Archived 2010-2011 topics: Pohnpei Lorikeet (Trichoglossus rubiginosus): request for information

Link to BirdLife species factsheet for Pohnpei Lorikeet

Pohnpei Lorikeet Trichoglossus rubiginosus is listed as Least Concern on the basis that it does not approach the thresholds for Vulnerable under any of the IUCN criteria.

Although this species has a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence less than 20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (at least a 30% decline over ten years or three generations). The population size has apparently not been estimated with a sufficient degree of certainty, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).

This species was previously thought to be common to abundant, with a total population numbering over 10,000 individuals, and have few if any threats, as it reportedly occupies a wide variety of habitats, including human-altered habitats, and is protected from trapping and export as it is the official state bird of Pohnpei (Juniper and Parr 1998). Despite these protections, the species has a history of being traded and shot, and the presence of some birds in captivity suggests that nest poaching is taking place (J. Gilardi in litt. 2010). Another population estimate put the number as low as 50 individuals at one point, with one source estimating the present population at fewer than 500 birds, although this is controversial (J. Gilardi in litt. 2010). Recent observations suggest that the species is fairly common around habitations (per J. Gilardi in litt. 2010).

Although the species is known to use a range of habitats, it may have suffered some effects from deforestation, which has been rapid, with the area of intact native forest being reduced from 15,008 ha (42% of the island’s land area) to 5,169 ha (15%) between 1975 and 1995 (Raynor 1998).

With these inconsistent population estimates and possible threats in mind, up-to-date information is requested on this species, in particular the likely population size, the population trend over 17 years (estimate of three generations) and the severity of potential threats.

Juniper, T. and Parr, M. (1998) Parrots: a guide to the parrots of the world. Robertsbridge, UK: Pica Press.

Raynor, B. (1998) The Pohnpei Community Natural Resource Management Program. Case study for the Sustainable Rural Development Information System: http://srdis.ciesin.org/cases/micronesia-001.html. Accessed 22 November 2010.

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5 Responses to Archived 2010-2011 topics: Pohnpei Lorikeet (Trichoglossus rubiginosus): request for information

  1. I have two concerns here regarding the background information above, one having to do with range and habitat, and the other having to do with historic numbers.

    The entire island of Pohnpei is about 345 km2 in size which is less than 2% of the 20,000 km2 threshold for Vulnerable. Given the loss of forest cover mentioned above in the Reynor report, it sounds as though over the past 17 years there has also been a substantial loss of forest habitat on the island.

    The second issue is the 10,000 individuals figure. My guess is that this ‘estimate’ came from a meeting in which this same number was assigned to a large number of parrots, particularly those where almost nothing was known about their actual abundance in the wild. If there is a real source for this figure – ideally direct observation – then of course it should be retained as a useful historic benchmark, if not, then it is misleading and perhaps should be omitted from this background information.

  2. Andy Symes says:

    John R Gilardi has kindly provided the following information:

    I visited Pohnpei for approximately four weeks during December 2008/ January 2009. I was living aboard a sailboat but made frequent trips ashore for supplies. On my first visit, I saw 15 – 20 Pohnpei Lorikeets on my walk into town, mostly flying over in pairs or foursomes, vocalizing. I rarely got a good look at them through binoculars as they were usually moving high and fast. I visited the offices of The Nature Conservancy and the Conservation Society Pohnpei to see if there was anyone there who knew about the birds or was working on their conservation. I was told that their numbers had declined in the 1980’s to 30-40 birds total, due to habitat loss, forest clearing for growing kava/sakau (Piper methysticum), shooting to eat and possibly capture as pets (now illegal). It sounds as if they got people to stop shooting the lorikeet, worked with the kava growers to stop clearing forest, etc. Now, according to the guy at CSP there are 300-400 birds total, but based on how frequently I saw them around town, I would guess that is a conservative estimate.

    Each time I visited the island, I saw dozens of lories, typically flying fast, well overhead, and I also heard them frequently. Once, I stopped at a house to observe a caged lorie; it was very playful, taken from the nest by a friend of the owners from far away; the owner, a “senator” gave me a ride to a restaurant a mile out of town that had another captive bird, just as cute and curious.

    Bill Raynor of The Nature Conservancy initiated a conservation effort for the lorikeet in past years. According to Raynor, the Lorikeet had two strikes against because they were considered an agricultural pest and, according to tradition, spied on people, and were somehow in cahoots with evil rulers. So they turned it into the State bird (of Pohnpei, as a state of the Federated States of Micronesia) and changed public perception. Apparently, not much is known about its ecology. I asked many locals, but none knew of a nest site.

    One older man that I spoke with said that when he was younger large flocks were commonly seen (I would guess 30-50-100+ birds) but flocks like this are no longer seen.

  3. Mark O'Brien says:

    I visited Pohnpei in late November/early December 2010.
    I stayed in Kolonia for a few days, where I saw flocks of up to 8 birds regularly while walking around town.
    I watched 12 birds fly to the peninsula opposite the CSP offices at dusk on the 27th November. I also watched 2 birds fly from the peninsula back to Kolonia!
    I walked to Dolen Kahmar (a distance of c8km) on 2 occasions, on the afternoon of 26th and morning of 27th November. The walk was through agricultural land with buildings and wooded ‘gardens’. I estimated a minimum of 20 and 35 Lorikeets on the two walks.
    I spent 7 nights camping in the Watershed Forest Reserve and surveyed at sites >550m asl. I conducted 48 point counts during this time recording 54 registrations of 74 individual birds. Point counts arent good ways of surveying lorikeets as the majority of registrations were of birds flying past. The point counts were 8 minutes in extent, I made no attempt to estimate distance of birds at a single given time.
    So, Pohnpei Lorikeet was one of the commonest birds on the island, being present in all habitats that I surveyed. I didn’t see large flocks of birds in any of the habitats that I surveyed. I saw one, disshevelled bird in a cage in a restaurant near Kolonia. My colleagues from CSP made no mention of Lorikeets as being an agricultural pest – although I didn’t ask them that question.
    I don’t recognise the picture of large areas of forest lost to agriculture, although I may be biassed by my focus on forested areas in the high ground. CSP have offered to attempt to estimate the extent of forest based on recent aerial photographs – they currently have a project that maps all areas of forest that have been felled to make way for Kava crops – a continuation of the grow low campaign.
    In any case I don’t see loss of forest per se as being a substantial issue for Lorikeets on Pohnpei. They seem able to cope with dispersed trees in a more modified environment hence the numbers in Kolonia. There are species on Pohnpei for which the forest extent will be important – this currently isn’t one of them. The idea that the birds declined to c50 individuals is, currently, difficult to believe. I do note that the Lorikeet was one of the four most commonly recorded species in the point counts surveys in 1983 and 1994 – the earlier survey being well before the conservation measures put in place as mentioned above. So the suggestion that the population had declined to c50 in the 1980s and then bounced back in 1994 seems somewhat fanciful.

  4. Mark O'Brien says:

    An alternative viewpoint might be to consider the 2 surveys undertaken in 1983 and 1994. If one compares mean encounter per hour between those surveys then there is a 74% decline in encounter rate in Pohnpei Lorikeet over that time period (Buden 2000*). Similar reductions in encounter rates were recorded for many other species in Pohnpei. Note that Buden (2000) does state that comparisons are not necessarily based on like v like, but that there was evidence that bird populations in Pohnpei had declined since the early 1980s. Buden recommends increased frequency of monitoring. Another survey would appear to be appropriate.

    If one takes the point counts that I undertook last December and estimates encounter rate per hour then there is a further 30% decline compared with 1994. This is even more dubious a comparison – because 1983 and 1994 surveys were undertaken at a different time of year – May.

    There does seem to be little evidence that the population had crashed by the 1980s. However, the evidence does suggests that there has been a decline since the 1980s which may still be occurring up to the current time.

    *Buden DW. 2000. A COMPARISON OF 1983 AND 1994 BIRD SURVEYS OF POHNPEI, FEDERATED STATES OF MICRONESIA. The Wilson Bulletin 112(3):403-410.

  5. Mark O'Brien says:

    Many thanks to Don Buden for providing further information on the 1983 survey co-ordinated and written up by Engbring (1990)*. In total 3,514 Pohnpei Lorikeets were recorded in that survey, from which an AVERAGE density for Pohnpei was calculated as 275 birds per square kilometre. Engbring estimated the total population at 88,107 individuals.
    As mentioned above, I think point counts aren’t a good way of estimating population densities of lorikeets, due to the majority of registrations being flyby records. Accordingly I would imagine that the density is somewhat on the high side. However, I would have thought it unlikely that it was 10 times too high. I would guess from this that a population estimate in excess of 10,000 individuals would not be unreasonable. The apparent decline in numbers as recorded by encounter rates in 1994 and last autumn would suggest that a further survey of Pohnpei Lorikeet and other species on Pohnpei would be a high priority.

    *Engbring,J. FL RAMSEY & VJ WILDMAN. 1990. Micronesian forest bird surveys, the federated states: Pohnpei, Kosrae, Chuuk, and Yap. U.S.
    Fish and Wildlife Service, Department of the Interior, Washington, D.C.

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