Florida Beach-nesting Bird Report Summary of FWC s Beach-nesting Bird Database from

Transcription

1 Florida Beach-nesting Bird Report Summary of FWC s Beach-nesting Bird Database from Prepared by Chris Burney FWC Shorebird Partnership Coordinator chris.burney@myfwc.com

2 FLORIDA BNB REPORT Florida Beach-nesting Bird Report A look back at the data collected from 2005 to 2008 and a look forward at considerations for the future. INTRODUCTION For those of you regularly submitting data online to the Florida Beach-nesting Bird (BNB) database, you are probably very familiar with the activity on your stretch of beach but not sure how the birds and sites you monitor factor into the bigger picture. In view of this, we have produced the following report which summarizes the data compiled in the BNB database from 2005 to We hope that it will provide you, our contributors, a more statewide perspective. These data would certainly not be available if not for the dedicated work of our partners from federal, state, and local governments to private conservation organizations and individuals. Thank you for your continuing efforts to monitor and protect Florida s beach-nesting birds! Please keep in mind that the BNB database was initially designed as a tool to provide real-time information to coastal managers in order to help guide management decisions (permitting process, determining compatible recreational uses, etc.). Because there are gaps and inconsistencies in coverage and survey effort and methods vary between sites and from year to year, we cannot interpret these data in the same way we would those from a systematic survey. This means that you should use a great deal of caution in interpreting the tables and maps presented in this report. For instance, we definitely can not draw conclusions about population status and trends (e.g. how many Least Terns nest in Florida, and whether or not they are declining) from such assorted data. Despite these limitations, the BNB database does function as a resource for current information about the distribution (i.e. where birds are nesting) and relative abundance (i.e. how many pairs are nesting compared to other sites) of beachnesters and provides valuable information for developing regional and statewide conservation priorities. Furthermore, our network of contributors is steadily growing and expanding, giving us a more comprehensive picture with each successive year. We have accumulated a considerable amount of data Photos- 1. American Oystercatcher (Haematopus palliatus)- juvenile begging adult for food, 2. Laughing Gull (Leucophaeus atricilla)- nest with eggs, 3. Least Tern (Sternula antillarum)- juvenile. Photos taken by Jack Rogers. 1

3 Nests Nest Totals (ground nests only) Figure 1. Annual totals for nests* submitted to the BNB database. in three and a half years (2005 was a partial year). At the close of the 2008 season, over 5400 individual observations had been submitted to the BNB database and from these over 166,000 ground nests were recorded*. Annual totals for ground nests have increased each year (Fig. 1) which is not necessarily a sign that beach-nesting birds are rebounding but a reflection of the increasing number of monitors contributing observations to the BNB database each year. Hopefully, we can continue this trend so we can begin to develop a clearer picture of what is happening with our seabird and shorebird populations. DATA SUMMARIES This report summarizes only ground-nesting data (rooftop data excluded) for the following species: Least Tern Royal Tern Caspian Tern Sandwich Tern Gull-billed Tern Black Skimmer Year Laughing Gull American Oystercatcher Willet Snowy Plover Wilson s Plover Summary Tables Summary tables 1-3 (p. 5-7) provide basic information on nesting activity for beach-nesting shorebirds and seabirds. Table 1 presents count totals for shorebird nests and chicks by species, year, and FWC region (see FWC regional boundaries, p. 8). Table 2 presents colony totals for seabirds by species, year, and *Does not include rooftop nests and large colonies in the Dry Tortugas. FWC region, and includes the number of sites that were also active during the FWC Colonial Seabird Survey. Table 3 presents count totals for seabird nests and chicks by species, year, and FWC region. Shorebirds Relative to seabirds, shorebirds (due to their more secretive and solitary nesting habits) are much more difficult to find and we receive fewer observations as a result. Many of the data for shorebirds (Table 2) were collected during species-specific studies (e.g State-wide Snowy Plover survey). Consequently, the data are clumped in certain years for some species. Apart from these studies, the number of observations for shorebird nests is gradually increasing as the network expands and partners become more familiar with the nesting habits of these species.. Given the imperiled conservation status of our shorebirds, particularly Snowy Plovers, it is important to continue improving the quality and extent of our coverage for these species. Surveys such as the proposed annual Snowy Plover Count can help. This quick survey will provide a good preliminary map for nesting pairs across the state. This project will help facilitate the identification and posting of additional plover nests and ultimately, may improve the situation for this threatened species in Florida. For more information about this count and how to get involved, shorebird@myfwc.com. Seabirds Bright plumages, dive-bombing nest defense, colonial nesting habits, and site fidelity make seabirds easier to find than shorebirds. With the possible exception of our highly opportunistic and somewhat unpredictable least terns, we are confident that the majority of ground colonies in Florida are found and monitored each year. For most of our seabird species we can make reasonable assumptions about the distribution and relative abundance of these colonies from the data. The Colonial Seabird Survey provided important baseline information on colony size and location for much of our current monitoring. Nearly half (54/128) of the ground colonies found during the survey (historical sites) were active at least one year between (Fig. 2). One hundred and one (101) new sites were added to the database from , giving us a total of 155 active ground colonies between those years. In relation to FWC regions (Map 1), ground colonies are not evenly distributed around the state (Fig. 3). The majority occur on the west coast. The Gulf waters are comparatively calmer than the Atlantic Ocean, allowing a more extensive network of barrier islands, estuaries, and coastal lagoons to develop which in turn, support a higher number and diversity of beach- 2

4 FLORIDA BNB REPORT Sites New vs. Historic Sites, New Historic Laughing Gull Black Skimmer Gull-billed Tern Sandwich Tern Caspian Tern Royal Tern Least Tern Total and management much more complicated. On the other hand, showing flexibility and placing their eggs in a lot of baskets reduces the risk associated with catastrophic events. Given our limited resources and these challenges, how do we set conservation priorities? Carefully. The big sites are obviously important, but the remaining small and scattered sites are arguably no less critical to protect since collectively they may represent a significant portion of the population for species that are of great conservation concern. Maps Maps for select species can be found on pages Seabird maps summarize colony size and location data, and shorebird maps provide nest locations only. Additional maps were created with the data on Least Terns. The first map (Map 2) compares coverage between the comprehensive Colonial Seabird Survey to the BNB database from , and the second map (Map 3) illus- Species 180 Sites by Region and Species, Figure 2. Colonial seabird sites from by species comparing the number of new sites to the number of historic sites (recorded active during the FWC Colonial Seabird Survey). nesting seabirds. The impact of development and other humanrelated influences have not been quantified but undoubtedly play a role in distribution as well. The difference in number of sites (Fig. 3) between species (i.e. least terns vs. laughing gulls) is due more to the differences in their nesting strategies than their population sizes. In general, our seabirds fall into two categories- species that nest exclusively in a few, large, multi-species colonies (Royal Tern, Sandwich Tern, Caspian Tern, Laughing Gull) and exhibit strong site fidelity, and those species that are more opportunistic, nesting in colonies of varying size that are established anywhere suitable conditions present themselves. These pioneering species (Least Tern and Black Skimmer) are better at quickly taking advantage of newly formed habitats wherever they may occur and, thus, are less predictable. From a management perspective, there are pros and cons to both nesting strategies. Seabirds which consistently nest in large numbers in a few places should be easy to monitor and manage. Approximately 90% of the seabird nests (ground colonies only) are concentrated in less than 10% of the sites! However, nesting in a limited number of sites makes these species highly vulnerable should management fail or sites disappear (e.g. Passage Key). Conversely, the opportunistic species nest too randomly and in many places, making effective monitoring Sites Total Least Tern Royal Tern Caspian Tern Species Sandwich Tern Gull-billed Tern Black Skimmer Laughing Gull Figure 3. Number of seabird ground colonies from by species showing the distribution by region. SW S NW NE NC 3

5 7902 * Nests Observed by Species, Least Tern Royal Tern Caspian Tern Sandwich Tern Gull-billed Tern* Black Skimmer Laughing Gull NAME CHANGES Recently, the American Ornithological Union (AOU) made significant changes in the scientific nomenclature of several species of beach-nesting shorebird and seabird. LARIDAE Larinae Leucophaeus atricilla Laughing Gull- formerly in the genus Larus Sterninae Onychoprion fuscatus Sooty Tern- formerly in the genus Sterna Onychoprion anaethetus Bridled Tern- formerly in the genus Sterna Sternula antillarum Least Tern- formerly in the genus Sterna Gelochelidon nilotica Gull-billed Tern- formerly in the genus Sterna Hydroprogne caspia Caspian Tern- formerly in the genus Sterna Thalasseus maximus Royal Tern- formerly in the genus Sterna Thalasseus sandvicensis Sandwich Tern- formerly in the genus Sterna SCOLOPACIDAE Scolopacinae Tringa semipalmata Willet- formerly in the genus Catoptrophorus Figure 3. Total number of nests for seabird species recorded in the BNB database from trates the expansion of coverage by the BNB network between SPECIES UNKOWN Some species are inherently difficult to count- they are either exceedingly rare or very secretive. Gull-billed Terns are probably both, and the scant number of recent records is either cause for concern or an indication we need to redouble our efforts when looking for this species. Gull-billed Terns are unpredictable since they exhibit limited fidelity to nesting sites from year to year and can be found in unusual places (e.g. phosphate mines, agricultural areas). They typically nest in mixed-species colonies on sandy barrier or dredge spoil islands, and are occasionally found utilizing gravel rooftops. So next year, try to scan your colonies a little more closely and hopefully you will get lucky and find an oddball tern with a stout all-black bill. Another species for which we have very little data is the Willet. Willets are more common and widespread than Gullbilled Terns but even more secretive in their nesting habits. The adults, themselves, can be highly conspicuous. If you approach too closely to the nest, adults will harshly scold you from an elevated perch. However, observers rarely elicit this response since the nests are often well-hidden and out-of-the-way within dune and marsh vegetation. If you do find yourself face-to-face with a raucous Willet obviously displeased with your presence, you may have a new data point nearby. Tread lightly! FUTURE DIRECTION As we have discussed in this newsletter, monitoring efforts to date by this network of partners have been focused on the management objectives of finding and conserving beach-nesters. We believe that with minor modifications to the database and monitoring protocol we can begin to collect the data necessary to estimate population size and trends for many of our BNB species. Consistency and coordination will be the key to designing a successful population monitoring program- a modest number of surveys need to be conducted at all sites simultaneously each year. Frequency and synchrony of surveys are some of the particulars our network of partners will help to address during the upcoming 2009 season as we continue to develop a survey and monitoring protocol that balances simplicity and value. More on this later... ACKNOWLEDGEMENTS Every single data point helps, and the list of contributors is too long to present in this document. We greatly appreciate all the time and energy spent collecting and getting the data entered into the website. For the regional coordinators who accepted the roll as data entry specialist and entered mountains of data- we can not thank you enough. Feedback. As this was our first summary report of the BNB database, we welcome comments and suggestions on how we can improve similar reports in the future. Please them to Chris Burney, FWC Shorebird Partnership Coordinator (chris.burney@myfwc.com)- Thank you. 4

6 FLORIDA BNB REPORT Species Regions Alln Allc 05n 05c 06n 06c 07n 07c 08n 08c American Oystercatcher Total Haematopus palliatus NC NW S SW Willet Total Tringa semipalmata NC NE NW SW Snowy Plover Total Charadrius alexandrinus NC NW S SW Wilson s Plover Total Charadrius wilsonia NC NE NW S SW All species Total NC NE NW S SW Table 1. Number of shorebird nests and chicks by species, region, and year (ground nests only). 5

7 Species Regions All All his his his his his Least Tern Total Sternula antillarum NC NE NW S SW Black Skimmer Total Rynchops niger NC NE NW S SW Royal Tern Total Thalasseus maximus NC NW SW Caspian Tern Total Hydroprogne caspia NC NW SW Sandwich Tern Total Thalasseus sandvicensis NC NW SW Gull-billed Tern Total Gelochelidon nilotica NC NW SW Laughing Gull Total Leucophaeus atricilla NC NW SW All species Total NC NE NW S SW Table 2. Number of colonial seabird sites by species, region, and year (ground colonies only). For each total, the number of historic sites ( his ) from the Colonial Seabird Survey that were active at least one season between are provided in light gray (Ex. Of the 136 different sites recorded for Least Tern from , 48 were active during the survey). 6

8 FLORIDA BNB REPORT Species Regions Alln Allc 05n 05c 06n 06c 07n 07c 08n 08c Least Tern Total Sternula antillarum NC NE NW S SW Black Skimmer Total Rynchops niger NC NE NW S SW Royal Tern Total Thalasseus maximus NC NW SW Caspian Tern Total Hydroprogne caspia NC NW SW Sandwich Tern Total Thalasseus sandvicensis NC NW SW Gull-billed Tern Total Gelochelidon nilotica NC NW SW Laughing Gull Total Leucophaeus atricilla NC NW SW All species Total NC NE NW S SW Table 3. Number of colonial seabird nests and chicks by species, region, and year (ground colonies only). 7

9 MAP 1 NORTHWEST NORTH CENTRAL NORTHEAST SOUTHWEST SOUTH FWC REGIONS Map 1. FWC Regions 8

10 FLORIDA BNB REPORT MAP 2 Map 2. Coverage? Coverage refers to the extent to which all available habitat was surveyed. The important question is Did our combined efforts result in complete coverage with all sites surveyed? When we compare locations of least tern colonies found during the Colonial Seabird Survey (a systematic statewide survey assumed to represent complete coverage) to least tern colony locations submitted to the BNB Database from , we find that the distribution is generally similar indicating our coverage is relatively comprehensive. Important note: Discrepancies between the two maps may represent gaps in our network (areas not surveyed) or sites that are no longer used by least terns. In order for us to determine the difference, it is extremely important that contributors submit data on sites they have visited even when no beach-nesters are present! LEAST TERN Colonial Seabird Survey small colony (2-10 nests) large colony (200+ nests) LEAST TERN BNB Database 9

11 MAP 3 LEAST TERN 2005 LEAST TERN 2006 small colony (2-10 nests) large colony (200+ nests) LEAST TERN 2007 LEAST TERN 2008 Map 3. Expansion This series of maps illustrates the increased coverage with each successive year. Obviously, the difference between 2005 and 2006 was marked since 2005 was a partial season. The changes between the years following 2005 are more subtle, but new areas were steadily getting included. 10

12 FLORIDA BNB REPORT MAP small colony (2-10 nests) large colony (200+ nests) 7 10 LEAST TERN BNB Database Map 4. Least Tern Sternula antillarum Map of all Least Tern ground colonies (N=136) submitted to the BNB database from with the highest annual count of nests ( ) are listed below and labeled on the map Three Rooker Bar (475) Marco Island City Beach, North End (336) Anclote Key (200) Matanzas Inlet Critical Wildlife Area (223) Kice Island, North end (170) Big Marco Pass Critical Wildlife Area (592) Little Estero Island (181) Anna Maria Island - Jack Egan s (205) Charlotte Beach State Recreation Area (274) Least Tern Colony Lover s Key (150) 11

13 MAP small colony (2-10 nests) large colony (100+ nests) BLACK SKIMMER BNB Database 12 Map 5. Black Skimmer Rynchops niger Map of all Black Skimmer ground colonies (N=75) submitted to the BNB database from with the highest annual count of nests ( ) are listed below and labeled on the map St. George Island Causeway (142) Anna Maria Island - Jack Egan s (333) Anclote Bar (160) Landmark II - Sand Key (250) Bellaire Beach- Key Condo (260) Egmont Key (550) 7. Huguenot Memorial Park (125) 8. Three Rooker Bar (620) 9. TPA Island 3 D (210) 10. Marker 10 - S. Clearwater Harbor (180) 11. Big Bird Island (261) 12. Big Marco Pass Critical Wildlife Area (487) 12

14 FLORIDA BNB REPORT MAP small colony (1-150 nests) large colony (1000+ nests) LAUGHING GULL BNB Database Map 6. Laughing Gull Leucophaeus atricilla Map of all Laughing Gull ground colonies (N=12) submitted to the BNB database from with the highest annual count of nests ( ) are listed below and labeled on the map Huguenot Memorial Park (3000) Audubon Island (6) Bird Island, Apalachicola (69) St. George Island Causeway (2554) Tampa Port Authority Spoil Island 2D (5850) Three Rooker Bar (7850) Richard T. Paul Alafia Bank Sanctuary (150) TPA Island 3D (4700) Egmont Key (32,450) 13

15 MAP small colony (1-10 nests) large colony (1000+ nests) ROYAL TERN BNB Database Map 7. Royal Tern Thalasseus maximus Map of all Royal Tern ground colonies (N=9) submitted to the BNB database from with the highest annual count of nests ( ) are listed below and labeled on the map. Sandwich Tern and Caspian Tern distribution very similar. 1. Huguenot Memorial Park (500) 7. Egmont Key (5,572) 2. Lanark Reef (424) 3. Bird Island, Apalachicola (375) 4. St. George Island Causeway (1,457) 5. Three Rooker Bar (700) 6. TPA Island 3 D (420) 14

16 FLORIDA BNB REPORT MAP 8 AMERICAN OYSTERCATCHER Single ground nests BNB Database Map 8. American Oystercatcher Haematopus palliatus Map of all American Oystercatcher nest locations submitted to the BNB database from

17 MAP 9 SNOWY PLOVER Single ground nests BNB Database Map 9. Snowy Plover Charadrius alexandrinus Map of all Snowy Plover nest locations submitted to the BNB database from