differences in survival in relation to period
of annual cycle, year, and catch location.
Objective 6: identify causes of female mortality and determine if they differ by year, periods of
the annual cycle, and catch location.
When a mortality is indicated, efforts will be made to determine the cause. When
possible, carcass and radio condition will be used to assess the cause of mortalities. If the cause
of death is not obvious upon examination of the carcass, the carcass will be sent to the Southeast
Cooperative Wildlife Disease Study (University of Georgia at Athens) for necropsy.
Objective 7: Determine relative importance of hunting mortality to annual survival of mottled
All sources of mortality identified during the study will be analyzed to determine the
relative importance of each.
Objective 8: determine home ranges of females and the influence of period of the annual cycle,
year, and catch location on movements.
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Using ground and aerial techniques, point locations of females will be obtained at least
twice per week throughout the annual cycle. The annual cycle will be divided into 4 periods (1)
reproductive, (2) post-reproductive, (3) hunting season, and (4) late winter. On the ground, point
locations will be estimated using Lenth’s maximum-likelihood estimator (MLE; White and
Garrott 1990). MLEs will be calculated on site from at least 3 azimuths on a notebook computer.
From the air, point locations will be determined using a GPS.
Point locations will be used to determine if movement patterns vary among years and
between catch locations.
Objective 9: describe nesting and brood-rearing sites and identify characteristics that influence
nest fate and female survival.
Beginning in February, monitoring will focus on the identification of nest sites and
brood-rearing areas. At the time each nest is located, latitude and longitude of the site will be
determined using a Global Positioning System (GPS). Also, nest initiation and hatch date will be
estimated by candling eggs (Weller 1956), and the number of eggs in the clutch will be recorded.
If no eggs are present, another visit will be made several days later to determine the status of the
nest, and if active, estimate hatch date. For each nest site, the major plant species immediately
surrounding the nest bowl, density of nesting cover at the nest bowl and intervals of 1, 5, 10, and
20 meters from the nest bowl in the four cardinal directions will be recorded. These
measurements also will be recorded at 5 random locations in close proximity to the nest. In
addition, predominant land use within 100 meters and 1 km, distance to nearest water body,
distance to brood-rearing area for successful nests, and distance to nearest human dwelling and
paved road will be recorded.
Density of nesting cover at and near the nest bowl will be determined using a robel pole
(Robel et al. 1970). Predominant land use within 100 meters of the nest site will be determined
in the field and classified as (1) cattle production, (2) milk production, (3) citrus production, (4)
sugarcane production, (5) rice production, (6) other agriculture, (7) transportation corridor, (8)
urban development, (9) wildlife management, or (10) other. The predominant land use within 1
km will be determined using current Geographical Information System (GIS) data layers in the
lab, and will be categorized as with the 100-meter data. Distance to nearest water body, brood-
rearing area, and human dwelling, and paved road also will be determined on-site or from GIS
To determine characteristics of nest sites that influence female survival and whether a
nest is successful, proportional hazards regression (Cox 1972) will be used to test for differences
in nest fate and female survival in relation to nest site characters. To determine if females are
selecting nest sites based on vegetation height and density, paired t-tests will be used to compare
data taken at the nest bowl to those taken at the 5 random locations around the nest site. Logistic
regression models will be developed to investigate predictive abilities using aforementioned
Brood-rearing habitats will be identified by monitoring wetland use of brood-leading,
radio-marked females. Brood-rearing habitats will be characterized by recording (1) distance
from nest site, (2) size of wetland, (3) predominant vegetative types, (4) percent cover of water
2009 Mottled Duck Telemetry Report - 8
and emergent vegetation, (5) permanency class (Stewart and Kantrud 1971) of wetland, (6)
distance of wetland from nearest human dwelling and paved road, (7) distance to another
wetland, and (8) predominant land use within 1 km of the area. These data will be obtained
using a combination of GIS data and data collected at each site.
To determine characteristics of brood-rearing areas that influence female survival,
proportional hazards regression (Cox 1972) will be used to test for differences in survival in
relation to the aforementioned characters.
Objective 10: determine if nest and female success differs between years and catch location.
All nests located as described in Objective 5, and believed still to be active based on
female behavior, will be revisited shortly after the estimated hatch date to determine fate.
Proportional hazards regression (Cox 1972) will be used to test for differences in nest and female
success in relation to year and catch location.
On 7-9 September, 2008 FWRI personnel with assistance from Division of Hunting and
Game Management, South Florida Water Management District, University of Florida Veterinary
School, and U.S. Department of Agriculture personnel captured and radio-marked 47 female
mottled ducks in the Everglades Agricultural Area (EAA; Figure 1). During January through
March 2009 we attempted to capture 50 adult females from the urban/suburban area in and
around West Palm Beach, FL. We caught and radio-marked 16 birds (Figure 1). We caught our
EAA birds on flooded agricultural fields and Storm Water Treatment Area impoundments
(STAs) using night-lighting techniques from an airboat. The birds we marked in West Palm
Beach were caught using a variety of techniques including walk-in and swim-in funnel traps,
remotely triggered walk-in traps, and an air-powered cannon net. We baited trap sites using
whole kernel corn to attract birds to the site prior to setting traps. We also attempted to capture 5
birds in the Kissimmee Chain of Lakes area; however, 18-30 inches of rain from Tropical Storm
Fay flooded the basin making capture of birds impossible.
We have been tracking the birds on a daily basis since they were released. To date, we
have collected nearly 3000 locations on the 63 birds we radioed-marked for year one of the
Rural birds – Our 47 rural caught birds were using flooded agricultural fields (n=37) and
STA impoundments (n=10) when captured (Figure 2). By mid-October most of the birds had
moved off of the flooded fields and were using STAs, pasture ponds, and shallow reservoirs
associated with agriculture outside the EAA (Figures 2 and 4). However, a couple of birds
remained in the vicinity of the flooded field capture site into mid-November. They used ditch
2009 Mottled Duck Telemetry Report - 9
habitats because the fields had been drained in preparation for planting winter vegetable crops.
They both were killed. One of the birds was injured and could not fly. This bird most likely
died from malnutrition. The other bird was still molting and could not fly. She was killed by a
predator. By mid-December the vast majority of our birds were scattered throughout southern
Florida with very few using EAA habitats other than STAs (Figures 2 and 4). Use of Lake
Okeechobee marshes increased and use of pasture ponds and agricultural reservoirs continued
through mid-February. Beginning in mid-February a major shift in habitat use began. Almost
all our birds began using freshwater marsh habitats associated with Lake Okeechobee, the
Everglades, and Loxahatchee National Wildlife Refuge (Figures 2 and 5). The use of these
habitats continued until late May when the birds began using EAA flooded fields and ditches
(Figures 2 and 6). All but two of our rural caught birds used rural habitats exclusively.
Urban birds – Habitat use by our urban caught birds was much less dynamic. All but one
stayed within the urban/suburban areas near West Palm Beach. Some birds used habitats not
designated as urban (Figure 3). These habitats mostly were small wooded and grassy areas
associated with parks or natural areas within the city and suburbs (Figure 3). In general, our
urban birds used urban ponds and ditches. Periodic rain events temporarily flooded road-side
ditches and other low lying areas. It appears urban mottled ducks are birds of the moment, as
many of our birds began using these newly flooded areas very quickly, and would abandon them
just as fast as the water drained away.
Rural birds – Rural birds moved, on average, 5,494 m each time they relocated.
Distances moved were consistent from September through the end of February (the Post
Breeding, Hunting, and Late Winter periods), but increased dramatically for the period March –
July (the Reproductive periods; Figure 7). Mean home range size (Minimum Convex Polygon;
MCP) was 1,885 km2.
Urban birds – Birds using urban/suburban areas moved much shorter distances on
average when they relocated (x = 1,051 m) as compared to rural birds (Figure 7). Mean home
range (MCP) size for urban caught birds was only 16 km2.
We have not had birds marked for a full year yet, so I have not calculated survival rates;
annual or season-specific. Causes of mortalities have been difficult to determine.
Rural birds – We have had 17 (36%) rural birds die as of mid-July. Three birds died
during the Post Breeding period (September through the beginning of the hunting season), six
died during the Hunting season (late November through late January), none died during Late
Winter (end of hunting season to the beginning of March), and 11 died during the Reproductive
period (early March to mid-July).
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Urban birds – Two urban birds (13%) have died as of mid-July. Both died during the
We had high hopes going into this first nesting season that we would obtain a wealth of
information about the nesting ecology of mottled ducks in south Florida. However, only 11 nests
were found, including one renest. Of these, six attempts were made by urban birds. Overall, six
nests hatched (54%), three were depredated, one was abandoned, and one mowed over. The first
nest was discovered on 8 April and the last nest hatched on 21 July.
Rural birds – Rural nests were located in young sugarcane fields near ditches (n=3) and
Everglades sawgrass marsh (n=1). One female was discovered with a brood in an STA
impoundment, so she obviously had a nest nearby, but her nest was never found.
Urban birds – Urban nests were located in a variety of habitats including scrub (n=1),
pine/palmetto (n=1), grassy road-way medians (n=2), and decorative and natural grassy and
shrubby areas associated with housing developments (n=3). Two of the nests were within a few
feet of peoples homes. Six of 15 (40%) birds alive during the nesting period attempted a nest.
One of the birds renested.
I have not had the time to look at the wetland characterization data collected thus far in
the project. Consequently, there are no results to report at this time.
We were able to catch 47 adult female mottled in the EAA, which was just short of our
goal of 50. An approaching hurricane made catching birds more difficult than usual. We will be
catching birds in the EAA during 3 periods in the fall of 2009 instead of just one period as we
did in 2008. This should reduce the chances of weather interfering with our ability to catch the
50 birds we need.
Trapping of urban birds turned out to be more difficult than we hopped. Birds became
weary of bait traps very quickly, which resulted in us catching one bird at a time. One bird at a
time does not result in reaching the 50 bird goal very quickly, and as winter moved into spring
the number of females coming to our bait sites decreased dramatically. The end result, we only
captured 16 birds. For 2009-10 we will be doing things differently. First, we will be starting our
trapping in October instead of January, giving us more time to catch the birds we need. Second,
we will be using an air-powered cannon net. We obtained and used the cannon net once at the
very end of the trapping season in 2008-09 and caught more birds in one attempt than in all the
prior bait trapping efforts combined. Thus, we believe we will be able to catch the 50 adult
females in just a few well placed net shots.
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Going into this study we knew very little about the habitat use patterns of mottled ducks
in south Florida, but with the first year of this study nearing an end we now know quite a bit
more. It is apparent that the birds that undergo remigial molt in the EAA (our rural group of
birds) use habitats over a large area of south and even central Florida (two of our birds spent time
in southeast Osceola County) once they regain flight. Thus, it appears flooded agricultural fields
and STAs within the EAA provide important molting habitat for birds from a large part of south
Florida, not just the local area.
Where mottled ducks go and the types of habitats they use once they move off of molting
sites appears to be influenced by the availability of surface water. When the pasture/prairie
ponds and STAs were flooded (during fall and early winter) our birds used these habitats and
appeared to avoid larger marsh areas such as those associated with Lake Okeechobee and the
Everglades. However, as the dry season progressed and ponds and STAs dried up due to drought
conditions (mid-winter through early spring nesting period), birds moved to more permanent
marshes in the Everglades and to a lesser extent on Lake Okeechobee. The use of Lake
Okeechobee marshes was no surprise, as we knew mottled ducks used these marshes when
available, but the extensive use of Everglades freshwater marsh during this dry period is new and
important information. It appears increasing water levels in the Everglades during mid-May
caused our birds to abandon Everglades’s marshes and return to the EAA by early June. A
couple of birds also moved back to the pasture/prairie pond areas to the west of the EAA. It was
at this time that a few of the birds that moved back to the EAA attempted nests in early growth
sugar cane. Clutch sizes of 9-10 eggs would indicate these were first attempts, but there is really
no way of knowing for sure.
It appears that many of the birds we originally captured during remigial molt within the
EAA are returning to the same general areas to molt this year. We will know more about return
rates in September.
Our data suggest Lake Okeechobee and Everglades freshwater marshes are important
winter habitats for mottled ducks in south Florida during periods of dry conditions. However,
they also may be important to early spring reproductive success during dry years. Although we
were unable to monitor birds using the Everglades well enough to gather good nesting data, we
did determine that mottled ducks were nesting in dry Everglades marsh areas during the early
and middle part of the nesting period. We had one of our birds nesting in this habitat and we
discovered another nest while trying to monitor birds in the Everglades from airboats. This
strategy of nesting in dry marsh areas is risky because a small amount of rain can flood nests, but
it may provide mottled ducks with their best opportunity to reproduce during dry years. The
extreme amount of habitat in the Everglades probably makes it difficult for predators to find
nests and females, thus increasing nest success and female survival. The fact that we did not
have any birds die while using Everglades habitats may be evidence to that effect. However, it
also may mean that many of our birds did not attempt to nest while they were using this area.
Conversely, our data indicate that predation of nests and females in EAA habitats likely are high
during the late nesting period. We had several birds die once they returned to the EAA from the
Everglades and two out of three nests were destroyed by predators. We did observe how risky
the strategy of nesting in marsh can be, but also that it can result in success. Just one day after
the only nest we located in Everglades marsh hatched, that nest site was flooded due to heavy
2009 Mottled Duck Telemetry Report - 12
rains. I am sure many nests still active in like habitat were flooded and failed to hatch.
However, odds are, that many nests like the one we monitored also were successful.
The best thing that could happen would be for this coming fall and winter to be wet
enough to keep the pasture ponds and STAs flooded. This would allow us to determine if this
same habitat use pattern persists during wet years.
Very little indication of what killed the bird has been discovered at many of the mortality
sites. We have concluded that five of the six birds that died during the hunting season were the
result of hunters. We will be looking more closely at the mortality data to see if we can
determine the cause of more of the deaths.
I am convinced that more of our rural caught females attempted to nest than just the four
we know nested. I believe the reason we did not detect more nesting attempts was the movement
of almost all of our rural birds into the Everglades and Lake Okeechobee marshes during the
peak of nesting, which appears to have been April through early June given the high number of
mortalities that occurred during this period (10 of 19 total mortalities). During most of the peak
nesting period drought conditions persisted and the areas our birds were using were remote and
inaccessible to all modes of transport available to us other than an airplane. There is no way to
detect nests from the air; not even a helicopter works. Our attempts to monitor birds using
airboats and an Argo amphibious vehicle were not successful. The areas were too dry for
airboats, but still contained ditches and other water too deep for the Argo to pass. We hope,
going into next years nesting period, surface water is much more abundant in areas other than the
Everglades and this translates into more birds attempting to nest in areas we can adequately
We were able to monitor our urban birds during the nesting period. Our sample size was
small, but if urban birds are representative of all mottled ducks then only 40% attempted to nest
this year. Conditions were dry going into the nesting period and data exist that suggest nesting
by mottled ducks is delayed and curtailed under similar conditions (Grand 1992, Johnson et al.
2002, Finger et al. 2003, Durham and Afton 2006). Data also exist that suggest mottled ducks will
increase there nesting effort late in a nesting season if surface water conditions improve (Johnson
et al. 2002). The sparse data we have so far support these findings.
FIELD SEASON 2009-10
We will continue to locate radio-marked females regularly until they die or until the
transmitters fail. We will begin trapping and radio-marking new females in rural environments in
August and in urban/suburban areas in October. Our goal is to capture and radio-mark an
additional 100 females in 2009 and again in 2010.
2009 Mottled Duck Telemetry Report - 13
We greatly appreciate the funding support Ducks Unlimited has provided this project.
Without the $60,000 Ducks Unlimited provided we would not have been able to start this study.
We also thank AHRES for their financial support of this work. Much appreciation goes to Dr.
Darryl Heard and his personnel from the University Of Florida Veterinary School. Without their
expertise there is no way we could have performed 47 surgeries in two nights. Many thanks go
to Christy Coghlin (South Florida Water Management District) Jim Rodgers, Jamie Feddersen,
Andrew Fanning, Kevin Rodgers, Chad August, and Matt Carney who assisted with capture,
processing, and release of birds. Lastly, we than Mike Milleson with USDA-Wildlife Services
for loaning us their air-powered net cannon. With it we should be able to catch the urban birds
Durham, S. R. and A. D. Afton. 2006. Breeding Biology of Mottled Ducks on Agricultural
Lands in Southwestern Louisiana. Southeastern Naturalist. 5(2):311–316
Chamberlain, E. B., Jr. 1960. Florida waterfowl populations, habitats, and management.
Florida Fish and Wildlife Conservation Commission, Tech. Bull. 7. 62pp.
Cox, D. R. 1972. Regression models and life-tables (with discussion). J.R. Stat. Soc. Ser. B
Finger, R. S., B. M. Ballard, M. T. Merendino, J. P. Hurst, D. S. Lobpries, and A. M. Fedynich.
2003. Habitat use, movements, and survival of female mottled ducks and ducklings
during brood rearing. Texas Parks and Wildlife Department, Austin, Texas, USA.
Gilmer, D. S., L. M. Cowardin, R. L. Duval, L. M. Mechlin, L. W. Shaiffer, and V. B. Kuechle.
1981. Procedures for use of aircraft in wildlife biotelemetry studies. U.S. Fish and
Wildl. Serv. Resour. Publ. 140. 19pp.
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2009 Mottled Duck Telemetry Report - 16
Figure 2. Proportional use of
habitats by rural caught adult
female mottled ducks in south
Florida September 2008 through
July 2009. PB=Post Breeding,
H=Hunting, LW=Late Winter,
R=Reproductive. Error bars
represent SE of the mean.
2009 Mottled Duck Telemetry Report - 17
Figure 3. Proportional use of
habitats by urban caught adult
female mottled ducks in south
Florida September 2008 through
July 2009. PB=Post Breeding,
H=Hunting, LW=Late Winter,
R=Reproductive. Error bars
represent SE of the mean.
2009 Mottled Duck Telemetry Report - 18
Figure 4. Locations of radio-
marked adult female mottled ducks
during late October and early
2009 Mottled Duck Telemetry Report - 19
Figure 5. Locations of radio-
marked adult female mottled ducks
during early March and late April
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Figure 6. Locations of radio-
marked adult female mottled ducks
during late May and Late June
2009 Mottled Duck Telemetry Report - 21
Figure 7. Mean distance moved
between locations for rural and
urban caught adult female mottled
ducks in south Florida 2008-09.
Error bars represent SE of the