MONTHLYMONTHLY BULLEBULLETINTIN ofof thethe CAYMANCAYMAN ISLANDSISLANDS DEPARDEPARTTMEMENTNT ofof ENVIRONMENTENVIRONMENT TETERRESTRIALRRESTRIAL ECOLOGYECOLOGY UNUNIITT

with parents often raising fewer than two chicks per year. This means that the killing of adult parrots is especially damaging, because if the death rate of adults overtakes the birth rate, the population will decline.

Parrots are secondary cavity nesters; meaning they are dependent on a limited supply of existing cavities in forest trees, in Cayman Parrot which to make their nests. Furthermore, Cayman parrots continue to suffer from Brac students discuss illegal nest poaching, which reduces the number of juveniles joining the population parrots… each year. Nesting cavities are often damaged in the process, rendering the nest Just before the Christmas break, enviro‐ site useless for future nmental science students at University reproduction. Continuing forest clearance College of the (Cayman is another major factor driving parrots into Brac), came together to discuss key decline. conservation issues, regarding our two endangered parrot populations. The class For many people parrots are colourful, discussion, guided by the Department of charismatic birds, and a joy to encounter. Environment centred on the extinction Students agreed that parrots are worth pressures affecting our parrots: poaching, preserving, but also concurred that they shooting, and deforestation. Students can damage fruit crops. A sound economic were keen to know why the parrots are solution, which serves the financial vulnerable to unnatural deaths and habitat interests of fruit growers, and facilitates the damage, and why, despite legal protection, these pressures continue to chip away at their numbers.

The students were presented with evidence of why the biology of our wild parrots makes them vulnerable to environmental changes. Adult parrots are good survivors, and are long‐lived, but it Students learning about takes several years before they reach plants with Wallace Platts maturity and breed. Reproduction is slow, Image: Martin Keeley continued protection and preservation of the parrots, is necessary. The students took away with them, an example of the complex and conflicting factors involved in a real ecological issue. Most already knew that the parrots are legally protected, but gained a better understanding of why these issues continue. The Cayman Islands is in need of an updated law to preserve our parrots. We also need economic incentives to assist fruit farmers, and ease the financial burden of environmentally sound Wallace Platts Image: Wallace Platts stewardship of Cayman’s natural heritage.

For a related parrot article ‘Storm Survivors’ volunteer, has spent the last 17 years in see the Oct 2009 issue of Flicker. pursuit of a greater understanding of the natural environment. He has given lectures and written a number of articles about the Naturenotes.. ecology and geology of the island. The new blog provides a simple way of making this If you have ever wanted to know more information permanently available. about the wildlife of Cayman Brac, a new blog, naturenotes19n79w.ky may be what Wallace’s blog is a first link for people you’re looking for.” Created by Mr. interested in Cayman Brac’s natural history. Wallace Platts after calls from local The site is dynamic and regularly updated residents, the site is dedicated to all things with photographs, general observations, natural on Cayman Brac. short articles and poetry.

Mr. Platts, a member of the National Trust Posts are gently scientific and easy to read; for the Cayman Islands and prominent “it’s about nature —the dry, deciduous limestone forest, the high plateau and the skirt of low‐lying land; about shores, birds, plants, the shallows, the sea and the precious few ponds and lagoons. It’s about the interaction of all of these —and about the human inhabitants who arrived about Editors 1833, changing everything.” Kristan D. Godbeer Mat DaCosta‐Cottam Whilst predominantly covering Cayman SiânRowland Brac, some photographs and articles TEXT relevant to and Little MatPHOT DaCostaOS ‐Cottam Kristan D. Godbeer © Cayman are included. NatureNotes aims to PHOTOSunless credited otherwise Consolea millspaughii var. caymanensis promote a more joined up view of the Image: Mat DaCosta‐Cottam Kristan Godbeer three Cayman Islands.

Department of Environment PO BOX 486, 580 North Sound Rd. GRAND CAYMAN KY1‐1106 TEL: (345) 949‐8469 www.DoE.ky www.CaymanBiodiversity.com CONTENTS

In this issue

1 Brac students discuss parrots Kristan D. Godbeer & Mat DaCosta‐Cottam

Why are our parrots endangered?

2 Naturenotes 1 2 Siân Rowland

New enviro‐blog for Cayman Brac

4 Mail Box

Your views and observations. 9 Creature Feature 5 Mat DaCosta‐Cottam www.CourtneyPlatt.com Learn about Cayman snakes and scorpions. Fact sheets posters for your 4 wall.

7 Articles

Effects of Habitat Modification on the Foraging Activities of 7 Insectivorous Bats, on the Island of Grand Cayman

Paul Watler

18 Essays and Notes

Introduction of Captive‐bred White‐Crowned Pigeons, Patagioenas leucocephala, in to the Wild Via Soft Release 18 Peter Borg 3 Flicker (2009) 6

Letters should be addressed to: ‘Flicker’ Department of Environment PO BOX 486 Cayman Islands KY1 1106 Mail Box Or Email: [email protected]

Thanks.. Reply.. Dear Editors, Dear Vanda Thanks for such refreshing articles. They are Thank you very much for this encouraging most informative and educational. I’ve sent feedback! Yours was one of several letters we them to my personal email so my children will received from people interested in using the learn more about their environment, and how Native Tree Nursery to introduce a low-cost / they can assist with a greener & healthier one low maintenance element to their garden also. landscaping. The nursery, which is based at the Botanic Park, has a great selection of I’ve often wondered how the local soldier crab different trees, shrubs and flowers specially survived when changing their shells. So now selected to thrive under the most challenging I’ll try to make a conscious effort to help them conditions – from swamp to sandpit. All the with collecting whelk or other shells in varied plants are fully labeled with details of their sizes. Now I do love jewelry made of almost growing requirements, final size and shape, anything natural including the whelk shell, so and information about the birds and butterflies I’ll share the whelk shells and spread the word they will attract to your garden. To see a around. selection of the stock, check out http://www.caymanbiodiversity.com/resources The first article has given me new motivation /plants/native-tree-nursery/# and click on the to go out to beautiful North Side and visit the images. Following the success of the New Botanic Park for local plants. This is my Year sale of Native Trees at the Park last number one article in this issue, as I’m month, we are planning to extend the 25% currently in the process of landscaping my discount into February. Happy gardening! yard and developing my home garden. Thanks again and I look forward to the next one. Mat Kind regards,

Vanda Powery Grand Cayman

4 SNAKE SPECIAL

Cayman has five native snakes: the Cayman Racer Alsophis cantherigerus, the Cayman Ground Boa DON’T Tropidophis caymanensis, the Water Snake Tretanorhinus variabilis , and the Cayman Blind Snake Typhlops caymanensis and Typhlops epactia. Two introduced species are also common: the Corn PANIC! Snake Elaphe guttata (a popular pet species from North America) and the tiny Brahminy Blind Snake Ramphotyphlops braminus (probably introduced from Florida in plant pots). None are dangerous to humans, cats or dogs. This guide focuses on the three species causing most concern. Cayman Ground Boa (Lazy snake) A miniature boa, rarely exceeding 18 inches, found only in the Cayman Islands.

ID: Look for triangular head, “chubby cheeks”. Colours vary from chocolate brown to pale, almost white.

FEAR FACTOR: Often mistaken for “baby rattlesnakes” on account of their “diamond back” pattern, and a light, creamy yellow tip to their tail.

FACT: When snakes flick their tongues, they are tasting the air ‐ no cause for concern!

Corn Snake Growing to around 5 feet in length. Highly variable in colour.

ID: Most specimens captured around George Town exhibit light brown and grey bodies with bold red patterning.

FEAR FACTOR: Bright colouration can often indicate poisonous or venomous species, however the Corn snake, like Cayman’s native snakes, is harmless to people and pets.

Cayman Racer Fast‐moving, growing to 5‐6 feet.

ID: Generally dark brown with pale belly, flecking with dark and pink scales.

FEAR FACTOR: When threatened, may raise its head and flatten its neck, causing confusion with a cobra. Fully grown adults can appear formidable.

FACT: To scare a snake from your path, stamp your feet on the ground. It will detect the vibrations and move away. SCORPION SPECIAL

The Cayman Islands is home to three species of scorpion: Centruroides gracilis, found throughout tropical TAKE America and the Caribbean, is by far the most common. Isometrus maculatus is found in tropical areas CARE! throughout the world, but is apparently uncommon in Cayman. Last, and by no means least, the Cayman Islands has an endemic scorpion, Heteronebo caymanensis, which is found nowhere else on the planet.

Cayman endemic scorpion Heteronebo caymanensis (left) SCORPION FACTS: and the common Centruroides gracils (right)

VENOM: Scorpion venom, delivered by a sting from the end of the tail, may contain a number of toxins. Scorpions can control how much venom they release, and may even deliver a venom‐free “dry” sting. There has never been a recorded death resulting from scorpion envenomation in the Cayman Islands, however, stings can be extremely painful. Allergic reactions are always a possibility. As is the case with most venoms, children are more susceptible due to their smaller body size. The elderly and infirm may also exhibit a more severe reaction. If you are stung, seek medical attention.

DETRRING SCORPIONS FROM ENTERING YOUR HOME: Once established, scorpions can be difficult to remove. Prevention is better than cure. Scorpions are attracted to nooks and crannies. Avoid piling branches, timber, garden rubbish or construction debris near doorways. Gaps around doors may be reduced with rubber or brush‐borders. Scorpions are great climbers. Ensure windows, roof tiles and soffits are secure. If you suspect you have scorpions, wear gloves when checking nooks and crannies (bookshelves, drawer units, laundry piles etc.) Commercial pest controllers can assist with removals.

If you see the rare Cayman endemic Heteronebo caymanensis, please call DoE on 949‐8469. Flicker (2010) 6, 7- 17

Articles

Effects of Habitat Modification on the Foraging Activities of Insectivorous Bats, on the Island of Grand Cayman

Paul Watler National Trust for the Cayman Islands, Grand Cayman [email protected]

Bats on Grand Cayman are threatened by the increasing pace of development. Some bat species are able to tolerate human activities and thrive in modified habitat, while others seem to be relegated to unmodified, natural areas. Heretofore, there has been no survey performed which specifically compares bat foraging activities in modified habitats with their foraging activities in natural habitats. This survey recorded and identified bat species with Anabat equipment. The resulting data indicates that the level of habitat modification indeed affects the extent to which bats will utilize those areas in foraging. Increasing habitat modification also results in a decline in species richness. This suggests that even though certain species are tolerant of modified habitat when roosting, the majority of Grand Cayman’s bats will in fact fly to unmodified, natural habitats for feeding. Keywords: acoustic survey, Anabat, bats, Cayman Islands, foraging patterns, habitat modification, Microchiroptera.

Introduction The ability of any given species to persist Humans are often implicated as the main in the face of such changes depends on its explanation for biodiversity loss [1]. In capacity to adjust to such modifications: particular, human modification of natural its level of tolerance. The tolerance habitats is listed as one of the direct expressed by different species to human causes [1 & 2]. The scope of the changes activities is quite difficult to quantify, wrought on a landscape may range from however, since such activities may be habitat degradation to habitat advantageous for one species whilst fragmentation, or in the most dire cases, deleterious for another. outright destruction. Islands are especially susceptible to extinctions and Bat species (Fig. 1), for instance, exhibit a extirpations as a result of ecologically range of responses to habitat modification detrimental human activities, since and anthropogenic structures. There are endemic island species typically have no several accounts relating the foraging means of migration [1].

7 Bat foraging and habitat modification – P. Watler

activity of bat species in urban areas [3, 4, 5]. chiefly by development, habitat modificat- ion has already had a detrimental effect on A survey conducted by Grindal and Brig- several of Grand Cayman’s endemic [3] ham (1998) , found that bat activity species; and is probably the single biggest increased as a result of small scale tree threat to Cayman bats [9]. Development is harvesting. A positive relationship slated to increase in the coming years, between urban illumination and bat with plans having already been outlined activity has also been observed for some for new schools, roads, and other species, since the insects they hunt infrastructure. Consequently, the persist- [4, 6, 7] congregate around light sources . ence of bat populations in the Cayman This is in contrast to a recent study by Islands would greatly benefit from long [8] Stone et al. (2009) , which reported a term monitoring [10]. Tracking bat species reduction in activity as a result of artificial abundance and species richness as lighting. Thus, the effect of habitat development progresses would ensure data modification on bat activities is largely is available for comparison after natural dependant on the tolerance of the part- disasters (such as seasonally occurring icular species in question. Being driven hurricanes). It could also yield a concrete

Figure 1. Top left: E. fuscus; Top right: L. borealis; Bottom left: M. molossus tropidorhynchus. Images: Courtney Platt www.courtneyplatt.com Bottom right: A. jamaicensis parvipes. Image: Paul Watler.

8 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler

post-Ivan assessment of those bat Grand Cayman utilize natural habitat types populations for which data may still be for foraging more often than modified deficient. habitats; secondly, that bat species richness declines in response to increasing habitat The data from a monitoring program, as modification. Note that the term “habitat” proposed by the survey described in this in this report will refer particularly to study, would assist with answering certain areas and the extent to which they important questions. How do the 5 bats have experienced anthropogenic species surveyed cope with the current modification. scale of habitat modification on Grand Cayman? Materials and Methods Though certain species tolerate An acoustic monitoring survey was carried modification of roost sites, their nocturnal out to test the effects of habitat type on bat habits may require them to leave the urban foraging patterns, testing the hypothesis areas to avoid the lights that typically that bats rarely forage in developed, accompany man-made structures. Since densely populated areas in favor of lights are known to attract insects, it’s just undisturbed, natural habitat. Survey sites as plausible that insectivorous bats have were assigned to one of three habitat types learned to utilize developed areas for (near natural, partially modified and urban) foraging. Band has already reported that based on the extent of modification by most species are better suited to foraging human activity. A total of 30 transects were in natural dry forests or wetlands than walked in each habitat type. developed or fragmented habitat [9]. Previous surveys, however, have focused Near Natural areas consisted of primary primarily on differentiation between and secondary habitat which was various natural habitat types, with completely or mostly untouched: such as anthropogenic habitat comprising the trails through dry forest, paths into karst minority of survey sites. shrubland, dikes across mangrove swamps, or pasture and other agricultural areas. To This study, by contrast, attempts to qualify as Near Natural, human examine foraging patterns by delineating infrastructure constituted 10% or less of the habitats based on the amount of study area. As suggested by Ellison et al. disturbance or modification. The goal of 2005 [11], transects in wilderness areas were this survey is to provide a comparison of carried out along established trails both to the foraging habits of Grand Cayman’s promote ease of travel in the dark and also insectivorous bat species in relation to to improve repeatability of results. landscape changes caused by humans. The survey conducted attempts to examine Partially Modified areas exhibited a near two hypotheses: firstly, the bats species of even blend of anthropogenic structures and

9 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler natural habitat. Middle density subdi- The Anabat System Practical Guide, in visions with larger yards and accordance with various other surveys, neighborhoods tucked into farmland or suggests implementing walking transects at swampland were commonly placed in this dusk or dawn to coincide with maximum category. The presence of vacant lots levels of bat activity [11, 13 & 14]. Each survey featuring secondary growth or nearby began 0.5 hours after sunset, and continued pastures was a key characteristic for for two hours. Each transect was completed placing areas in this category. Areas of eight times, or once every fifteen minutes. human infrastructure and natural or When possible, the bat detector was pointed secondary growth each constituted 40-60% toward bats in order to generate clearer of Partially Modified areas. results [23 & 14]. Since bats don’t fly in moderate to heavy rain [11-13], the survey Urban areas were characterized by was paused in instances of inclement extensive or total modification and high weather, and resumed when the rain ended. human population density. Crowded The time involved was not counted against suburbs, commercial areas, and industrial the two hour time limit. A flashlight was parks were placed in this category, along used when necessary, and when possible it with areas that were cleared and filled but was covered by a red filter to limit the not subsequently planted or landscaped. amount of light disturbance to bats [13]. Urban areas contained 10% or less unmodified or natural habitat. Recordings were downloaded to a laptop computer with AnalookW 3.3 software Studies indicate that employing tape (Titley Scientific, Queensland, Australia). recorders for acoustic monitoring led to AnalookW exhibited the echolocation greater distortion and degradation than recordings as plots of frequency against computerized monitoring, which produced time. Bat calls were identified at the higher-quality recordings [11 & 12]. As such, species level by comparing the echolocation an Anabat SD1 CF Bat Detector (Titley patterns in the plots produced throughout Scientific, Queensland, Australia) was the survey to previously identified species utilized to record echolocation calls. This in plots provided by George Marks (Florida device saved data directly to a Bat Conservancy, Florida, USA) [15] and CompactFlash (CF) memory card. The bat Richard K. LaVal (The Bat Jungle, detector’s sensitivity level was set to 6 per Monteverde, ) [16]. The specific Ellison et al. (2005) [11], and the division characteristics used to identify each species ratio was set to 16. The calibration button included the shape inherent in the was pressed every fifteen minutes, at the echolocation patterns of each, and their start of each transect. Batteries were typical frequencies; especially the replaced once weekly on a Sunday or when minimum and maximum frequencies. Since the low battery light was lit, whichever this study focuses on the feeding patterns of occurred sooner. insectivorous bats, search phase echolocat-

10 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler

ion calls were used only to identify the A multivariate analysis of variance recorded species. Once identified, the (MANOVA) was used to examine the number of feeding buzzes emitted by each total number of feeding buzzes recorded, species were counted. For the purpose of as well as the number of species data analyses, feeding buzzes were defined recorded, and their relationship to habitat as the rapid, patternless phase of a call type and covariates such as temperature, typically denoting the consumption of an cloud cover, wind speed, and moon phase insect subsequent to the attack and search (retrieved daily from the Cayman Islands phases of the call. Government website, www.gov.ky). The model was simplified by backward Statistical Analyses removal of non-significant effects. For Statistical tests were carried out in SPSS the purposes of this analysis P-values of 15.0 (SPSS Inc., Illinois, USA) and less than 0.05 were considered checked utilizing R 2.9 (www.r- significant. project.org). Using SPSS, the data was checked for distribution normality (one- sample Kolmogorov-Smirnov test), and Results variance homogeneity (Levene’s test). During this survey calls and feeding Tests indicated that in fact the data had buzzes were identified for 5 species: M. neither a normal distribution nor a molossus tropidorrhynchus, L. borealis, homogenous variance, but transformation E. fuscus minor, T. brasiliensis muscala (log10) improved fit to model assumption and A. jamaicensis parvipes. The vast and all residuals were normal. majority of calls belonged to M. molossus

Figure 2. Total number of feeding buzzes recorded in each of the three habitat types surveyed.

11 Flicker (2010) 6, 7-17

7 7-1 6, 2010) ( cker i Fl 12 h Figure 3. a

b Proportion % Proportion % itats; (c) in P roporti on % P roporti on % 00 20 400 6600 8800 100 100 0 2200 4060 6080 800 110000 M M M M . . . . T m m m m (a) (c) h M M M M M M M M o o o o e l l l l ......

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Proportion % Proportion % Proportion % Proportion % 00 20 400 6600 8800 100 100 00 200 44060 6080 800 1 1000 M M M M (b) (d) . . . . m m m m e M M M M M M M M o o o o d (a ...... l l l l m m m m m m m m o o o o s s s s o o o o o o o o s s s s l l l l l l l l ) overt o o o o o o o o u u u u s s s s s s s s s s s s s s s s s s s s u u u u u u u u s s s s s s s s E E E E . . . . f f f f h E E E E u E E E E u u u e durat s s s . . . . s . . . . f f f f f f f f c c c c u u u u u u u u u u u u s s s s s s s s s s s s c c c c c c c c u u u u u u u u s s s s s s s s i o T T T T n . . . . T T T T T T T T bras bras bras bras of t ...... br br br br br br br br as as as as as as as as i i i h i l l l l i i i i e sur ens il il ens il il ens il il il il ens ie ie ie ie ie ie ie ie ns ns ns ns ns ns ns ns i i i i s s s s is is is is is is is is v ey L. L. L. L. L. L. L. L. L. L. L. L. ; (b)i boreal boreal boreal boreal b b b b b b b b o o o o o o o o r r r r r r r r e e e e e e e e a a a a a a a a n l l l l l l l l i i i i i i i i s s s s s s s s

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tler Wa . P – tion modifica t a it hab d an ng i rag o f t Ba Bat foraging and habitat modification – P. Watler

Figure 4. Total number of bat species identified in each of the three habitat types surveyed.

tropidorrhynchus (84%). The total number 0.732, F = 6.6574,158, p< 0.001; Figs 2-4). of feeding buzzes recorded for L. borealis Increasing the level of habitat and E. fuscus minor also decreased modification resulted in decreased significantly in response to increasing foraging activity, with numbers of feeding habitat modification. L. borealis was not buzzes recorded focused in landscape with recorded foraging at all outside near less habitat modification (Figs 2 & 3). natural habitat types, while E. fuscus Additionally results indicated that some minor was only rarely recorded feeding in species of Grand Cayman’s bats actively partially modified habitat types and never avoid developed areas, with significantly in urban habitat. No effect of habitat type fewer species identified in more developed on foraging behavior was observed for T. habitats (Fig. 4). As such, the hypothesis brasiliensis muscala. Only one feeding that as habitat modification increases, both buzz was recorded for A. jamaicensis the total number of feeding buzzes parvipes, this was in near natural habitat, recorded and the total number of species and Macrotus waterhousii minor was not recorded foraging decrease is accepted. recorded at all during the course of this Separate univariate ANOVAs agree that survey. habitat has a significant effect on the total number of feeding buzzes recorded and The MANOVA revealed a significant the total number of species recorded multivariate relationship between the total foraging. number of feeding buzzes recorded the total number of species recorded foraging A Kruskal-Wallis test indicated a sign- and habitat types (MANOVA; Wilks’ λ = ificant effect of habitat type on species

13 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler

richness (Kruskal-Wallis; χ2 = 13.0812, p habitats. As the most commensal of Grand = 0.001; Fig. 4). Therefore, the hypothesis Cayman’s bat species [10], it seems that as habitat modification increases, reasonable that M. molossus species richness decreases is accepted. tropidorrhynchus feeding buzzes comprise the majority of calls recorded in developed areas, as this species roosts exclusively in Discussion man-made structures on Grand Cayman. It As expected, the major findings of this does however come as a surprise that its study suggest that bat foraging activity in foraging activities appear concentrated in Grand Cayman is focused in natural natural habitats and not equally distributed habitat types. The effect of increasing across all habitat types. This acts as an habitat modification is a reduction in the indication that the remainder of Grand overall foraging activity in the area, Cayman’s bat species, which are not regardless of species. This study also adapted to roost in urban areas, may be indicates that a greater number of Grand severely disadvantaged when competing Cayman’s bat species utilize natural with M. molossus tropidorrhynchus. habitat types for foraging, than modified landscapes. Habitat modification also The foraging activities of T. brasiliensis results in a decrease in relative abundance. muscala, on the other hand, were not at all Although this study did not highlight any significantly affected by habitat type. specific factors affecting foraging Although it has been observed that this behavior the large scale alterations in species only roosts in undisturbed areas on habitat are likely to affect foraging Grand Cayman, these results indicated that patterns through a combination of factors: they are able to successfully perform light level, noise disturbance, prey foraging behaviours in all habitat types. abundance and access to roost and There are no clear indicators of why this is foraging sites. the case.

M. molossus tropidorrhynchus was by far The non-detection of either L. borealis or E. the most commonly recorded species. fuscus minor in any of the urban habitats Though habitat modification resulted in surveyed and the lack of L. borealis in significantly fewer M. molossus partially modified areas was surprising. tropidorrhynchus feeding buzzes being Elsewhere in their range both species have recorded, it was still the bat most often been recorded feeding in urban areas [5, 17 & recorded foraging in partially modified 18]. The rapid rate of development on Grand and urban habitat types. Commensal or Cayman, in conjunction with limited resilient species constitute the majority of availability of undisturbed habitat may have feeding buzzes recorded in developed prevented acclimatization which has the areas, whereas intolerant species are rele- potential to have occurred in locations exhi- gated to near natural or unmodified biting slower rates of development.

14 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler

A. jamaicensis parvipes was also recorded ment of the population to an as yet feeding solely in natural habitattypes; undiscovered location, or caused severe however, the significance is difficult to population decline. quantify as there was only one feeding buzz recorded in the course of the survey. Three other bat species were not recorded Indeed, Band [9 & 19] does not report ever in the course of this survey: Erophylla having recorded A. jamaicensis parvipes sezekorni syops, Phyllops falcatus, and in her acoustic surveys in the Cayman Brachyphylla nana nana. In fact, these Islands, though she has on each occasion same species were missed by Band’s captured this species in nets [9 & 19]. This is previous acoustic surveys [9, 19]. This does likely due to the fact that A. jamaicensis not necessarily reflect a decline in their parvipes is primarily frugivorous, and as population levels however, as LaVal points such does not rely on echolocation in out (2009) [16] that only the species detected precisely the same manner as other bat during this survey were candidates for species found on Grand Cayman. detection using acoustic surveillance techniques. Many sources point out that bat Although it was not recorded during this detectors alone are not sufficient for survey, Macrotus waterhousii minor was accurately investigating habitat use by bats readily detected in Band’s auditory [22, 23]. Certain species that feed primarily surveys up to 2006 [9 & 19] and she found no on vegetable matter were missed in the change in the number of recordings as a course of recording. However, this survey result of Hurricane Ivan [19]. It is possible was specifically designed to focus on the that M. waterhousii minor recordings were feeding activities of insectivorous bats. not made due to their foraging outside the These “loud” bats are easily recorded with hours of the survey, as they are reported to bat detectors, and may be missed by emerge between 30 and 120 minutes after trapping methods [22]. Traps may also catch sunset [20]. Additionally, Band (Bat bats that are not foraging, but flying past to Conservation International, Texas, USA) their preferred foraging habitat. Traps can [21] noted that M. waterhousii minor calls also be difficult to situate in urban areas. wouldn’t be recorded unless acoustic recording equipment was in close To conclude, this study employed bat proximity. As such, the dearth of acoustic detectors to acoustically record the feeding recordings in this survey may not be a buzzes of insectivorous bats, in order to cause for concern. There have been no comparatively assess their foraging activity recent censuses for this species and all across man-modified habitat types. On the known roost sites have been abandoned, island of Grand Cayman, habitat although historic surveys indicated a high modification resulted in a decrease in abundance of M. waterhousii minor in par- foraging activities, as well as a decrease in ticular roost sites. Disturbance of these species richness. Commonly regarded as sites may have resulted in either move- keystone species, bats are vital elements of

15 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler any ecological system and play a pivotal Nicholas Young, Hewitson and Susan Watler, role in maintaining a healthy environment. Kimberly Fellman, Brittany and Mark Mitchell, and As such, mankind has a vested interest in Kristi and Bill Leakey for keeping me company while I walked the transects. I would also like to preserving bat species in every habitat. acknowledge the fine folks that proofread this We owe it to ourselves to ensure that submission, Susan Watler, Thomas Niles, Stuart continued development of Grand Cayman Mailer, Henrietta Kirk, Jonathan Davis, Colin doesn't progress at the expense of these Forster, and especially Siân Rowland. Special useful creatures. Regular monitoring will mention also of my classmates, the finest group of people I have ever had the pleasure of associating ensure that the island's bat populations with. persist at optimum levels.

References Acknowledgements 1. Gaston, K.J., & Spicer, J.I. (2004) This paper was prepared in partial fulfillment of Biodiversity: An Introduction. Oxford: the MSc Conservation and Biodiversity at the Centre for Ecology and Conservation, part of the Blackwell Publishing. School of Biosciences at the University of Exeter 2. Foley, J. et al. (2005) Global in Cornwall. I am incredibly grateful for the assistance of the Overseas Consequences of Land Use. Science, Territories Environment Programme for the 309(5734):570-574. fellowship which covered my tuition and afforded a stipend and bursary. I am also especially grateful 3. Grindal, S.D., & Brigham, R.M. (1998) to the National Trust for the Cayman Islands for an Short-Term Effects of Small-Scale Habitat additional stipend and for assisting with the Disturbance on Activity by Insectivorous importation of equipment. I am grateful also for Bats. The Journal of Wildlife Management, the aide of my parents, Hewitson and Susan 62(3):996-1003. Watler, for subsidizing my living while on Grand Cayman. Special thanks to Dr. Brendan Godley 4. Avila-Flores, R., & Fenton, M.B. (2005). and Dr. David Hosken at the University of Exeter Use of Spatial Features by Foraging in Cornwall for their guidance and direction throughout the course and in the preparation of this Insectivorous Bats in a Large Urban paper. Special thanks also to George Marks of Landscape. Journal of Mammalogy, Florida Bat Conservancy and Dr. Richard LaVal of 86(6):1193-1204. the Bat Jungle for providing me with the diagnostic recordings of bat calls. Thanks to Lois Blumenthal 5. Gehrt, S.D., & Chelsvig, J.E. (2004) of the National Trust for the Cayman Islands for Species-Specific Patterns of Bat Activity in answering my questions and introducing me to an Urban Landscape. Ecological other experts. Thanks also to Dr. Mat DaCosta- Applications, 14(2):625-635. Cottam of the Department of Environment for providing me with the government’s Species 6. Furlonger, C.L., Dewar, H.J., & Fenton, Action Plans concerning bats. I appreciate the M.B. (1987) Habitat Use by Foraging assistance of Allan Ebanks at the Cayman Islands Airport Authority for providing me with Insectivorous Bats. Canadian Journal of meteorological data. I would like to acknowledge Zoology, 65(2):284-288.

16 Flicker (2010) 6, 7-17 Bat foraging and habitat modification – P. Watler

7. Longcore, T., & Rich, C. (2004) Common Field Problems and Problem Ecological Light Pollution. Frontiers in Solving. Queensland: Department of Ecology and the Environment, 2(4):191- Natural Resources. 198. 14. Churchill, S. (1998) Australian Bats. 8. Stone, E.L., Jones, G., & Harris, S. New Holland: New Holland Publishers, (2009). Street Lighting Disturbs Ltd. Commuting Bats. Current Biology, 15. Marks, G. (2009) Florida Bat 19(13):1123-1127. Conservancy, Florida, USA (personal 9. Band, A. A Comparison of Bat Species communication) Richness and Abundance in Developed and 16. LaVal, R.K. (2009) The Bat Jungle, Undeveloped Habitats on Grand Cayman. Monteverde, Costa Rica (personal (in progress) communication) 10. DaCosta-Cottam, M., Olynik, J., 17. Kurta, A., & Baker, R.H. (1990) Blumenthal, J., Godbeer, K.D., Gibb, J., Eptesicus fuscus. Mammalian Species, Bothwell, J., Burton, F.J., Bradley, P.E., (356):1-10. Band, A., Austin, T., Bush, P., Johnson, B.J., Hurlston, L., Bishop, L., McCoy, C., 18. Shump, Jr., K.A., and Shump, A.U. Parsons, G., Kirkconnell, J., Halford, S. & (1982) Lasiurus borealis. Mammalian Ebanks-Petrie, G. (2009) A. Cayman Species, (183):1-6. Islands National Biodiversity Action Plan: 19. Band, A. Effects of Hurricane Ivan on Bats: Department of Environment, Cayman Bat Species Richness and Abundance on Islands Government. Grand Cayman. (in progress) 11. Ellison, L.E.,Everette, A.L., & Bogan, 20. Anderson, S. (1969) Macrotus M.A. (2005) Examining Patterns of Bat waterhousii. Mammalian Species, (1):1- Activity in Bandelier National Monument, 4. New Mexico, by Using Walking Point Transects. The Southwestern Naturalist, 21. Band, A. (2009) Bat Conservation 50(2):197-208. International, Texas, USA (personal communication) 12. Johnson, J.B., Menzel, M.A., Edwards, J.W., & Ford, W.M. (2002) A 22. Sherwin, R.E., Gannon, W.L., & Comparison of 2 Acoustical Bat Survey Haymond, S. (2000) The Efficacy of Techniques. Wildlife Society Bulletin, Acoustic Techniques to Infer Differential 30(3):931-936. Use of Habitat by Bats. Acta Chiropterologica, (2):145-153. 13. de Oliveira, M.C., Schulz, M., Hogan, L., & Smith, G.C. (1998) Anabat System 23. O’Farrell, M.J., & Gannon, W.L. Practical Guide: Survey Techniques, (1999) A Comparison of Acoustic Versus Collection and Characterisation of Capture Techniques for the Inventory of Reference Bat Echolocation Calls, Bats. American Society of Mammalogists, 80(1):24-30. 17 Flicker (2010) 6, 7-17 Flicker (2010) 6, 18-22

Essays and Notes

Introduction of captive-bred White-Crowned Pigeons, Patagioenas leucocephala, in to the Wild Via Soft Release Peter Borg Boatswain’s Beach, Grand Cayman, Cayman Islands [email protected]

Background mangroves [6-8]. White-Crowned Pigeon’s The aim of the Boatswain’s Beach (BB) usually breed in mangroves and they have bird release program is multipurpose: to one or two chicks, which both parents help supplement existing White-Crowned to raise [6, 8, 9 & 10]. The parents are able to Pigeon, Patagioenas leucocephala (Fig. fly long distances from their nesting sites 1) populations with captive-reared to their feeding grounds and out of individuals; to help direct focus on breeding season they can form large flocks conservation issues; and to create while foraging for food [6 & 10]. These educational opportunities for institutions pigeons are known to be a migratory such as St. Matthew's University. species that can fly long distances [6]. Consequently, it is difficult to determine Two releases have been conducted to date, how transient this species is on Grand the first in September 2008 with six birds Cayman. and the second in October 2009 with seven birds. The biggest challenge any release program faces is the lack of good quality habitat [1-4]. According to surveys made on Grand Cayman, the habitat at the release site is still good quality but is fragmented [5]. To deem the program a success or a failure, a long-term post- release study needs to be carried out.

White Crowned Pigeon The White-Crowned Pigeon is an Figure 1. Female White-Crowned Pigeon, indigenous species distributed throughout Patagioenas leucocephala. Image: Peter Borg the West Indies, the Central American Caribbean coastline and the southern part The population of White-Crowned of Florida. They normally feed on wild Pigeons on Grand Cayman has drastically berries and fruits of hardwood trees and declined since the mid 1980s [6]. Surveys

18 Release of captive-bred White-Crowned Pigeons – P. Borg made by the Cayman Islands Bird Club in Release site 2004 after Hurricane Ivan estimated that One thing all release programs need to 75-90% of the land bird population had take into consideration is whether the been lost due to the storm [5]. A 2005 original threat has been eliminated from “snap shot” bird count identified only 26 the habitat where the reintroduction will White-Crowned Pigeon on Grand take place [1-4]. Grand Cayman still has Cayman, with 25 of those in the western suitable habitats for the White-Crowned part of the island [4]. This demonstrates Pigeon but these habitats are declining and that the White-Crowned Pigeon population are often fragmented foremost due to on Grand Cayman is doing poorly and that property/land development [5]. the added stress after a big storm similar to Hurricane Ivan can have a devastating The release site is located on BB premises effect. Despite the decline and the (West Bay, Grand Cayman) in an vulnerability of this species, they still ecologically suitable area with appropriate remain on the game bird list in The feeding habitats for the White-Crowned Cayman Islands. Pigeon, even though the area is fragmented [5]. Although the numbers of The White-Crowned Pigeon was selected wild White-Crowned Pigeon in Grand as the release species for two main Cayman are low overall, it is important to reasons: 1) there is still an existing make sure that the reintroduced birds do population, and according to a study by not cause the local population in the Griffith et al. [4] it’s better to augment an release area to exceed the carrying existing population before the density has capacity. Overcrowding a suitable habitat become too low and cannot sustain itself. can lead to aggression and would not 2) White-Crowned Pigeons are a popular benefit the population as a whole [1 & 2]. bird with the locals, which will make it The numbers of birds released by BB are easier to get acceptance for the program low and should not cause any [1]. disturbances. The first year (2008) BB released six birds and seven in 2009. All serious release programs should include strategies for promoting Selecting the birds conservation education [1 & 2]. The BB All release birds were bred in captivity at release program is used as an educational BB free flying aviary. The first White- tool to create and enhance public Crowned Pigeons in BB aviary were awareness for both locals and visiting obtained from local breeders who in turn guests in regards to the negative impact caught the birds from the local wild habitat destruction and other human population on Grand Cayman. This related threats have on the local flora and ensures that the release-pigeons have a fauna. close genetic match with the wild population [1 & 2].

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Flicker (2010) 6, 18-22 Release of captive-bred White-Crowned Pigeons – P. Borg

Disease screening where they were kept separated from the It is important to treat disease as a threat aviary birds and from the wild population. when introducing captive (or wild) The flight cage was large enough (12’ x animals to a resident wild population [1 & 5’x 8’) for the birds to fly, allowing 2]. All BB potential release birds went sufficient exercise. Part of the cage (1/4) through health screening when removed was covered to give shelter from rain and from the aviary. A board-certified avian wind. specialist (Dr. Heather Barron) together with veterinary students from St. The birds were observed twice a day for Matthew's University performed the health clinical signs of illness, injury, abnormal checks. The health screening included behavior and abnormal feces. Mortality blood, fecal and a general physical and all deviations from normal health and examination. behavior were reported to the consulting veterinarian. Any deceased birds were Introduction to flight cage submitted for a necropsy. After the health screening, the birds were moved to an outdoor flight cage (Fig. 2) Food transition To condition the birds for release they were transitioned from regular aviary pellet diet to a natural wild diet (Table 1) found at the release site. The aviary diet was slowly phased out while the natural wild diet was presented in abundance. The time it took to transition the birds varied from a couple of weeks in 2008 to just over a month in 2009.

Table 1. Type of wild food presented. All wild food was collected from plants in the release area Plant Cabbage tree Guapira discolor Red Birch Bursera simaruba Sea Grape Coccoloba uvifera Silver Thatch Coccothrinax proctorii Strawberry Eugenia axillaris

Figure 2. Flight cage strategically situated away The food was presented with the from visiting guests at Boatswain’s Beach. appropriate branches and leaves so that the Image: Peter Borg

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Flicker (2010) 6, 18-22 Release of captive-bred White-Crowned Pigeons – P. Borg birds would be able to identify their food different occasions. This invoked a panic source in the wild after the release. This frenzy among the release birds, which we was part of the food recognition process, took as a confirmation that they could still which is instrumental for the success of identify and have a natural response to the release program [1 & 2]. The birds were predators. held in the flight cage for almost six months in 2009 and 4 months in 2008 until Release procedures there was considered to be enough wild The birds were released via soft-release. food present in the release site for a That means that the flight cage was release. Before the birds were released, opened so the birds could leave and re- they underwent another physical exam and enter at their discretion. Supplemental were reweighed. If a bird had lost more wild diet and water were provided for the than 10% of its body weight, then it was birds inside and outside the flight cage for not released at that point. Of all the release as long as the birds stayed in the release birds, only one lost close to 10% of its area. After both 2008 and 2009 some of body weight (in the 2009 release). The our White-Crowned Pigeons were seen up bird was on a 100% wild diet but it was to 3 weeks after the release. At least two the lowest in the hierarchy and several different birds from the first release other birds prevented it from eating. This showed up at the release site, six months bird had to be released three weeks after later, during the dry season. Food and the others, after it had regained its weight. water was then provided for the birds.

Predator recognition Post release monitoring Captive reared birds may lose the To measure if a release is a success or a appropriate predator avoiding behavior failure, a thorough post release monitoring and therefore it is important to train this program should take place [1, 2 & 4]. To survival skill [1, 2 & 11]. Appropriate make post release monitoring possible, all predator avoidance behavior, is more released birds were ringed with metal likely to persist, in first and second bands during 2009. The bands which are generation birds [11]. To prepare the White- on the left leg are silver and have an Crowned Pigeons for the wild, and to inscription, identifying that it was released ensure they respond appropriately to from Grand Cayman (GCM), Boatswain’s potential threats a few measures were Beach (BB), what year it was released (09) taken: All interaction between the release along with an identification number birds and humans were being kept to a consisting of four digits. To be able to minimum. All birds were first generation make visual confirmation from afar, the born in captivity. To make sure all release right leg was ringed with a colored metal birds shared a flight reaction when seeing band (black, blue, green, purple, red, silver a predator; a raptor (hawk) silhouette was or yellow). introduced over the flight cage on two

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4. Griffith, B., Scott, J.M., Carpenter, J.W. The aspiration is to involve the public to & Reed, C. (1989) Translocation as report sightings of the released birds and a species conservation tool: Status and that way obtain more information, not strategy. Science, 245:477-480. only in regards to their survival and dispersal on Grand Cayman but also to 5. Bradley, P.E. (2005) Cayman Islands learn more about their migratory patterns. Bird Club/National trust. Snap shot Bird Radio tracking the birds would be the Count on Grand Cayman performed by the optimal way to gather that information, bird club in March 2005. (unpublished data) but so far we have not been able to obtain the funds necessary to buy the equipment. 6. Bradley, P.E. (2000), The Birds of the Cayman Islands. British Ornithologists’ For more information or any comments Union, BOU Checklist Series: 19. ISBN regarding BB release program please 0907446 23 X contact: 7. Raffaele, H., Wiley, J., Garido, O., Keith, A. & Raffaele, J. (2003), Birds of the West Peter Borg Indies, Princeton University Press, ISBN 0- ([email protected]) or 691-11319-X Geddes Hislop ([email protected]). 8. Baicich, P.J. & Harrison, C.J.O. (2005) Nests, eggs and Nestlings of North References American Birds, (2nd edition), Princeton 1. IUCN/SSC Guidelines for Re- University Press, ISBN 0-691-12295-4 introductions, Prepared by the SSC Re- introduction Specialist Group Approved 9. Observations done at Boatswains Beach by the 41st Meeting of the IUCN Council, free flying aviary, by aviary staff from Gland Switzerland, May 1995, September 2006 until present. Unpublished. (http://www.iucnsscrsg.org/) All observations are recorded and kept at Boatswains Beach. 2. Guidelines for Reintroduction of Animals Born or Held in Captivity. 10. Sutton, A. (2009) SCSCB White- Adopted by the AZA (Association of Zoos Crowned Pigeon Working Group Meeting. and Aquariums) Board of directors on (unpublished data) June 3, 1992. 11. Griffin, A.S., Blumstein, D.T., & Evans (http://www.aza.org/reintroduction/) C.S. (2000) Training Captive-Bred or 3. Cheyne, S.M. (2006) Wildlife Translocated Animals to Avoid Predators. reintroduction: Considerations of habitat Conservation Biology, 14:1317-1326. quality at the release site. BMC Ecology, 6:5 doi:10.1186/1472-6785-6-5

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