BIMONTHLY BULLETIN of the CAYMAN ISLANDS DEPARTMENT of ENVIRONMENT ‘S TERRESTRIAL RESOURCES UNIT

Sophie O’Hehir has recently joined the Back at the office Sophie has been TRU thus replacing Jessica Harvey as digising long-standing data taken from one of the Department’s Terrestrial the Central Mangrove Wetland by Fred Research Officers. Burton in order to calculate volumes of carbon sequestering. This data es in Her main dues will consist of directly with the Terrestrial Protected undertaking the DoE’s biological Area Nominaons and offer a measure monitoring, assisng vising sciensts of the ecosystem services provided by with projects and execung TRU this nominated area. Addionally iniaves. Sophie has been going through the drone footage taken for the Seabird project to idenfy Brown Booby nests Coming originally from the UK with a along the bluff and the South Beach of Zoology degree from Swansea Cayman Brac. University, Sophie has worked in the UK,

Costa Rica, and Ascension Island (part of the St. Helena Brish Overseas Sophie hopes to connue to meet lots Territory). Having previously worked of people interested in and involved with charies, NGO’s and the private with Cayman’s fauna and ﬂora, so sector, Sophie is very excited to join the please feel free to introduce yourself if endeavours of the Cayman Islands’ you get the opportunity! Department of Environment.

While having had hands-on experience with a wide variety of flora and fauna in both temperate and tropical environments, her most notable experience involves reples, bats and marine turtles (including leatherback and green turtles). So far with the Department, she has been undertaking the biennial Cayman Brac Parrot survey and taken part in the Green Iguana control efforts on the Sister Islands with her colleague Jane Haakonsson. She has further assisted Dr Rhiannon Meier in the Darwin funded seabird project where she was involved in handling and tagging both Red-footed Boobies and Magnificent Frigate-birds in the Booby Sophie handling a Frigate-bird in the recent Pond Reserve. seabird colony work on Lile Cayman.

Flicker Bulletin # 30 – MAY / JUNE 2017 TRU’s Biennial Bird Survey

While the role of a conservaonist is Obtaining density or size esmates for oen diverse and complicated, most animal populaons can be problemac management of wildlife populaons and me consuming and even a single oen boils down to two relavely survey will do lile but give you an simple quesons: isolated snapshot in me, which is oen of lile value. That is why long-term • How many animals do I have in monitoring programmes are in place the populaon? within well established conservaon organisaons around the world. • And is this number going up or down? The DoE has several monitoring programmes for both marine and These quesons may seem simple, but terrestrial species of Cayman. Marine they are of utmost importance to assess species which are being rounely the trend of a wild animal populaon at monitored include the Queen Conch a given moment in me. Once obtained, (Strombus gigas), the Nassau Grouper this trend can be related to the various (Epinephelus striatus), sharks, corals and factors inﬂuencing the populaon turtles. Terrestrial species include the whether or not management acons Blue Iguana (Cyclura lewisi), the Sister are performed. In other words, with Island Rock Iguana (Cyclura nubila baseline data it is possible to asses how, caymanensis), both Cayman Parrot for example, management or threats subspecies, seabird colonies and, for aﬀect the abundance of individual example, the nave Inkberry (Scaevola animal species. plumieri).

The White-Crowned Pigeon (Patagioenas leucocephala) is an indigenous species distributed throughout the Western Caribbean, the Central American Caribbean coastline and the southern p of Florida. Flicker Bulletin # 30 – MAY / JUNE 2017

The TRU recently finished its biennial a seemingly thriving populaon may be bird survey which is carried out every more subjecve and vulnerable to other year on Grand Cayman and threats than first meets the eye. The Cayman Brac respecvely, in percentage of “floaters” may be as high cooperaon with the as 60 – 80% of the populaon. For US Fish and Wildlife Service. Originally example, in Cayman Brac the 2009 July started as the monitoring of both survey showed only around 25 breeding Cayman Parrot subspecies (the Grand pairs in a populaon of 291 (95% CI = Cayman Parrot and the Brac Parrot), this 203 to 417) birds. survey now includes several dove species, the Northern Mockingbird Studying populaons before and aer (Mimus polygloos), Vitelline Warbler external events, such as hurricanes, is (Setophaga vitellina) and the Red- equally important. Results give legged thrush (Turdus plumbeus). managers a picture of the resilience of a given populaon. Using again the Brac Surveys are carried out before (March) Parrot populaon as an example, and aer (July / August) reproducon surveys showed 565 (95% CI = 409 to for the main focal species, i.e. the 782) birds in July 2008, before hurricane parrot, in order to establish the number Paloma and only 260 birds (95% CI = of breeding pairs. This is done because 199 to 441) aer Paloma in March 2009. parrots oen have a high percentage of This number has been steadily non-breeding birds in the populaon increasing since, to 772 (95% CI = 603 to referred to as “floaters”, which is why 989) birds in July 2015 which subjecver suggestssuggest su

The Cayman Brac Parrot (Amazona leucocephala hesterna) is an endemic subspecies of the Cuban Parrot, and will, in me, evolve into its own full species on Cayman Brac. Flicker Bulletin # 30 – MAY / JUNE 2017 suggests an impressive but slow resilience through the use of density recovery from a single hurricane event. maps. These maps inform managers If, for example, two consecuve about increased aggregaon which is hurricanes were to hit Cayman Brac, we seen in most developed islands species. now know that with a populaon As available feeding and nesng habitat decreased by around 50% (and thus very decreases (as direct results of few remaining breeding pairs) aer the development), endemics inhabit fewer ﬁrst hurricane, this subspecies would areas in higher densies. This can be likely go exnct aer the second. measured through “dispersion parameter b”, which assigns a randomly distributed species with a b-value of 1. Monitoring surveys can furthermore be Values above 1 shows increased used to assess factors inﬂuencing “clumping”. See below. resilience, such

Species Before (b) Aer (b)

Red-Legged Thrush 2008 = 3.38 2015 = 6.97

Brac Parrot 2008 = 1.11 2015 = 3.14

Grand Cayman Parrot 2005 = 1.68 2014 = 6.07

The table shows how 3 endemic subspecies are increasingly being “pushed out” of suitable habitat.

Cayman Brac Parrot density maps visually showing a comparison between the distribuons in 2010 and 2012. The dispersion parameter b is increasing and gives a numerical value to the aggregaon. 2017 data is pending analysis.

Flicker Bulletin # 30 – MAY / JUNE 2017 While integrang monitoring efforts to To this end is important to remember inform management decisions may that certain populaons (like that of the seem obvious when protecng a species WCP) cannot be considered such as the parrot, other bird species demographically closed populaons need to be monitored to inform take unlike, for example, the Cayman Parrot limits. These are our game-birds. populaons. alternavs The Naonal Conservaon Law outlines Seasonal and annual differences in the two current game-bird species of abundance may reflect births and the Cayman Islands, namely the Blue- deaths but also immigraon and winged teal (Anas discors) and the emigraon as WCPs can move between White-winged dove (Zenaida asiaca). Grand Cayman, the Sister Islands, Take limits and seasons can only be set Jamaica and Cuba. Such fluctuaons are with an understanding of how mostly indirect results of varying levels populaons are currently doing and of rainfall and thus food abundance. The therefore how harvesng can be TRU is therefore keeping up to date with maintained sustainably. other Caribbean monitoring events of the species and collang rainfall data to get a beer understanding of WCP For example, TRU has been monitoring migraons. the White-crowned pigeon (WCP) populaon on both Cayman Brac and For a full report on TRU’s bird surveys Grand Cayman since 2011 in and how results are used, please contact collaboraon with Dr. Frank Rivera- the editor, page 2. Milan from the U.S. Fish and Wildlife Service. When comparing the Grand Cayman density and populaon esmates from 2011 to pre- and post- reproducve surveys in 2014, a significant decrease can be seen despite an unchanged detecon probability. In 2011 we recorded 0.17 pigeons per ha in a study area of 15,550 ha (2,708 pigeons) which compared to 0.05 and 0.062 pigeons per ha (775 and 906 pigeons) in March and August 2014 respecvely, providing a significant decrease of almost 70%.

As overhunng is the primary threat for the WCP it has consequently been removed from the game-bird list according to the Naonal Conservaon Law. As the populaon monitoring White-winged dove (Zenaida asiaca) connues, protecon is carefully re- remains on the game-bird list unlike the evaluated and updated. White-crowned pigeon.

Flicker Bulletin # 30 – MAY / JUNE 2017

Green Iguana Control on Cayman Brac

Lile introducon is needed when it strategy to prevent this highly invasive comes to the invasive nature of the species from geng a stronghold on Green Iguanas (Iguana iguana). They Lile Cayman and Cayman Brac as we are currently everything but a rare have seen it on Grand Cayman. sighng around Grand Cayman and very few people need convincing that this With over 35 sighngs of Green Iguanas species is bad news: from the keen on Lile Cayman since 2007 and many gardener, the pool owner, the naturalist more on Cayman Brac, it is clear that the to the average driver; green iguanas biosecurity between all three islands prove an overabundant nuisance. For needs to be enforced and ongoing managers of general infrastructure, response measures need to be airports, agriculture, landscaping, implemented. “Green Iguana be natural resources and local housing, the Gonna”, established on Lile Cayman by species can cost hundreds of thousands Mike Vallee and Ed Houlcro, has of dollars in damage annually. responded to all known sighngs of Green Iguanas and have had over 90% In our small terrestrial unit, we are of reports lead to capture and disposal parcularly concerned with the negave of Green Iguanas. However, unl impacts Green Iguanas have on our recently the same community response nave ecosystems and their was not running on the Brac. biodiversity. Thus establishing a connuous and sustainable control The TRU therefore launched a 5 day cull operaon on both of the Sister Isles is on Cayman Brac in April to get an essenal part of the overall community support. strategyov

Jane Haakonsson, Bonnie Sco Edwards and Sophie O’Hehir all holding up Green Iguanas captured during night searches in Spot Bay.

Flicker Bulletin # 30 – MAY / JUNE 2017 Following community meengs and A presentaon was held at the Brac Port school talks held in October last year, to enforce the urgent need for the cull effort included a volunteer biosecurity efforts. While the first briefing on April 8th, 2017, at Bonnie introducon of Green Iguanas to Sco Edward’s house. It was well Cayman areas, or. Brac may have happened aended with 5 DoE staff members through the importaon of caged present; Jane Haakonsson, Mark Orr, animals, a connuous stream of Green Erbin Tibbes, Sophie O’Hehir and Mike Iguanas are entering the island through Guderian, the “Green Iguana be Gonna” container traffic from Grand Cayman. founders; Mike Vallee and Ed Houlcro Eight members of Port staff were taught and 12 volunteers. A presentaon was about the effects of Green Iguana made to inform residents of the scale of ffffffffff the Green Iguana problem on Grand Cayman and DoE’s associated culling efforts in 2016. Aendees were taught effecve search and catch techniques, humane culling methods, proper disposal procedures as advised by DEH, and an outline of known sighngs was discussed and accompanied by maps which were handed out.

Aer the meeng the first search began and lasted from 7 pm to 3 am as night searches prove the most effecve when hunng for Green Iguanas (as they become extremely docile due to the drop in temperature). 3 Green Iguanas were caught by noose and culled humanely during the first search. One female carried 16 undeveloped egg follicles.

9 DoE lead searches were subsequently performed in known high density areas (mainly in Spot Bay), one every morning and evening unl mid-day on April 13th. Volunteers occasionally accompanied the team and all were equipped with torches, head lights and nooses provided by the DoE and “Green Iguana be Gonna”. A total of 10 Green Iguanas were caught during the cull, the females Aer the presentaon at the Port a male Green carrying a total of 36 eggs . Iguana was caught on the compound atop an old crane, oﬀering valuable ﬁrst-hand experience in handling this species.

Flicker Bulletin # 30 – MAY / JUNE 2017 overabundance and all were explained A response team of volunteers and a how best to capture, noose, handle and WhatsApp group now deals with every humanely cull Green Iguanas. The DoE single sighng and Green Iguana report le several nooses for that purpose with and the TRU would like to specifically the Port staff and Iguana Hotline cards thank the following volunteers for all were distributed. their precious me and effort in establishing and comprising this During and aer the cull an extensive response team: effort was made to reach out to the Brac community, through door-to-door visits, Bonnie Sco and Gene Edwards, Keino speaking to Public Works, Lands and Daley, Lance Boley, Debra Vascik, Survey, the RCIPS, car rental companies Sheldon Sco, Miha Popovic and Jesse. and more, handing out Iguana Hotline cards as well as flyers on how to tell the difference between Green Iguanas and the endemic Sister Island Rock Iguanas. For the laer, please see the excellent flyers created by Elaine Powers on page 10 and 11 and feel free to contact the editor (page 2) if an electronic version is required for prinng.

Iguana Hotline Cards were handed out by the team during the cull and ongoing outreach to the local High School has been carried out by TRU staﬀ Jane Haakonsson.

Flicker Bulletin # 30 – MAY / JUNE 2017

KNOW YOUR NATIVES YELLOW MASTIC

Yellow Masc (Sideroxylon in December or June. Flowers are foedissimum), oen known as “false heavily scented and the small fruits masc” and not to be confused with the ripen to a yellow colour and contain a endemic Black Masc (Terminalia single large brown seed. eriostachya), is one of our largest nave crically endangered trees. The single straight trunk is comprised of heavy and strong heartwood hence Found in high elevaon prisne forests, Yellow Masc was valuable for its this tree can be seen on the Masc Trail mber in the Bahamas and the West on Grand Cayman and is somewhat Indies and has been used for abundant on the Bluff of Cayman Brac. cabinetwork and boat mber. While It grows much taller than surrounding Yellow Masc trees were heavily logged vegetaon to a height of around in mes gone past they can sll be 10-15m (33-50 ). Each tree doesn’t enjoyed in Cayman. They are excellent flower every year but flowering usually shade trees but very slow growers. occurs in

Le: ripe Yellow Masc seed and right: full tree with its straight trunk. Photo by Ann Staﬀord.

Flicker Bulletin # 30 – MAY / JUNE 2017