|Scientific Name:||Ptilinopus roseicapilla|
|Species Authority:||(Lesson, 1831)|
|Red List Category & Criteria:||Endangered A3cde; B1ab(iii,v) ver 3.1|
|Contributor(s):||Amidon, F., Hawley, N., Roberts, H., Saunders, A., Holmes, T., Lepson, J. & Wiles, G.|
|Facilitator/Compiler(s):||Benstead, P., Derhé, M., Mahood, S., O'Brien, A., Shutes, S., Stattersfield, A.|
This species qualifies as Endangered because it is restricted to four very small islands, including Saipan, where brown tree snake Boiga irregularis may be in the process of becoming established, and Tinian and Rota where the snake has also been detected. These three islands support 97% of the population. It formerly occurred on Guam, where it was extirpated by brown tree-snake. It is therefore very likely to undergo a rapid overall population decline in the immediate future.
|Range Description:||Ptilinopus roseicapilla is fairly common on four islands in the Northern Mariana Islands (to USA), where it is primarily a bird of mature forest although it is also found in some moderately disturbed mixed woodland and second growth habitats (Engbring et al. 1982, Jenkins 1983, Craig 1996). It has become extirpated from Guam (to USA) owing to predation by the introduced brown tree snake Boiga irregularis, and although single birds turn up once every few years, these are almost certainly individuals dispersing from the island of Rota, 60 km to the north (G. Wiles in litt. 1999). In 1982, the total population was estimated at 9,443 birds, with 2,541 on Saipan, 3,075 on Tinian, 3,535 on Rota and 292 on Aguijan (Engbring et al. 1982). Surveys conducted over the last decade indicate that the species has increased on Aguijan (data from 2008 [Amidon et al. in prep]), declined on Rota (data from 2003 [Amar et al. 2008]) and Tinian (data from 2008, [Camp et al. in press]), and appears stable on Saipan (data from 2007 [Camp et al. 2009]). A recent "Promoting Protection through Pride" campaign on Rota has resulted in legislation fully protecting the species from hunting and trapping (T. Holm in litt. 2000). However, the species must be affected by habitat loss and is at great risk from the recent introduction of B. irregularis to Saipan, and the likely introduction to Tinian.|
Native:Northern Mariana Islands
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population was estimated at 9,443 birds in 1982, consisting of 2,541 on Saipan, 3,075 on Tinian, 3,535 on Rota and 292 on Aguijan. It is placed in the band 2,500-9,999 individuals here, equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.|
|Habitat and Ecology:||This species eats a variety of fruit from the forest canopy (Engbring et al. 1982) particularly from native Ficus spp. and Premna obtusifolia trees. It may also descend to feed in bushes or on the ground, where it takes the fruits of the introduced prostrate vine Momordica charantia (del Hoyo et al. 1997). It is found in a variety of forest types but appears more common in limestone forest (Craig 1996) and to prefer mature native forest (del Hoyo et al. 1997). On Aguijan it is found in heavily grazed forest and on Tinian in the scrubland of introduced Leucaena trees. It seems to breed all year round with a peak in breeding activity and consequently population size during April-July (Craig 1996). It lays one egg in a nest approximately 2.8 m from the ground (del Hoyo et al. 1997).|
Persistent reports from the island of Saipan suggest that the brown tree snake may be in the process of becoming established on the island (Rodd and Savidge 2007), and has also been detected on Tinian and Rota (A. Saunders in litt. 2003, Williams 2004). Although it appears to not yet be established on Tinian and Rota (Amindon in litt. 2007), there is a risk it may be in the future since tourism development on Tinian necessitates the importation of large amounts of building materials (J. Lepson in litt. 1999). Unless the snake can be controlled on Guam and Saipan and prevented from becoming established on Tinian and Rota, the populations on three islands are likely to be extirpated rapidly. Other threats include the spread of introduced plant species, especially Leucaena, habitat destruction and hunting (del Hoyo et al. 1997).
Conservation Actions Underway
A recent "Promoting Protection through Pride" campaign on Rota has resulted in legislation fully protecting the species from hunting and trapping (T. Holm in litt. 2000). A brown tree-snake barrier was constructed at the port on Tinian and plans are underway to build a barrier at the port on Rota to support interdiction efforts (Amindon in litt. 2007, Hawley in litt. 2007). The Mariana fruit dove captive breeding program began in 1993 under the umbrella of the Mariana Archipelago Rescue & Survey (MARS) program and has now evolved into Mariana Avifauna Conservation Program (MAC) (H. Roberts et al. in litt. 2009). Conservation Actions Proposed
Control Boiga irregularis population by trapping and monitor its spread on Saipan. Take precautions to prevent the introduction of B. irregularis onto Tinian and Rota, such as traps and monitoring around the airport and harbour (J. Lepson in litt. 1999). Formulate species management plan, including development of the captive breeding populations, and consider introduction to snake-free islands. Monitor populations on Saipan to assess population trend following introduction of B. irregularis. Control the spread of introduced plant species, especially Leucaena. Implement an education program to help control hunting and limit habitat destruction.
|Citation:||BirdLife International 2013. Ptilinopus roseicapilla. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 07 July 2015.|
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