National Park Service

South Florida/Caribbean I&M Network (SFCN)

Colonial Nesting Birds Monitoring

Great White Heron in Biscayne National Park
Great White Heron in Biscayne National Park.

Resource Briefs

Monitoring Reports

Protocol

For more information contact:

Kevin R. T. Whelan, Ph D.

Robert Muxo

Importance/Issues

Colonial nesting birds such as great egrets, wood storks, white ibis, snowy egrets, roseate spoonbills, brown pelicans, cormorants, and sooty terns, are very important as vital signs of the health of our national parks. The presence of colonial nesting birds, the size and distribution of their nesting colonies and the reproductive success of their nests indicate that the surrounding habitat is able to support these energy intensive activities. These birds must acquire large quantities of high quality food during the nesting season as they select mates, build nests, lay eggs, and rear chicks. Colonies are susceptible to disturbance and predation pressure. Thus, a decrease in nesting effort and nesting success as well as local population declines may indicate that the ecosystem is not functioning properly. Many of these colonial nesting species have already experienced declines and are listed as species of special concern, threatened, or endangered.  Our goal is to track the status and trend by monitoring the number of occupied and non-occupied active nests in a colony.

Monitoring Objectives

What are the status and trends in colony size, distribution, and active nest of specific colonial nesting birds?

Status and Trends

Biscayne National Park

The SFCN is developing a protocol to monitor the active nests of colonial nesting birds in Biscayne National Park (BISC).  Nesting colonies have been found on six islands, Mangrove Key, West Arsenicker Key, Arsenicker Key, Jones Lagoon, Ragged Key 5, and Soldier Key. Double-crested Cormorants are the most abundant bird in BISC with 95% of the nests.

The SFCN completed its fifth year of monitoring colonial nesting birds in Biscayne National Park (BISC). The collected data (through July 2013) has been entered into the Access database and verified for accuracy. The results of monitoring have yielded valuable nesting data (Figures 1, 2 and Table 1) that provide for observation of species-specific nesting patterns and trends. The Colonial Nesting Bird Protocol has been submitted for internal review and editing and should be ready for external review in early fiscal year 2014.

Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Double-crested Cormorant NF 477 403 296 NF 434 641 NF 505 NF 148 126
Great Blue Heron NF 2 2 1 NF 3 0 NF 0 NF 1 9
Great Egret NF 0 0 10 NF 12 0 NF 0 NF 7 0
Great White Heron NF 14 4 5 NF 6 0 NF 6 NF 8 9
Roseate Spoonbill NF 3 0 0 NF 0 0 NF 0 NF 0 1
White Ibis NF 0 0 0 NF 28 18 NF 0 NF 0 0
Total NF 496 409 312 NF 483 659 NF 511 NF 164 145
Table 1.Totals of occupied nests counted by species and month for the calendar year 2012. Double-crested Cormorants account for the majority of nests counted in BISC, from a high of 99% in March to a low of 82% in December. Note: An occupied nest contains an egg, chick or adults in immediate proximity with signs of occupation. The nesting process can take longer than a single month, hence an occupied nest may be counted in multiple months. NF indicates "No Flight" for that month.
Figure 1. The number of Double-crested Cormorant nests per month, as well as the peak nesting periods
Figure 1. The number of Double-crested Cormorant nests per month, as well as the peak nesting periods.
Figure 2. Peak nesting and seasonal trends for five monitored species. Key: Great Blue Heron = GBHE, Great Egret = GREG, Great White Heron = GWHE, Roseate Spoonbill = ROSP, and White Ibis = WHIB
Figure 2. Peak nesting and seasonal trends for five monitored species. Key: Great Blue Heron = GBHE, Great Egret = GREG, Great White Heron = GWHE, Roseate Spoonbill = ROSP, and White Ibis = WHIB.

The species of birds in BISC can be broken down into three functional types based on their feeding behavior: divers, stalk and strike, and tactile. Double-crested Cormorants are divers and are the most abundant bird in BISC averaging more than 90% of the nests counted in 2012 (Table 1). Different nesting seasonality is evident for the various species (Figures 1, 2). Roseate Spoonbills and White Ibis are both tactile feeders, yet each species nests during different seasons (Figure 2). Changes in nesting trends provide indicators of conditions in the park that support nesting behavior. Due to scheduling conflicts and pilot/ airplane availability, no SFCN monitoring flight was performed at BICY in 2013.

Figure 3. An adult Roseate Spoonbill watches over two chicks in a nest at Jones Lagoon in Biscayne National Park
Figure 3. An adult Roseate Spoonbill watches over two chicks in a nest at Jones Lagoon in Biscayne National Park.

in 2014, SFCN will continue monthly helicopter flight monitoring in BISC. The Colonial Bird Monitoring Protocol and SOP for data reporting should be submitted for external review. In order to provide consistency, data for 2010 and part of 2011 will be reviewed to include empty nests as part of active nest counts. In the nesting season of 2014, the SFCN plans to resume the fixed-wing aircraft flight through BICY searching for confirmation of bird colonies. Observations will be reported to BICY resource management and Dr. Peter Frederick. If these monitoring efforts continue to receive funding from CERP- RECOVER, this colonial bird monitoring collaboration should continue in FY14.

Everglades National Park

Status and trends for this vital sign are reported as part of the South Florida Ecosystem Restoration Task Force 2010 System-wide Ecological Indicators for Everglades Restoration (See page 12–17 in this report) and the CERP RECOVER 2009 System Status Report Greater Everglades: Everglades Coastal Wetlands Results and the Greater Everglades: Wading Bird Nesting in Relation to Aquatic Fauna Forage Base (Predator-Prey) Result.

Big Cypress National Preserve

In April of 2012, the SFCN performed a monitoring flight in BICY to assist in the assessment of nesting bird populations inside BICY.  Although wading birds were observed at the remaining watering holes, no nests for these birds were detected.  This information was passed on to Peter Frederick of The University of Florida who monitors nesting birds in BICY.

SFCN is working with the respective monitoring agencies and park staff to see if these other monitoring efforts can be reported through the Vital Signs process. Using input from BUIS, VIIS, and EVER, the SFCN has drafted Standard Operating Procedures (SOP’s) for colonial bird monitoring in their respective parks.

Approach

Biscayne National Park

SFCN is currently developing a monitoring protocol and conducting pilot monitoring of colonial nesting birds in Biscayne National Park (BISC). Bi-annual reconnaissance helicopter flights are conducted park-wide in the spring and fall to determine colony locations. Once colonies’ locations are determined, monthly monitoring commences and involves taking photographs from a helicopter of nesting activities. The photographs are analyzed for active nests and compared sequentially to ensure nests are not double-counted. The information is then recorded to help determine trends in nesting populations of colonial birds in BISC. A boat survey was conducted in April 2011 to compare data collected from a boat to the data collected from a helicopter flight the same month.  Once again the helicopter was shown to provide the best platform for gathering nesting quantities in BISC.  Annual peak nest counts are a primary summary metric being considered for evaluating trends. The species of birds in BISC can be broken down into three functional types based on their feeding behavior: divers, stalk and strike, and tactile. Primary species recorded include Double-crested Cormorants, Great Blue Heron, Great Egret, Great White Heron, Roseate Spoonbill, and White Ibis. Small egrets and darker herons (e.g., little blue heron) are not detectable and often nest deeper within the canopy and are difficult to count accurately so they are not included.  2013 marks the completion of the fifth year of colonial bird monitoring in BISC by the SFCN.

Everglades National Park

Monitoring of wood storks, white ibis, great egrets, etc. consists of Systematic Reconnaissance Flights (SRFs) conducted monthly since 2007 via fixed-wing aircraft during which colonies are located, photographed, and recorded. If large enough, these colonies are added to the traditional historical colony surveys which visit each colony on a monthly basis and record the number of nests and nesting stage by species. Monitoring is conducted by EVER park staff. Roseate Spoonbill nesting is monitored separately by Audobon in Florida Bay.

Big Cypress National Preserve

SFCN conducts an annual reconnaissance monitoring flight to locate large colonies within BICY.  This year’s flight visited historical nesting sites but no nesting colonies were detected.  These observations confirmed previous data collected by Peter Frederick of the University of Florida whom has been monitoring colonial bird populations in BICY for several years.

Dry Tortugas National Park

At Dry Tortugas National Park the Sooty Tern and Brown Noddy nesting populations have been monitored since the 1950’s by Everglades National Park due to the importance of these unique breeding colonies in the U.S.

Virgin Islands National Park

Park staff monitor brown pelican nests at Mary’s Point and Whistling Cay and involve identifying the colony locations, determining the probable nesting periods and sampling at regular intervals during the nesting season. Brown Pelican adults, juveniles, and if possible chick counts are performed. Annual peak nest counts are the primary summary metric reported.

U. S. Fish and Wildlife Service and Virgin Islands Department of Fish and Wildlife are conducting monitoring of Roseate and Least Terns. 

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Last Updated: March 28, 2017 Contact Webmaster