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2016 SOUTHEASTERN NATURALIST 15(1):12–25
History and Nesting Population of Bald Eagles in Louisiana
Nickolas R. Smith1,2,*, Thomas J. Hess Jr.3, and Alan D. Afton4
Abstract - The population of nesting Haliaeetus leucocephalus (Bald Eagle) in Louisiana
reached precariously low numbers in the early 1970s after experiencing marked declines
similar to the rest of the continental population. From 1975 to 2008, aerial surveys of all
known nests have been conducted within the state to monitor the population. We used data
collected over the 34-year nest-monitoring program to quantify the recovery of the nesting
population in Louisiana. Active nests increased exponentially from 7 to 387, exhibiting
a mean annual rate of increase of 11.1 ± 0.3% per year with no indications of slowing.
Accounting for increases in nests over the monitoring period, we found relatively slight
changes in reproduction, with productivity and brood size peaking in 2000 and 1999. By
1990, the nesting population in Louisiana had exceeded each goal of the Southeastern States
Bald Eagle Recovery Plan, and the species was removed from the federal list of endangered
and threatened wildlife in 2007. However, the continued stability and growth of the nesting
population may depend on the ability of Bald Eagles to cope with increasing levels of human
activity, as well as the protection and availability of current and future nesting habitats.
Introduction
Haliaeetus leucocephalus L. (Bald Eagle) experienced a marked population
decline throughout the continental United States in the mid-1900s, reaching an
estimated low of 417 pairs in 1963 (Sprunt and Ligas 1964). The continental population
began to increase after the ban on DDT in 1972 and through federal listing
of the Bald Eagle as an endangered and threatened species in 1978 (Buehler 2000,
USFWS 1978). By 2007, the species was removed from the federal list of endangered
and threatened wildlife (USFWS 2007); however, it continues to be protected
under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act,
and remains a species of conservation concern in Louisiana (Lester et al. 2005).
In the early 1900s, Bald Eagles were described as being common in Louisiana
(Bailey 1919) and documented to be nesting in various parts of the state but mainly
near the coast (Beyer 1900, Beyer et al. 1908). The population subsequently declined,
with reports of only “six or seven active nests” in 1972 (Ray Aycock in
Lowery 1974). Similar to the continental population, the decline in Louisiana was
believed to be linked to DDT, habitat destruction, and human persecution (Murphy
1989, USFWS 2007).
1School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA
70803. 2Current Address - Ducks Unlimited Inc., One Waterfowl Way, Memphis TN 38120.
3Louisiana Department of Wildlife and Fisheries, Rockefeller Refuge, 5476 Grand Chenier
Hwy, Grand Chenier, LA 70743 (deceased). 4US Geological Survey, Louisiana Cooperative
Fish and Wildlife Research Unit, Louisiana State University, Baton Rouge, LA 70803. *Corresponding
author - nrsmith@ducks.org.
Manuscript Editor: Frank Moore
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2016 Vol. 15, No. 1
The continental decline prompted the listing of the Bald Eagle as an endangered
species throughout its southern range, and subsequent efforts were focused at increasing
the breeding population (USFWS 1978). In 1984, a collective recovery
plan (Murphy 1989) was compiled for the southeastern region, which included Louisiana.
The goals of the recovery plan were to achieve a collective 3-year average
of >0.9 young per active nest, >1.5 young per successful nest, and >50% of nests
successful in raising at least 1 young, as well as to establish a monitoring protocol
to measure population vigor and determine if adequate habitat exists.
Aerial nest-monitoring has been used in Louisiana since 1975 to document
population change of Bald Eagles and evaluate management effectiveness (Payne
1975). Our objectives were to document the recovery of Louisiana’s nesting population
of Bald Eagles, using data collected during the nest-monitoring program,
which was employed from 1975 to 2008. Finally, we assessed the population increase
in Louisiana with regard to the overall recovery of the Bald Eagle in the
southeastern region.
Methods
Aerial survey data were collected annually for known Bald Eagle nests in
Louisiana from 1975 to 2008. In Louisiana, nesting occurs in the winter, with
egg laying typically occurring from late September to early February (Louisiana
Department of Wildlife and Fisheries 2005). Herein we designate year by reference
to the springtime portion of the nesting season (e.g., 1974–1975 winter
nesting season = 1975). Reports of nesting activity and nests were provided by
private individuals, state and federal personnel, and the media. Additionally,
other nests were found during nest-monitoring activities and incorporated into
subsequent surveys.
From 1975 to 1985, nest surveys were conducted by the US Fish and Wildlife
Service (USFWS); surveys were continued from 1985–2008 by the Louisiana Department
of Wildlife and Fisheries (LDWF) using the same protocol. Attempts were
made to survey known nests at least twice annually, using a Bell Jet Ranger Model
206B helicopter or a fixed-wing aircraft, such as a Cessna 210 or Cessna 185 float
plane. Aerial-survey techniques used were similar to methodologies reported by
Grier et al. (1981) for fixed-wing aircraft and Watson (1993) for helicopters. Coordinates
(latitude and longitude) of nests sites were recorded using Loran C navigation
equipment until 1992, after which global positioning system (GPS) equipment
was used.
Using the standard 2-flight method (Fraser et al. 1983), the first survey flight
was conducted annually during the egg-laying and incubation periods (October–
January) to determine activity of known nests and locate new nests. Nests were
classified as active by the presence of at least one of the following: (1) one or
more adults in or near a nest with signs of nest refurbishment (i.e., presence of
fresh nesting material); (2) an adult sitting low in the nest presumably incubating;
or (3) the presence of eggs or young. Within the same nesting season, active nests
were revisited during a second flight survey, conducted during January–May,
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2016 Vol. 15, No. 1
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to assess annual nest success, productivity, and mean brood size (henceforth,
collectively referred to as production). Nests were recorded as successful if a
minimum of 1 young, 8 weeks of age or greater, was observed. Annual nesting
success was defined as the proportion of successful nests per active nests with
known outcomes. Productivity was the mean number of young produced per active
nests with known outcomes. Mean brood size was the mean number of young
produced per successful nest.
From 2004 to 2008, complete sampling of all nests for production was logistically
impractical because the nesting population had expanded over a large
geographic area. Therefore during this period, all nests were sampled during the
first flight survey, as done in previous years, but prior to a second flight survey, a
one-sample equivalence test was conducted to determine the sample size necessary
to provide a 95% confidence interval at 95% power (Castelloe 2000). As many active
nests as logistically feasible were then revisited during the second flight survey
while ensuring a minimum subsample was achieved. Nests in which complete
production data were obtained were used to estimate, with 95% confidence, the
number of young produced from all active nests. Prior to 2004, the percentage of
known active nests in which production was not determined within the same nesting
season was considered minimal (< 3%; Louisiana Department of Wildlife and
Fisheries 2005).
For each year from 2004 to 2008, we used PROC MEANS (SAS Institute Inc.
2011) to estimate, with 95% confidence, the mean number of young produced per
active nests with known outcomes. We then multiplied means by the total number
of active nests within that nesting season in order to estimate the total young produced
annually from 2004–2008.
We used general linear mixed models (PROC GLIMMIX; SAS Institute
Inc. 2011) to examine the annual rate of change in (1) numbers of active nests,
(2) numbers of successful nests, (3) numbers of young produced, (4) nest success,
(5) productivity, and (6) brood size. Sample sizes of nests were small when surveys
were initiated and increased throughout the monitoring period; thus, we weighted
models for active nests, successful nests, and number of young produced by their
total for each year, nest success and productivity by the number of active nests, and
brood size by the number of successful nests. We used inclusion of intercept-only
(e.g., null model), temporal linear, and temporal quadratic curvilinear models to
test whether rates had changed over the monitoring period and if so, whether that
change was consistent or variable. We evaluated candidate canonical links and distributions
for each type of response variable (e.g., gamma, Gaussian, Poisson for
count data, and binomial for 0/1 data). Selection of a distribution and model was
based on Akaike’s information criteria, corrected for sample size (AICc), where
distributions and models that best supported the data had the lowest AICc (Burnham
and Anderson 2002). We evaluated goodness-of-fit of a model by comparing model
ΔAICc to that of the intercept-only model. This procedure was followed because of
the lack of application of traditional goodness-of-fit methods like R2, which are not
applicable due to the use of pseudo-likelihoods in calculating generalized mixed
models (Bolker et al. 2009, Liu et al. 2008).
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2016 Vol. 15, No. 1
Results
From 1975 to 2008, the number of known active nests increased exponentially
from 7 to 387 (Fig. 1; Tables 1, 2), exhibiting a mean annual rate of increase of 11.1
± 0.3% per year. As numbers of known active nests increased, locations of nests
expanded from 3 parishes (Terrebonne, Jefferson, and St. Charles) to 38 parishes
throughout Louisiana; however, the majority of nests still occurs in the region surrounding
the 3 original parishes (Fig. 2). Numbers of successful nests and total
Figure 1. Numbers of known active nests, successful nests and total young produced by
Louisiana Bald Eagles from 1975 to 2008 with fitted exponential models weighted by
sample size (active nests = e(0.111*Year - 217.41), successful nests = e(0.098*Year - 190.85), and total young
produced = e(0.114*Year - 222.10) ).
Figure 2. Numbers of known active nests by parish in Louisiana in 1975 and 2008.
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young produced increased exponentially (Table 2) at relatively similar rates as for
active nests, respectively (9.8 ± 0.5% and 11.4 ± 0.3%; Fig. 1). Quadratic models,
which suggest a change in the rate of increase over the monitoring period, were
the next best-fitting models for active nests, successful nests, and total young
produced, having 26.1, 41.7, and 24.0% probability, respectively, of being the bestfitting
model among the models considered (Table 2).
Table 1. Summary of Bald Eagle nesting in Louisiana from 1975 to 2008.
Total
Active Successful young Mean
Year nests nests producedA Nest success Productivity brood size
1975 7 5 6 0.71 0.86 1.20
1976 10 6 8 0.60 0.80 1.33
1977 9 7 10 0.78 1.11 1.43
1978 12 7 10 0.58 0.83 1.43
1979 14 11 12 0.79 0.86 1.09
1980 14 12 17 0.86 1.21 1.42
1981 17 11 18 0.65 1.06 1.64
1982 13 12 17 0.92 1.31 1.42
1983 17 15 21 0.94 1.31 1.40
1984 16 12 18 0.75 1.13 1.50
1985 18 14 22 0.78 1.22 1.57
1986 28 22 37 0.79 1.32 1.68
1987 33 29 49 0.88 1.48 1.69
1988 28 23 39 0.82 1.39 1.70
1989 31 20 36 0.67 1.20 1.80
1990 42 35 55 0.83 1.31 1.57
1991 40 35 54 0.88 1.35 1.54
1992 53 50 88 0.94 1.66 1.76
1993 79 66 96 0.84 1.22 1.45
1994 90 71 131 0.79 1.46 1.85
1995 104 88 156 0.85 1.51 1.77
1996 102 89 155 0.88 1.53 1.74
1997 123 102 166 0.83 1.35 1.63
1998 137 105 158 0.78 1.17 1.50
1999 145 125 197 0.89 1.40 1.58
2000 152 129 213 0.85 1.41 1.65
2001 171 126 208 0.86 1.41 1.65
2002 178 148 238 0.88 1.41 1.61
2003 227 177 297 0.80 1.34 1.68
2004 235 165 314 ± 26 0.81 1.34 1.65
2005 255 149 355 ± 28 0.86 1.39 1.62
2006 283 167 435 ± 28 0.91 1.54 1.69
2007 336 265 465 ± 28 0.86 1.38 1.60
2008 387 266 530 ± 33 0.84 1.37 1.62
AFrom 2004 to 2008, production could not be determined for 20.9% of active nests (n = 1946); thus, a
subsample of nests were used to estimate, with 95% confidence, total young produced. Prior to 2004,
the number of active nests in which production could not be determined was minimal (2.6%, n =
1901); therefore, total young produced was considered an actual count.
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2016 Vol. 15, No. 1
Nest success increased slowly over the monitoring period (1.8 ± 0.8%;
Fig. 3). Model selection using AICc showed that nest success was best described
using a linear model with the next best-fitting model being the quadratic model,
having 38.2% probability of being the best-fitting model among the models considered
(Table 2).
Productivity and brood size were best described using quadratic models, accounting
for 92.8% and 79.7% of their Akaike model weights (Table 2). Modeled
productivity increased from 0.96 until peaking in 2000 at 1.42 (Fig. 3) during which
time the annual growth rate never exceeded 3.1%. Likewise, modeled brood size
increased from 1.33 until peaking at 1.66 in 1999, after which it began to slowly
decrease (Fig. 3). During the first two-thirds of the monitoring period annual production
varied widely, becoming relatively more stable around 1999.
Table 2. Comparison of intercept only, linear (Year), and quadratic curvilinear (Year2) generalized
linear mixed models for active nests, successful nests, total young produced, nest success, productivity,
and brood size of Louisiana Bald Eagles from 1975–2008, including number of parameters (K),
Akaike’s Information Criterion adjusted for small sample size (AICc), difference between the AICc of
the given model and the model with the lowest AICc (ΔAICc), and Akaike’s model weight (wi). Model
distribution and canonical link function is given for each model.
Model – distribution, canonical link function K AICc
ΔAICc
wi
Active-nest models – Poisson, log
Year 3 72.78 0.00 0.739
Year2 4 74.86 2.08 0.261
Intercept only 2 646.64 573.86 0.000
Successful-nest models – Poisson, log
Year 3 95.36 0.00 0.583
Year2 4 96.03 0.67 0.417
Intercept only 2 482.19 386.83 0.000
Total-young-produced models – Poisson,l
Year 3 81.96 0.00 0.760
Year2 4 84.26 2.30 0.240
Intercept only 2 876.06 794.10 0.000
Nest-success models – binomial, logit
Year 3 179.49 0.00 0.564
Year2 4 180.27 0.78 0.382
Intercept only 2 184.19 4.70 0.054
Productivity models – gamma, log
Year2 4 -35.61 0.00 0.928
Year 3 -30.03 5.58 0.057
Intercept only 2 -27.38 8.23 0.015
Brood-size models – gamma, log
Year2 4 -45.97 0.00 0.797
Intercept only 2 -42.28 3.69 0.126
Year 3 -41.30 4.67 0.077
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Discussion
Observed increases in nest success, productivity, and brood size in Louisiana
were not as large as those reported in other studies (Grier 1982, Watts et al. 2008),
wherein previous authors suggested that early increases in production resulted
from reductions in human persecution and/or use of contaminants. These studies,
however, did not control for increasing sample sizes, which may have resulted in
larger changes in production estimates over time. Our findings of slight changes
in production suggests that effects of reduced human persecution and contaminants
may be less than previously assumed, or that nesting Bald Eagles in Louisiana may
have been less affected by these factors. Production rates such as nest success,
productivity, and brood size remained relatively constant in Texas from 1971 to
2005 (Saalfeld et al. 2009), despite rates of change for total number of active and
successful nests and young produced being similar to those in Louisiana. Saalfeld
Figure 3. Nest success, productivity, and brood size of Louisiana Bald Eagles from 1975 to
2008 with best-fitted models weighted by number of active or successful nests (solid lines)
and 95% confidence intervals (dashed lines).
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et al. (2009) speculated that the lack of change in Texas could have been due to the
population being less effected by DDT than other regions or having recovered from
its effects prior to 1971.
Beyond contaminants and human persecution, other factors also likely influenced
the relatively slow increase in production within Louisiana. Even if contaminants
and human persecution affected the population early in the monitoring period, the
increase in the population after the release from those negative effects were likely
offset by other factors, such as expansion into new and possibly less than optimal
nesting areas (Baldwin et al. 2012), changes in age structure and conspecific competition
(Elliott et al. 2011), and even regular cyclic fluctuations (Mougeot et al.
2013). All of these factors together likely influenced production over the entire
monitoring period, but further examination is required to better understand their
individual effects.
Less clear are the factors that potentially influenced the observed annual variation
in production in Louisiana. Hurricanes destroyed a large proportion of nests in
some winters but showed no substantial effect on production as affected nest sites
often were rebuilt (Hess et al. 1994, Ortego et al. 2009). Other factors such as inclement
winter weather and low prey availability may affect annual variation
(Gende et al. 1997, Hansen 1987, Steidl et al. 1997), but these factors have not been
investigated for Louisiana eagles. The small number of nests, especially in the earlier
years, may have exacerbated annual fluctuations in production. During the
monitoring period when there were fewer nests, averages would have been more
susceptible to local factors affecting individuals and their nests, but as the population
increased, averages would have better reflected landscape-l evel effects.
The number of nesting Bald Eagles in Louisiana increased exponentially from
precariously low numbers in 1975 to a minimum of 387 nesting pairs by 2008.
Mean annual rates of increase for total active nests, successful nests, and young
produced (11.1%, 9.8%, and 11.4%, respectively) in Louisiana are indicative of a
healthy and expanding population (Buehler et al. 1991a). These increases are reflective
of the general recovery of nesting Bald Eagles across much of the United
States, as exhibited by other studies in different states and regions (Driscoll et al.
1999, Jenkins and Sherrod 2005, Nesbitt et al. 1990, Saalfeld et al. 2009, USFWS
2007, Watson et al. 2002, Watts et al. 2008).
Similar to the many other Bald Eagle and raptor studies that use infrequent
aerial surveys, there are inherent biases. For example, some of the increase in active
nests observed over the progression of the monitoring period may be a result
of increased observer expertise and discovery of existing but previously undocumented
nests, as noted for other aerial nest surveys (Nesbitt et al. 1998, Saalfeld et
al. 2009). In the same way, survey effort increased and expanded geographically
as the number of nests increased and expanded. Nevertheless, we assumed that the
number of nests not found each year was minimal and that by weighting our estimates
by sample size, these biases would not affect our overall conclusions.
Nest activity also may have been underestimated due to nesting not being initiated
or nests being abandoned prior to a survey flight (Wilson et al. 2014). Likewise,
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production of fledglings may have been overestimated (Nesbitt et al. 1998) because
young in some nests, which were recorded as successful prior to actual fledging,
may not have survived to depart from the nest. Furthermore, nests were excluded
from production analyses if they had unknown outcomes, such as nests that were
never surveyed when young were 8 weeks or older, or nests in which young would
have been 8 weeks of age or older but no young were present regardless of whether
they did not survive or they actually fledged. We believe that such production biases
were minimal and our estimates are consistent among years, as argued by others
(Nesbitt et al. 1998). Therefore, our survey results should represent a minimum estimate
of nesting activity and are expected to reflect the general trend in production
for the population.
The Southeastern States Bald Eagle Recovery Plan (Murphy 1989) outlined
goals for the southeastern region, which included Florida, Georgia, South Carolina,
North Carolina, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Texas, and
Louisiana. The plan considered that recovery was achieved when, along with documentation
of population vigor and adequate habitat, a collective 3-year average
of >0.9 young per active nest, >1.5 young per successful nest, and >50% of nests
successful in raising at least one young was reached. The Louisiana population already
exceeded goals for nest success and young produced per active nest when the
recovery plan was first drafted in 1984; and the 3-year average for young produced
per successful nest was >1.5 by 1986.
The recovery plan also had an objective of 600 active nests distributed across
at least 75% of their historical range, which represented approximately 40 nests
in Louisiana. From 1992 to 1994, efforts were made to expand the Louisiana
population in new areas using an eagle hacking program, as recommended in the
Southeastern States Bald Eagle Recovery Plan (Murphy 1989); this was considered
to be a successful technique in other states (see Jenkins and Sherrod 2005, Nesbitt
et al. 1998). During these 3 nesting seasons, 33 eaglets were transported from
nests in southern Louisiana to a hacking tower at Lake Ophelia National Wildlife
Refuge in central Louisiana. A total of 32 young were successfully fledged from
the hacking tower. A nest was found on the refuge in 1995, but unfortunately it was
not determined whether any of the hacked eagles ever established nesting territories
in the area or if the rate of nesting population increase was greater in this area
compared with surrounding areas. However, prior to the hacking program there
were already >40 known active nests in Louisiana. Thus, the nesting population in
Louisiana has exceeded all recovery criteria every year since 1990 (Table 1), and
the Bald Eagle was removed from the list of threatened and endangered species in
2007 (USFWS 2007).
After the delisting, LDWF ceased annual statewide aerial Bald Eagle surveys;
however, the Endangered Species Act mandates continued monitoring after the
delisting of any species. Accordingly, the USFWS developed a post-delisting
management plan for the Bald Eagle population with a statistical goal of an 80%
probability of detecting a 25% or greater change in the number of occupied nests
when surveyed every 5 years (starting in 2009) over a 20-year period (USFWS
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2016 Vol. 15, No. 1
2009). The plan criteria for defining occupied nests are the same as those used
to define active nests in the Louisiana survey. The plan design uses a dual-frame
estimate with a list frame (list of known nests) and an area frame (set of survey
plots) to estimate the continental population.
Watts and Duerr (2010) expressed concerns about the adequacy of the dualframe
approach if the list frame is not properly maintained. Decreased priority in
nest monitoring by states would cause deterioration in the list frame, which could
degrade the viability of the dual-frame approach, specifically in the latter stages of
this monitoring plan. However, continued maintenance of the list frame is costly,
whereas the dual-frame approach was developed with consideration for cost and
logistics. Sauer et al. (2011) suggest that the dual-frame approach is still more
effective and logistically feasible than an area-only sample and also encourages
maintenance of the nest list.
Accordingly, wildlife managers in Louisiana and elsewhere may want to
consider updating nest-list frames through periodic statewide aerial surveys during
post-delisting monitoring. An alternative option would be to incorporate a citizenbased
nest-reporting system to enhance the list frame between post-delisting
monitoring surveys. This approach would allow for the addition of new nests to
the nest list and provide an update on the status of existing nests. Several states
(e.g., Colorado, Iowa, Texas, New Jersey, Pennsylvania) use citizen-based reporting
systems of various types, consisting of forms, online reporting, and notifying
a local conservation officer (Gross and Brauning 2011, Smith and Clark 2012). A
citizen-based nest-reporting system may be more cost effective than a statewide
aerial survey but would require verification for each site and quality control to
ensure that a nest is not recorded more than once. Likewise, there are many biases
associated with citizen-based reporting (Dickinson et al. 2010); however, such an
effort to maintain nest lists would be in line with the suggestions of a state-based
effort for continued updating and management of the nest list as presented in the
post-delisting monitoring plan (USFWS 2009) and Sauer et al. (2011).
The Bald Eagle is listed as a species of conservation concern (shows evidence of
or the potential for population decline) in Louisiana (Lester et al. 2005); however,
this status may require periodic re-evaluation as the population grows. According to
the Louisiana Comprehensive Wildlife Conservation Strategy (Lester et al. 2005),
if the species were to be considered secure or apparently secure, referring to ≥100
nesting territories (M. Seymour, Louisiana Department of Wildlife and Fisheries,
Baton Rouge, LA, pers. comm.), it may no longer warrant conservation concern. A
change in the state status may not endanger or inhibit the protection of Bald Eagles,
their young, or their nests because these would still be afforded coverage under the
Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act.
Long-term monitoring has documented the recovery of the Bald Eagle, and as
of 2008, the increase of the nesting population has not slowed in Louisiana. However,
the peaking of productivity and brood size in 2000 and 1999, respectively,
along with the relatively high Akaike weights for many of the second best-fitting
quadratic models suggests the increase in the nesting population may be slowing.
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2016 Vol. 15, No. 1
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Future research examining regional population trends may reveal that the most
populated region in southeastern Louisiana may be approaching or have reached
local carrying capacity, which may favor dispersal and promote nesting in other
regions of the state.
Habitat loss and human development may be the most important limiting factors
in the expansion of the Bald Eagle in Louisiana. As eagle numbers grew, so did
Louisiana’s human population, which increased by about 25% from 1970 to 2010
(US Census Bureau 2010). In the past, human activity has been a strong predictor
of Bald Eagle nest-site selection (Andrew and Mosher 1982, Buehler et al. 1991b,
Saalfeld and Conway 2010). Eagles may select areas away from human activity to
nest, but as populations expand they could alter their preferences and move into
populated areas (Guinn 2013). In Florida and Chesapeake Bay, there has been
no apparent effect on productivity for birds nesting in human-dominated settings
(Millsap et al. 2004, Watts 2006). Thus, the continued stability and growth of the
nesting population may depend on the ability of Bald Eagle’s to cope with human
activity and the protection of current and future nesting habitats.
Acknowledgments
We dedicate this manuscript to the memory of Thomas Hess Jr., our co-author who devoted
much of his career to the Bald Eagles of Louisiana. Financial support for this study
and its publication were provided by the Louisiana Department of Wildlife and Fisheries and
the US Fish and Wildlife Service, Division of Federal Aid, through Louisiana State Wildlife
Grant T-98, the Rockefeller Wildlife Refuge Trust, the US Geological Survey-Louisiana Cooperative
Fish and Wildlife Research Unit, and the School of Renewable Natural Resources
at Louisiana State University. We acknowledge the work of W. Dubuc, R. Aycock, G. Melancon,
J. Linscombe, and all the individuals from US Fish and Wildlife Service and Louisiana
Department of Wildlife and Fisheries who assisted with Louisiana’s nest-monitoring program
since 1975. We also thank the landowners who contributed information on nesting eagles. We
appreciate W. Selman, D. Blouin, L. Wang, and 3 anonymous reviewers for providing critical
comments on this manuscript. Any use of trade, firm, or product names is for descriptive purposes
only and does not imply endorsement by the US Government.
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