audubon coastal bird survey€¦ · protocol and description ... i calculate the standard error,...
TRANSCRIPT
Audubon Coastal Bird Survey
First Annual Report, July 2011
Photos: Wilson’s Plover (top) and Least Tern chick (bottom), Erik I. Johnson
Erik I. Johnson
Conservation Biologist, Gulf of Mexico and Mississippi Flyway
National Audubon Society
6160 Perkins Rd., suite 135
Baton Rouge, LA 70808 [email protected]
Table of Contents
Synopsis ........................................................................................................................................................ 2
Background ................................................................................................................................................... 3
Protocol and Description .............................................................................................................................. 4
Summary of Effort......................................................................................................................................... 5
Overview of Analyses.................................................................................................................................... 5
Beach‐nesting Birds ...................................................................................................................................... 7
Colonially Nesting Wading Birds ................................................................................................................... 9
Migratory Shorebirds .................................................................................................................................. 11
Non‐breeding Semiaquatic Birds ................................................................................................................ 13
Moving Forward with ACBS ........................................................................................................................ 13
Acknowledgments....................................................................................................................................... 14
Literature Cited ........................................................................................................................................... 15
Appendix A. Species list by ecological guild and the number and proportion of each species reported. . 16
Synopsis
In response to the BP oil spill in April 2010, the Audubon Coastal Bird Survey (ACBS) was developed and
launched by Mark LaSalle and the staff of the Pascagoula River Audubon Center as a partner program to
the Oiled Bird Monitoring Program established in Louisiana by Jared Wolfe and Erik Johnson at Louisiana
State University and Baton Rouge Audubon Society.
During the first year of the ACBS, dozens of volunteers surveyed 24 sites in Mississippi (MS) and
Alabama (AL) and counted over 65,000 birds representing 160 species. The ACBS survey effort will not
only contribute to an independent analysis on the effects of the oil spill on coastal waterbirds, but also
provide a seasonal and geographic examination of coastal waterbird densities. This report will focus on
the latter because oiled bird data are still being analyzed.
In this report, I analyze bird data by grouping birds in ecological “guilds” to avoid problems associated
with low counts of many individual species, but I also identify patterns for species with sufficient data
and those of high conservation concern. I report on four important coastal waterbird guilds: 1) breeding
shorebirds (e.g. many terns and some plovers), 2) breeding wading birds (e.g. herons and Brown
Pelicans), 3) migratory shorebirds (e.g. many sandpipers and some plovers), and 4) non‐breeding
semiaquatic birds (e.g. gulls and American White Pelicans). For each guild, I present a year‐round
assessment of relative density (number of birds per kilometer, noted as # birds/km). I also quantify the
amount of five types of land use (developed, forested [including wetland and upland forest types], open
lands, emergent herbaceous wetland, and sandy beach) within 1000 meters (m) of each transect and
associated these with bird densities.
During the summer of 2010, many breeding shorebirds and wading birds were present in low numbers
along beachfronts, but numbers peaked in August and September as breeding colonies disassembled
and adults and juveniles dispersed across the coast. For Brown Pelicans in particular, post‐breeding
dispersal densities were highest along beaches with the least amount of human development,
illustrating the need for “wild beaches.” Beaches used by nesting and staging (post‐breeding and pre‐
migratory) Least Terns seemed to have been important sites for Laughing Gulls and other colonially
nesting terns, suggesting that these sites have highly productive foraging habitat, but it is not yet clear,
based on land use categories, why some sites were more productive than others.
Some migratory shorebirds, like Sanderlings, had densities positively correlated with the amount of
available sandy beach, whereas other shorebirds, like Dunlin, were most frequently found on beaches
near large tracts of wetlands. Sandy beachfronts often provide valuable resting places for many
shorebirds (like Dunlin) that forage in wetlands that flood during high tide, and these beachfronts may
be particularly important during migration.
The volunteer response and support of this program has been inspiring, and Audubon thanks all who
have participated! Although much was learned about coastal waterbird use of beachfronts in MS and
AL, many questions remain. As more data are collected on individual species, we will better understand
some of these patterns. ACBS protocols will be modified starting in August 2011 to better answer some
of these questions.
2
Background
On 20 April 2011, the Deepwater Horizon oil rig exploded, beginning the largest accidental marine oil
spill in human history. Sadly, 11 crew members lost their lives during the explosion and dozens more
were injured and traumatized from the explosion. The floor of the Gulf of Mexico, 5000 feet below,
started spewing crude oil, which began drifting towards the northern Gulf Coast, impacting wildlife and
their coastal habitat in four U.S. states (Fig. 1).
Figure 1. Extent and duration of crude oil spilled by the Deepwater Horizon‐Macondo Well blowout as
of 18 October 2010 (1).
To understand the magnitude and scope of the oil spill on bird communities, the Pascagoula River
Audubon Center and the National Audubon Society immediately began mobilizing dozens of skilled
volunteers to survey coastal habitats and collect data on bird abundance and oiling frequency along MS
and AL coasts. Despite logistical issues, including beach closures and safety and health concerns,
Audubon volunteers rose to the challenge and provided one of the few independent (non‐National
Resource Damage Assesment or BP) datasets to assess the effects of the oil spill on wildlife populations.
This report summarizes surveys conducted in MS and AL, collectively known as the Audubon Coastal Bird
Survey (ACBS), and focuses on the density and distribution of birds across this coastal landscape. Survey
efforts similar to the ACBS were conducted in Florida (Choctawhatchee Audubon Society) and in
Louisiana (Louisiana State University and Baton Rouge Audubon Society); these surveys will be used for
broader, coast‐wide analyses in the future, which will include an analysis of oiled bird data.
3
Protocol and Description
The ACBS protocol was modified from the Oiled Bird Monitoring Program developed in Louisiana by
Jared Wolfe and Erik Johnson at Louisiana State University and the Baton Rouge Audubon Society. Mark
LaSalle and the Pascagoula River Audubon Center established fixed survey transects as ACBS sites in MS
and AL, with most routes covering approximately 1.6 km (1 mile) of beachfront, although slightly longer
or shorter transects were covered in some locations when necessary. All birds detected were identified
to species and their numbers were counted; data were submitted to Cornell’s eBird website
(www.ebird.org), where they are publicly available for analysis.
The survey effort provides relative density (# birds/km, hereafter referred to as “density”) for each
species, which can be compared across sites and seasons. Surveys did not account for detection
probability, but given the between‐site consistency of surveying open beachfront habitat, detection
probabilities likely vary little among sites (other than observer bias). One should avoid the temptation
to compare densities between species because species‐specific differences in detection probability
prohibit converting “relative” density to true density for each species.
I use several statistical metrics for analyses. I calculate the standard error, which is a measure of
variation around an average standardized for the number of samples that were used to construct the
average. Typically, when standard errors do not overlap between two groups, the averages of each of
these groups can be considered to be different. In addition, I report an R2 statistic, a measure of
correlation between two variables. For example, if bird density decreases with an increasing amount of
development, these two metrics would have a high R2 value. R2 values range from 0 (no correlation
between two variables) to 1 (perfect correlation between two variables). In ecological datasets, there is
usually considerable noise in the data because many factors can influence a variable such as bird
density. These factors might include weather, land use, disease, predation, food availability, and time of
day. An R2 of 0.3 or 0.4 might suggest that variation in one variable successfully explains variation in
another variable, at least in an ecological context. Engineers, in contrast, would be disappointed with
such low R2 values.
Figure 2. Locations of 24 Audubon Coastal Bird Survey routes in MS and AL.
4
Summary of Effort
Between May 2010 and June 2011, 247 surveys were conducted at 14 ACBS sites in MS and 10 ACBS
sites in AL, averaging about 1.2 party‐hours per survey. Survey locations were typically along accessible
beachfront, ranging from density populated areas, as in Biloxi, to remote sandy dunescapes, as in Bon
Secour National Wildlife Refuge (Fig. 2).
Most sites were first surveyed in June or July 2010 at the peak of the oil spill, with effort remaining
consistently high through November 2010, with 170 surveys tallied to this point. Over the next seven
months survey effort decreased; an additional 77 surveys were completed through June 2011 (Fig. 3).
A total of 160 species were detected over the course of the survey period, with 65,479 individual birds
counted (Appendix A). Over 39% of all birds detected were Laughing Gulls! The second most‐reported
bird was none other than our beloved Brown Pelican (7.3%), followed by Dunlin (5.7%), Forster’s Tern
(5.4%), and Sanderling (5.0%). Teams also located a variety coastal waterbirds of high conservation
concern, including Reddish Egret, Piping Plover, Snowy Plover, Wilson’s Plover, Red Knot, and Least
Tern. The diversity and quantity of coastal waterbirds detected during the survey period are
commendable and this exemplifies the success of the first year of this program.
Figure 3. Number of Audubon Coastal Bird Surveys completed in MS and AL in each month from May
2010 through June 2011.
Overview of Analyses
By averaging across the 24 sites, I examined seasonal changes in waterbird numbers on the MS and AL
coasts. There some fascinating and intriguing trends, and each waterbird group will be discussed below.
In addition, I imported transect locations into ArcGIS 10.0 (ESRI, Redlands, CA) and overlaid them onto
2001 National Land Cover Database maps (2), which illustrates land use categories in 30 x 30 m pixels. I
then created a 1000 m buffer around each ACBS route and quantified the proportion of five land cover
5
categories (developed, forested [including wetland and upland forest types], open lands, emergent
herbaceous wetland (marshes), and sandy beach), excluding open water using Spatial Analyst (Fig. 4).
Figure 4. Locations and 1000 m buffers around 24 Audubon Coastal Bird Survey routes in MS and AL
with land cover use (see legend for color coding).
6
Figure 4 (continued). Two Audubon Coastal Bird Survey routes with 1000 m buffers illustrating the
variation in local land use: Ocean Springs‐Belle Fontaine is dominated by emergent herbaceous wetland
(marsh), whereas Pascagoula Beach is dominated by human development.
Beach‐nesting Birds
Beach‐nesting birds include solitary nesters, like plovers, and colonially nesting birds, like terns and
Laughing Gulls. Wilson’s Plovers were detected only on six surveys from four sites (Mobile Bay‐Bayfront
Beach, Dauphin Island, Pascagoula Beach, and Ocean Springs‐Belle Fontaine), all between 10 June and
13 August, during the post‐breeding dispersal and migration seasons. Snowy Plovers likely nest only at
Bon Secour NWR and Dauphin Island; during the non‐breeding season, they were seen regularly at
Dauphin Island, but just once at each of three beaches with considerable human encroachment –
Pascagoula Beach, Washington St. Pier, and Gulfport.
The most critically threatened beach‐nesting colonial waterbird on the Gulf Coast is the Least Tern (3).
Least Terns are migratory, nesting on sandy beaches along the U.S. Gulf and Atlantic coasts as well as
sandy banks along inland rivers, leaving for wintering grounds in Central and South America in
September, returning in April. Nesting on beaches often puts them in conflict with human beach activity
and populations have declined with increased human beach use.
After Least Terns finish nesting, large groups will “stage” at important roosting and foraging sites.
Averaged across all ACBS sites, it is clear that seasonal Least Tern numbers peaked in August during this
expected staging period (Fig. 5). Many of these are surely local breeders, such as from the Biloxi
beachfront (which is one of the largest Least Tern colonies in the world), but others are probably
southbound birds resting along the Gulf Coast before continuing to their winter grounds in the
Caribbean and northern South America.
7
Interestingly, Laughing Gulls showed a similar spike in numbers in August, before numbers dropped
again in September (Fig. 5). A comparison of Laughing Gull numbers on beaches with few Least Terns (<
10 birds/km) against beaches with high Least Tern counts (>10 birds/km) during the August peak yielded
a striking result: beaches with few Least Terns did not see an August spike in Laughing Gull numbers.
Laughing Gulls appear to preferentially use beaches important for Least Tern staging.
I then compared numbers of other colonially nesting waterbirds (mainly other terns, including Forster’s,
Royal, and Sandwich Terns; see Appendix A) between beaches with many Least Tern and few Least
Terns. Like Laughing Gulls, densities of other colonially nesting waterbirds were higher on beaches with
more Least Terns. It seems that Least Terns are staging on beaches that are productive for a variety of
waterbirds, and identifying these may be particularly important for developing conservation strategies.
Figure 5. Average monthly density (birds/km) of Laughing Gulls (LAGU; red, left axis), other colonially
nesting waterbirds (green, left axis), and Least Terns (blue, right axis) in MS and AL.
Figure 6. Average monthly density (birds/km) of Laughing Gulls (blue) and other colonially nesting
waterbirds (green) by beaches with few Least Terns (<10 birds/km; dashed lines) and many Least Terns
(> 10 birds/km).
8
Why do some beaches attract more Least Terns? Beaches used by Least Terns had slightly less forest
(which provides perches for aerial avian predators) and slightly more nearby wetlands (providing
productive food resources), but differences were minimal with overlapping estimates of error. In short,
it is not yet clear what makes particular beaches attractive to staging or nesting Least Terns. It will be
valuable to see if the same staging beaches are predictably used year after year or if their use is highly
ephemeral and opportunistic.
Figure 7. Land cover percentages (± standard error) between beaches with few (<10 birds/km) and lots
(>10 birds/km) of Least Terns in MS and AL.
The October spikes in Laughing Gull and other colonial nesting waterbird numbers appear to have
occurred on beaches both used by Least Terns and not used by Least Terns (remember Least Terns are
gone during these months), but February spikes in Laughing Gull and other colonial nesting waterbird
numbers increased only on beaches used by Least Terns (Fig. 6). This may reflect waterbirds tracking
highly ephemeral food resources and suggests that high‐quality beaches for Least Terns may be valuable
to other terns and gulls in other seasons. Even so, it is also worth noting that with just one year of data,
it is difficult to assess the degree to which these spikes are a random artifact of limited sampling.
Clearly, there is much more to learn about how colonial waterbirds are using MS and AL beaches.
Colonially Nesting Wading Birds
This group includes birds that congregate in large nesting colonies like egrets, herons, ibis, Anhingas,
Neotropic Cormorants, and Brown Pelicans. In general, these birds are regularly and consistently
detected in small numbers along beachfronts with a post‐breeding pulse in August (Fig. 8). Brown
Pelican numbers were lowest in January–May, but this is likely associated with a return to breeding
areas. It is possible that the remaining birds at ACBS sites away from breeding colonies are subadults
and non‐breeders.
9
Figure 8. Monthly average densities of Brown Pelicans, Reddish Egrets, and other colonially nesting
wading birds at ACBS sites.
August density of Brown Pelicans was better associated with the proportion of developed land cover
within 1000 of transects than other land cover types. Increased human development correlated with
decreased Brown Pelican density (R2 = 0.41; Fig. 9).
Figure 9. Brown Pelican density in August (on a natural logarithmic scale) plotted as a function of
proportion developed land cover within 1000 m of ACBS routes.
10
Migratory Shorebirds
This guild includes a variety of sandpipers and plovers that nest well to our north, many on the Arctic
tundra. The Threatened Piping Plover nests along the northern Atlantic and in the prairie pothole region
of the north‐central U.S. and adjacent Canadian provinces. This inland population is highly imperiled
and color‐band sightings show that they primarily winter along the Gulf Coast (4). Piping Plovers were
seen at only six ACBS sites, including three from Dauphin Island and three in Hancock Co., MS. It is
possible that excessive human activity at many of the ACBS sites is one factor for the limited number of
Piping Plover detections.
Migratory shorebird density peaks during spring and fall migrations (Fig. 10), and it is clear that their use
of beaches diminishes in winter, surely as some birds continue farther south. Because information
about shorebird winter densities on tropical beaches and breeding densities in the Arctic is lacking,
surveying shorebirds during migratory periods is crucial for understanding population trends (5,6).
Increasing ACBS survey frequency during fall and spring migration periods will be incredibly valuable for
understanding migratory shorebird flyways in the Gulf of Mexico.
Figure 10. Monthly average densities of Sanderlings, Dunlins, and other migratory shorebirds at ACBS
sites.
By far, the two most frequently observed migratory shorebirds were the Sanderling and Dunlin (Fig. 10),
but they seem to be using different aspects of the landscape (Figs. 11 and 12). For both species, I
averaged densities across the winter period (October to March) at each site.
Sanderling density increased with increasing beach area (R2 = 0.37; Fig. 11), but did not correlate well
with wetland cover (R2 = 0.06) or developed land cover (R2 = 0.03), illustrating their dependence on
sandy shorelines. Across all sites, Sanderling winter density averaged 20 birds/km, or about 3,000 total
birds along MS and AL beaches, not including MS barrier islands, which were not surveyed. This is about
11
1% of estimated U.S. population (5,7). Sanderling populations are not well understood, but they are
believed to be declining, perhaps because of their exclusive usage of coastal beaches, which are also
favored by humans.
Dunlins were observed at fewer sites, but with large variation in average winter (October to March)
density. Beaches with particularly high counts of Dunlins (> 10/km) were surrounded by nearly three
times as much wetland as beaches with fewer Dunlins (< 10/km; Fig. 12). Their reliance on sandy
beaches may be important when nearby productive wetland foraging sites are temporarily under water
during high tides.
Figure 11. Averaged October through March Sanderling density plotted as a function of proportion of
beach cover within 1000 m of ACBS routes.
Figure 12. Land cover percentages (± standard error) between beaches with low (<10 birds/km) and
high (< birds/km) average density of Dunlins in MS and AL in winter (October through March).
12
Non‐breeding Semiaquatic Birds
This guild includes American White Pelicans, wintering gulls including Herring and Ring‐billed Gulls, and
two species that are passage migrants: Franklin’s Gulls and Black Terns. Franklin’s Gulls, a Laughing Gull
look‐a‐like, were seen at only two sites: Ladner Pier and Buccaneer Beach in Hancock Co. MS. It should
be expected to be more widespread during spring and fall migration but can be difficult to identify.
Black Terns are also largely passage migrants, although some subadults summer along the Gulf of
Mexico in very low numbers. They were seen only on Dauphin Island and Orange Beach but should also
be expected at other sites across the Gulf Coast. They too can be difficult to identify in non‐breeding
plumage.
Although most “winter” gulls and American White Pelicans have small over‐summering populations on
the Gulf Coast (usually subadults), they are predominantly seen in winter (Fig. 13). American White
Pelicans are not typically associated with sandy beach fronts and were seen at only three sites: Bay
Front Beach (Mobile Bay), Ocean Springs‐Belle Fontaine, and Point Aux Chenes. These sites are distinct
in having extensive marsh systems nearby. Winter gull density did not appear to correlate with the
proportion of any land cover (all R2 < 0.1).
Figure 13. Monthly average density of all gulls (not including Laughing Gulls or Franklin’s Gulls) and
American White Pelicans at ACBS sites.
Moving Forward with ACBS
ACBS, originally established through the Pascagoula River Audubon Center in response to the BP oil spill,
is already providing valuable population and habitat use data for a variety of coastal waterbirds, many of
which are experiencing population declines (7). Several patterns reported here are not particularly
surprising, like seasonal fluctuations in bird densities, but validate that the data collected over the last
13
year have the potential to reveal changes in populations, if survey efforts continue. An expanded ACBS
program will provide scientists with valuable data for addressing conservation needs of coastal
waterbirds.
For decades, state and federal agencies have been collecting data on colonially nesting waterbird
rookeries during the breeding season, providing a record of breeding bird populations, but we lack a
sophisticated year‐round understanding of waterbird population dynamics (8). ACBS has the potential
to fill this void and provide a year‐round dataset at a regional scale and will be an important tool for
conserving important coastal habitats for these species.
A pressing need for coastal studies includes understanding migratory shorebird use of coastal habitats
and the influence of human pressure on their staging and feeding areas. Frequent coastal waterbird
surveys during key migratory and winter periods will be used to understand how waterbirds use coastal
habitats locally and across the northern Gulf of Mexico and will also be consistent with monitoring
needs developed by regional and national waterbird and shorebird conservation plans (5, 8–11). In
addition, ACBS will be used to compliment International Shorebird Surveys, the primary tool for
understanding migratory shorebird population trends in the Western Hemisphere (12).
Acknowledgments
This report would not have been possible without the hard work of dedicated citizen scientists and the
support of their friends and families. The volunteer support for this program has been inspiring, and
Audubon is grateful for each and every person’s participation. Hard work by dedicated volunteers has
already provided one year of valuable data, and continued participation will strengthen the current
dataset and provide new insights into waterbird ecology across the northern Gulf of Mexico. Many
thanks and congratulations to you for your participation and making this program a success!
Not only have volunteers been collecting usable scientific data, but experienced bird watchers also have
been mentoring a new generation of birders! A great enjoyment of bird watching is that there is always
something to learn. Surely all participants involved have experienced new insights by interacting with
others that share the same passions.
Dr. Mark W. LaSalle and staff at the Pascagoula River Audubon Center, including Mozart Dedeaux, as
well as Audubon’s Mississippi Volunteer Coordinator, Dustin Renaud, and Alabama Volunteer
Coordinator, Kelsey Blum, helped establish and coordinate the ACBS program in Mississippi and
Alabama. Jared Wolfe, a graduate student at Louisiana State University, established the Oiled Bird
Monitoring Program in Louisiana, which provided a framework for ACBS design and data collection.
Chris Wood at Cornell University helped coordinate the eBird data entry and extraction processes.
14
Literature Cited
1. European Space Agency. 2010. Bluefin tuna hit hard by ‘Deepwater Horizon’ disaster. ESA News, 18
Oct. 2010. http://www.esa.int/esaCP/SEM1K4WO1FG_index_0.html#subhead2, Accessed 15
July 2011.
2. Homer, C., C. Huang, L. Yang, B. Wylie, and M. Coan. 2004. Development of a 2001 National Land‐Cover Database for the United States. Photogrammetric Engineering and Remote Sensing 70:829–840.
3. Sidle, J. G. and W. F. Harrison. 1990. Recovery Plan for the Interior Population of the Least Tern
(Sterna antillarum). U.S. Department of the Interior, U.S. Fish and Wildlife Service, Twin Cities, Minnesota.
4. Elliott‐Smith, E., S. M. Haig, and B. M. Powers. 2009. Data from the 2006 International Piping Plover
Census. U.S. Geological Survey, Reston, Virginia. 5. Brown, S., C. Hickey, B. Harrington, and R. Gill. 2001. United States Shorebird Conservation Plan.
Manomet Center for Conservation Sciences, Manomet, Massachusetts. 6. Howe, M. A., P. H. Geissler, and B. A. Harrington. 1989. Population trends of North American
shorebirds based on the International Shorebird Survey. Biological Conservation 49:185–199. 7. Morrison, R. I. G., B. J. McCaffery, R. E. Gill, S. K. Skagen, S. L. Jones, G. W. Page, C. L. Gratto‐Trevor,
and B. A. Andres. 2006. Population estimates of North American shorebirds, 2006. Wader Study Group Bulletin 111:67–85.
8. Hunter, W. C., W. Golder, S. Melvin, and J. Wheeler. 2006. Southeast United States Regional
Waterbird Conservation Plan. U.S. Geological Survey, Patuxent, Maryland.
9. Elliott, L. and K. McKnight. 2000. U.S. Shorebird Conservation Plan: Lower Mississippi/Western Gulf Coast Shorebird Planning Region. Gulf Coastal Prairie Working Group.
10. Hunter, W. C., J. Collazo, B. Noffsinger, B. Winn, D. Allen, B. Harrington, M. Epstein, and J. Saliva.
2002. U.S. Shorebird Conservation Plan: Southeastern Coastal Plains‐Caribbean Region Report. 11. Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson,
N. Edelson, R. Elliot, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, B. Sydeman, J. Trapp, J. Wheeler, and K. Wohl. 2002. Waterbird Conservation for the Americas: The North American Waterbird Conservation Plan. Waterbird Conservation for the Americas, Washington, D.C.
12. Bart, J., S. Brown, B. Harrington, and R. I. G. Morrison. 2007. Survey trends of North American
shorebirds: population declines or shifting distributions? Journal of Avian Biology 38:73–82.
15
Appendix A. Species list by ecological guild and the number and proportion of each species reported.
Guild/species Count % Guild/species Count %
Breeding Shorebird 38085 58.2 Breeding Wading Bird 5890 9.0
Laughing Gull 25736 39.3 Brown Pelican 4775 7.3
Forster's Tern 3512 5.4 Great Blue Heron 374 0.6
Royal Tern 3134 4.8 Snowy Egret 308 0.5
Black Skimmer 1885 2.9 Great Egret 158 0.2
Least Tern 1512 2.3 Little Blue Heron 54 0.1
Willet 893 1.4 Reddish Egret 54 0.1
Sandwich Tern 823 1.3 Yellow‐crowned Night‐Heron 45 0.1
Caspian Tern 258 0.4 White Ibis 35 0.1
Common Tern 92 0.1 Tricolored Heron 27 0.0
Gull‐billed Tern 69 0.1 Cattle Egret 25 0.0
American Oystercatcher 60 0.1 Black‐crowned Night‐Heron 13 0.0
tern sp. 54 0.1 Anhinga 12 0.0
Snowy Plover 48 0.1 egret sp. 6 0.0
Wilson's Plover 9 0.0 Green Heron 4 0.0
Non‐breeding Semiaquatic 3100 4.7 Migratory Shorebird 9669 14.8
Black Tern 1514 2.3 Dunlin 3736 5.7
Ring‐billed Gull 741 1.1 Sanderling 3254 5.0
gull sp. 334 0.5 Short‐billed/Long‐billed Dowitcher 801 1.2
Herring Gull 289 0.4 Semipalmated Plover 527 0.8
American White Pelican 129 0.2 Black‐bellied Plover 311 0.5
Bonaparte's Gull 73 0.1 Ruddy Turnstone 220 0.3
Franklin's Gull 18 0.0 shorebird sp. 202 0.3
Great Black‐backed Gull 2 0.0 Least Sandpiper 135 0.2
Western Sandpiper 125 0.2
Marshbird 162 0.2 Semipalmated Sandpiper 111 0.2
Seaside Sparrow 79 0.1 Piping Plover 54 0.1
Clapper Rail 41 0.1 peep sp. 34 0.1
Mottled Duck 14 0.0 Greater Yellowlegs 31 0.0
Marsh Wren 13 0.0 Barn Swallow 30 0.0
Nelson's Sparrow 5 0.0 Marbled Godwit 26 0.0
Black‐necked Stilt 3 0.0 Lesser Yellowlegs 16 0.0
Sedge Wren 3 0.0 Red Knot 15 0.0
Sora 2 0.0 Spotted Sandpiper 15 0.0
Purple Gallinule 1 0.0 White‐rumped Sandpiper 9 0.0
Virginia Rail 1 0.0 American Avocet 8 0.0
Whimbrel 3 0.0
16
Waterfowl and Allies 1543 2.4 Greater/Lesser Yellowlegs 2 0.0
Double‐crested Cormorant 828 1.3 Stilt Sandpiper 2 0.0
Greater/Lesser Scaup 204 0.3 Pectoral Sandpiper 1 0.0
Blue‐winged Teal 131 0.2 Solitary Sandpiper 1 0.0
Bufflehead 105 0.2
Lesser Scaup 94 0.1 Introduced 876 1.3
Common Loon 56 0.1 Canada Goose 498 0.8
Horned Grebe 37 0.1 Mallard 378 0.6
American Coot 31 0.0
Red‐breasted Merganser 25 0.0 Pelagic 7 0.0
Pied‐billed Grebe 10 0.0 Northern Gannet 6 0.0
Green‐winged Teal 8 0.0 Magnificent Frigatebird 1 0.0
Common Goldeneye 5 0.0
Hooded Merganser 4 0.0 Semiaquatic Raptor 133 0.2
Greater Scaup 3 0.0 Osprey 116 0.2
Gadwall 2 0.0 Bald Eagle 17 0.0
Landbird 6014 9.2 Landbird 6014 9.2
Killdeer 1155 1.8 Brown Thrasher 6 0.0
Purple Martin 823 1.3 Eastern Phoebe 6 0.0
Red‐winged Blackbird 671 1.0 Northern Rough‐winged Swallow 6 0.0
Barn Swallow 517 0.8 Turkey Vulture 6 0.0
Cliff Swallow 483 0.7 Chipping Sparrow 5 0.0
Brown‐headed Cowbird 401 0.6 Common Ground‐Dove 5 0.0
Rock Pigeon 270 0.4 Eastern Kingbird 5 0.0
Mourning Dove 217 0.3 Eastern Towhee 5 0.0
European Starling 200 0.3 White‐winged Dove 5 0.0
Yellow‐rumped Warbler 160 0.2 Yellow‐throated Warbler 5 0.0
Fish Crow 147 0.2 American Kestrel 4 0.0
Common Grackle 129 0.2 Blue‐gray Gnatcatcher 4 0.0
Northern Mockingbird 109 0.2 Common Yellowthroat 4 0.0
Blue Jay 61 0.1 Swallow‐tailed Kite 4 0.0
American Crow 51 0.1 Northern Flicker 3 0.0
Northern Cardinal 49 0.1 Tree Swallow 3 0.0
House Finch 47 0.1 Cooper's Hawk 2 0.0
Boat‐tailed Grackle 38 0.1 Hairy Woodpecker 2 0.0
Eastern Bluebird 38 0.1 House Wren 2 0.0
Loggerhead Shrike 36 0.1 Peregrine Falcon 2 0.0
Red‐bellied Woodpecker 34 0.1 Red‐shouldered Hawk 2 0.0
Carolina Chickadee 33 0.1 Song Sparrow 2 0.0
American Goldfinch 27 0.0 American Pipit 1 0.0
Eurasian Collared‐Dove 27 0.0 Barred Owl 1 0.0
17
18
Ruby‐th. Hummingbird 24 0.0 Bobolink 1 0.0
Tufted Titmouse 20 0.0 crow sp. 1 0.0
Carolina Wren 19 0.0 Downy Woodpecker 1 0.0
House Sparrow 19 0.0 Eastern Meadowlark 1 0.0
Red‐headed Woodpecker 12 0.0 flycatcher sp. 1 0.0
Belted Kingfisher 11 0.0 Gray Catbird 1 0.0
Pine Warbler 11 0.0 Gray Kingbird 1 0.0
Swamp Sparrow 11 0.0 Merlin 1 0.0
Brown‐headed Nuthatch 10 0.0 Pileated Woodpecker 1 0.0
Northern Harrier 9 0.0 Sharp‐shinned Hawk 1 0.0
American Robin 8 0.0 Snow Goose 1 0.0
Chimney Swift 8 0.0 Western Kingbird 1 0.0
Palm Warbler 8 0.0 White‐eyed Vireo 1 0.0
Red‐tailed Hawk 8 0.0 White‐throated Sparrow 1 0.0
Savannah Sparrow 8 0.0 Yellow‐bellied Sapsucker 1 0.0