Seabird Monitoring Field Guide For
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Seabird Monitoring Field Guide Seabird Monitoring Field Guide A field guide to monitoring seabirds in the British Virgin Islands, West Indies Contents Why count seabirds Why count seabirds....................................................2 What to count and where…........................................3-4 When to count............................................................5 How to count..............................................................6 Summer breeding seabirds.........................................7-10 Winter/asynchronous breeding seabirds...................11-13 Recording ............................. .....................................14 Sample recording form...............................................15 Citation: Soanes LM, Zaluski S, Bright JA & Green JA (2014) Seabird Monitoring Field Guide: A field guide to monitoring seabirds in the British Virgin Islands. Jost Van Dykes Preservation Society. BVI , West Indies. This field guide was produced as part of the Darwin Plus project Using Seabirds for Caribbean Marine Planning. The project was led by the University of Liverpool in partnership with the Royal Society for the Protection of Birds (RSPB), Jost Van Dykes Preservation Society and BVI National Parks Trust, with support from the BVI Government’s Department of Conservation & Fisheries. Seabird Monitoring Field Guide Contents Why count seabirds The British Virgin Islands are home to 15 breeding seabird species, with two populations reported as being of global importance and 8 populations as regionally important. As top marine predators, seabirds are an important indicator of the health of the marine ecosystem as a whole. Regular and repeatable counts are crucial to monitor populations, assess their health and target conservation action 3 Map of British Virgin Islands (see table on next page for island names) Seabird Monitoring Field Guide 2 What to count and where? Previously recorded breeding species on each of BVI’s islands and cays. NOTE this list is not exhaustive, and colonies move between years, particularly tern species Magnificent frigatebird Brown booby Brown pelican Brown noddy Roseate tern Sandwich tern Bridled tern Least tern Cayenne tern Gull-billed tern Common tern Red-billed tropicbird White-tailed tropicbird Laughing gull Audubon's shearwater 1 Anegada 2 Beef Island 3 Broken Jerusalem 4 Carrot Rock 5 Carval Rock 6 Cistern Rock 7 Cockroach Island 8 Cooper Island 9 Deadmans Chest 10 East Seal Dog 11 Eustatia 12 Fallen Jerusalem 13 George Dog 14 Ginger Island 15 Great Camanoe 16 Great Dog 17 Great Thatch 18 Great Tobago 19 Green Cay Seabird Monitoring Field Guide Magnificent frigatebird Brown booby Brown pelican Brown noddy Roseate tern Sandwich tern Bridled tern Least tern Cayenne tern Gull-billed tern Common tern Red-billed tropicbird White-tailed tropicbird Laughing gull Audubon's shearwater 20 Guana Island 21 Jost Van Dyke 22 Little Camanoe 23 Little Jost Van Dyke 24 Little Thatch 25 Little Tobago 26 Marina Cay 27 Mosquito Island 28 Necker Island 29 Norman Island 30 Pelican Island 31 Peter Island 32 Prickly Pear 33 Round Rock 34 Salt Island 35 Sandy Cay 36 Sandy Spit 37 Scrub Island 38 The Indians 39 Tortola 40 Virgin Gorda 41 Watsons Rock 42 West Dog 5 43 West Seal Dog Seabird Monitoring Field Guide 4 When to count? J F M A M J J A S O N D Brown booby Magnificent frigatebird Red-billed tropicbird White-tailed tropicbird Brown pelican Laughing gull Sooty tern Bridled tern Royal tern Roseate tern Sandwich tern Least tern Brown noddy Audubon’s shearwater Yellow indicates months when breeding may occur, ticks indicate best time to survey, some asynchronous species will require two counts per year Seabird Monitoring Field Guide When to count? How to count BOAT-BASED COUNTS Given the large number of cays to survey and the inaccessibility of most within the British Virgin Islands, the easiest way to survey is by boat Circumnavigate each island slowly ideally between 06:00-10:00 or 15:30-18:00 to coincide with peak seabird activity Record number of adults associated with the colony (e.g. landing in colony, territorial behaviour displays, carrying fish) Do not record those that appear just to be feeding close to or flying past the island LAND-BASED COUNTS Actual counts of Apparently Occupied Nests will provide the most accurate population counts, so where possible islands and cays should be surveyed by foot and nests counted Locate seabird nesting areas by circumnavigating islands by boat Walk in a team of three (two surveyors and one recorder) in parallel transects throughout the colony covering all suitable looking habitat Record contents of nests as: 1) Incubating adult 2) Egg 3) Young chick 4) Large chick 5) Fledged chick It is NOT necessary to record adult numbers if you are thoroughly 7 and systematically recording nests. Seabird Monitoring Field Guide 6 Summer breeding seabirds - common breeders Audubon’s shearwater Rarely observed during daylight Leaves and returns to breeding site during darkness Nests in crevices in rocks, under boulders and cliff edges Ideally all suitable habitat should be searched for nests Incubating adults often respond to call “playback” Play male and female call for 30s every metre in suitable habitat and listen for responses for a further 30s Incubating adults or chicks may also be seen by looking into crevices or under boulders Photo: L. Soanes Photo: LouisePhoto: Soanes Richard Brown Photo: Richard Brown Adult with egg Chick Seabird Monitoring Field Guide Summer breeding seabirds - common breeders Laughing gull Nests are difficult to locate and are found on the ground, often under bushes, or in rocky outcrops Photo: Lawrence Scott Brown Noddy Photo: James Kimani Nest on cliff edges, under boulders and on top of vegetation Bridled tern Black upper body and white underparts Photo :Henry Cook Only confused with similar sooty tern which has not been reported breeding in BVI (white eye stripe stops at eye on sooty tern but extends beyond on bridled tern) Photo: Lawrence Scott Photo: Blundelwood Photo: Alan Vernon IN FLIGHT Photo: Katseye116 Photo: MJ Anderson 9 Photo: Peter HiIl Laughing gull Brown noddy Bridled tern Seabird Monitoring Field Guide 8 Summer breeding seabirds - common breeders Summer breeding seabirds - occasional/rare Roseate tern Red legs Black bill with red base Long, forked tail Length 36 cm Sandwich tern Black bill with yellow tip Photo: Lisa Lawley All black forehead Length 38 cm Royal tern Largest of terns Orange bill Shaggy crest Royal (orange bill) & sandwich (black bill) Length 50 cm Photo: Len Blumin Least tern Smallest breeding tern Yellow bill White above eye Yellow legs Length 23 cm Photo: Scott Hecter Seabird Monitoring Field Guide Photo: Scott Hecter Summer breeding seabirds - common breeders Summer breeding seabirds - occasional/rare Common tern Similar to roseate tern but lacks deeply forked tail and has more red on bill Cayenne tern Common Yellow bill and black crest Gull-billed tern Thick black bill i Black head Royal (left) cayenne (middle) and sandwich Photo: Bob Devlin IN FLIGHT Roseate Photo:Common Paul Ritchie Sandwich Photo:USFWS Photo: J.N Stuart Photo: Paul Ritchie Least Gull-billed 11 Royal (non-breeding) Photo: Haskor Photo: Eric Houlii Photo: Chrisine Fusco Seabird Monitoring Field Guide 10 Winter/ asynchronous breeding seabirds Winter/ asynchronous breeding seabirds Magnificent frigatebird Breed year-round (with peaks Oct-Jan) Sensitive to disturbance! Birds eat unattended eggs and chicks Take series of photographs of the colony from a vantage point on top of the ridge of Great Tobago Open photographs on computer, mark and count apparently occupied nests as any adult bird seen sat at colony or any unattended chick. Photo: Susan Zaluski Photo: Susan Zaluski Female Breeding male Photo: Photo: Susan Zaluski Photo: Lawrence Scott Juvenile Flying female Seabird Monitoring Field Guide Winter/ asynchronous breeding seabirds Winter/ asynchronous breeding seabirds Tropicbirds Breed year-round Nest under boulders, in crevices and cliff edges Nests can often be identified by smell or alarm call c Red-billed tropicbird Photo: K M cormack Distinguished by red bill and mostly white upper parts Photo: tinyfishy White tailed tropicbird Yellow bill & bold black wing markings For boat-based counts record birds entering cliff face during hours of peak daily activity (from 15:30 to 17:30) Photo: Farah Mukhida Photo: Bonxie88 Photo: Nancy Pascoe 13 Red-billed adult Red-billed chick White-tailed adult Seabird Monitoring Field Guide 12 Winter/asynchronous breeding seabirds Recording data Brown Pelican Count adults and chicks A nest can contain 1-3 chicks, but can be hard to distinguish, record total Photo: photomatt28 number of chicks then report breeding Breeding adult pairs as a: minimum (if every nest had 3 chicks) and maximum (if every nest had 1 chick) Photo: Alan Vernon Brown Booby Adult in flight Nests on ground Adults have brown upperparts and white underparts Chicks white or fluffy white and brown, immature all brown Photo: Susan Zaluski Photo: Susan Zaluski Photo: Susan Zaluski Brown booby adult Chick Juvenile Seabird Monitoring Field Guide Winter/asynchronous breeding seabirds Recording data See example recording form on back page Use one form per species per site Remember to write the date and site on all forms! Record stage of breeding where possible to help plan timing of future surveys. For more details on seabird