Range map update
Based on new information submitted in June 2023 the range map has been updated as follows:
Palila (Loxioides bailleui)
Palila (Loxioides bailleui)
Range map update
Based on new information submitted in June 2023 the range map has been updated as follows:
Preliminary proposal
Based on available information, our preliminary proposal for the 2023 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 12 February 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Recommended categorisations to be put forward to IUCN
Following correspondence from Chris Farmer (in litt.) the decision has been made to pend all Hawaii species to the next Forum window (29th May – 2nd July 2023), to allow more time for external input. We still intend to make the submission to the IUCN for the 2023 update but in the interim encourage all those with data that may impact the assessments as written to get in contact with us (redlistteam@birdlife.org).
Many thanks for everyone who contributed to the 2023.1 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I checked the criteria, rational and justification against the most recent population estimates and agree with changing the species’ status to the proposed category. The extent of Native Resident on the range map does not however reflect the species current range which is restricted to the 64 square kilometer core survey area on the southern and southwest flank of Mauna Kea. No birds were detected outside the core survey area in 2020 or 2021 (Genz et al. 2022), and it is unlikely the species persists on the eastern and northern slopes. The species occupies the southeastern slope during summer and autumn months.
I do not agree with the proposed rational for changing status. Palila still meet the the criteria for critically endangered via criterion B (occupy less than 100km2) and via: a. existing only in a single location, and b (i, v). continuing decline of area of occupancy and of mature individuals. From 1998-2011 the area derived from 100% of Palila detections from annual point counts equates to 53.5km2, with more than 50% of detections over the same time interval occurring in an area of only 19.96km2. From 2019-2021, 100% of Palila detections occurred in an area of only 23.15km2. This decline in range also appears to be accelerating, as places where palila were regularly detected in 2019, are now only frequented by the birds on rare occasions or have not been seen at all since 2021.
While there has not yet been a quantitative analysis to assess extinction risk, based on the rates of decline and population estimate reported by Gentz et al 2022, the continued decline in palila detections during annual/quarterly surveys, and the persistence of threats, the species has a high likelihood of extinction in the next decade. A strong argument could be made that Palila, given the available data, also meet criterion E.
Mahalo for this opportunity to provide additional information and for your thoughtful consideration.
Although palila do not quite fit the abundance and range criteria for classification as Critically Endangered, there are other factors that argue for retaining that status. These have mostly to do with the species’ extreme feeding specialization and its occupation of habitat that represents only part of the diversity found within its historical and pre-contact ranges.
Feeding specialization. Because of their dependence on the unripened seeds of the māmane tree, palila survival and reproduction are tightly linked to the availability of this food and to the insects associated with māmane. Māmane flower and seed production are strongly affected by rainfall patterns, and the prolonged drought from 2000 to 2011 resulted in poor seed crops, which drove the palila population to the very low levels we have observed since then (Banko et al. 2013). That the population has not rebounded since conditions have become more favorable is likely due to the palila’s very slow rate of reproduction (Banko et al. 2020), which is a common feature of Hawaii’s specialist species (Banko and Banko 2009a) and contributing to their historical decline (Banko and Banko 2009b). Now that the El Niño/Southern Oscillation phenomenon has again begun (https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml), we can expect drying conditions in the subalpine habitat of the palila, with attendant poor breeding (Lindsey et al. 1997). Should drought conditions persist for multiple years, the palila population will likely decline further, as it did before.
Habitat. With a range extending from coastal forests on Kauaʻi and Oʻahu islands in pre-contact times to the montane and subalpine forests of Hawaiʻi Island in historic times, palila now occupy the best, albeit highly degraded, habitat remaining to them. Subalpine Mauna Kea is dominated by two endemic trees, māmane and naio, although the extent, density, and diversity of their habitat was greater historically. As is the case for most Hawaiian forest birds, the palila has been stranded in habitat that may be suboptimal.
Despite the low diversity of trees, the vegetation of the subalpine is highly dynamic due to waves of invasions of weeds, diseases, and pests. Although populations of sheep (feral sheep x mouflon sheep) have been reduced in the past decade, the māmane forest is slow to recover and young māmane requires about 25 years of growth before palila frequent them for foraging and nesting. The rate of forest recovery is also slowed by drought and impacts from other threats, including dense introduced grass and weed cover and a non-native fungus (Armillaria mellea), which may account for many dead and dying trees observed today (Banko et al. 2014). Although māmane is critical to the palila’s survival, naio fruit is an important alternative resource when māmane flowers and seeds are scarce (Hess et al. 2014). Since 2010, naio has been heavily affected by an introduced species of thrips (Klambothrips myopori; Banko et al. 2014), and the accumulation of dead wood and heavy grass and weed cover and the trend of lower rainfall increase the threat of wildfire (Thaxton and Jacobi 2009). Wildfire in the small and shrinking range of palila on Mauna Kea (also see comment by R. Camp) poses a grave danger to the short and long-term survival of palila.
Abundance Estimation. As pointed out in the comment by R. Camp, abundance estimates do not meet the criteria for listing palila as Critically Endangered. Nevertheless, point estimates without confidence intervals can be a tenuous guide for evaluating population abundance. Moreover, the population has likely declined based on the low rate of detections during quarterly surveys since 2021. Given that no threatened Hawaiian forest birds have been recovered or are showing promising signs of recovery, it seems premature to downlist the palila’s status when the population is declining and facing major threats to it habitat.
Banko, P. C., and W. E. Banko. 2009a. Evolution and ecology of food exploitation. Pages 159-193 in Conservation biology of Hawaiian forest birds: Implications for island avifauna (T. K. Pratt, C. T. Atkinson, P. C. Banko, J. D. Jacobi, B. L. Woodworth, eds.). Yale University Press, New Haven, CT.
Banko, W. E., and P. C. Banko. 2009b. Historic extinction and decline. Pages 25-58 in Conservation biology of Hawaiian forest birds: Implications for island avifauna (T. K. Pratt, C. T. Atkinson, P. C. Banko, J. D. Jacobi, B. L. Woodworth, eds.). Yale University Press, New Haven, CT.
Banko, P. C., R. J. Camp, C. Farmer, K. W. Brinck, D. L. Leonard, and R. M. Stephens. 2013. Response of palila and other subalpine Hawaiian forest bird species to prolonged drought and habitat degradation by feral ungulates. Biological Conservation 157:70−77.
Banko, P. C., S. C. Hess, P. G. Scowcroft, C. Farmer, J. D. Jacobi, R. M. Stephens, R. J. Camp, D. L. Leonard Jr., K. W. Brinck, J. O. Juvik, and S. P. Juvik. 2014. Evaluating the long-term management of introduced ungulates to protect the palila, an endangered bird, and its critical habitat in subalpine forest of Mauna Kea, Hawaiʻi. Arctic, Antarctic, and Alpine Research 46(4):871−889.
Banko, P. C., L. Johnson, G. D. Lindsey, S. G. Fancy, T. K. Pratt, J. D. Jacobi, and W. E. Banko (2020). Palila (Loxioides bailleui), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.palila.01
Hess, S. C., P. C. Banko, L. J. Miller, and L. P. Laniawe. 2014. Habitat and food preferences of the endangered palila (Loxioides bailleui) on Mauna Kea, Hawaiʻi. Wilson Journal of Ornithology 126:728-738.
Lindsey, G. D., T. K. Pratt, M. H. Reynolds, J. D. Jacobi. 1997. Response of six species of Hawaiian forest birds to a 1991-1992 El Nino drought. Wilson Bulletin 109:339−343.
Thaxton, J. M., and J. D. Jacobi. 2009. Assessment of fuels .potential fire behavior, and management options in subalpine vegetation on Mauna Kea Volcano, Hawaiʻi. Technical Report HCSU013. Hawaʻii Cooperative Studies Unit, University of Hawaiʻi at Hilo, Hilo, HI.
I disagree with the proposed downlisting of Palila to Endangered. I think the data and observations support maintaining it as Critically Rare.
The species has undergone an 89% decline from 1998-2021 (Genz et al 2022). However, since the last formal population analysis in 2021, the population has likely declined further based on low detections in the 2022 and 2023 annual surveys. This qualifies Palila for Critically Rare as A1b – continued decline of a population index for the taxon.
Palila should also qualify as Critically Rare based on its Extent of Occurrence (EOO). The core habitat of Palila of 64.4 km2 was defined to contain 95% of the breeding Palila when we first drew it in 2008 (Leonard et al. 2008). As shown in Genz et al. (2022) the birds are no longer found in a large section of this area. The absence of detections in large sections of this area has continued in the annual surveys since then (2022-2023), and is also shown in recent quarterly surveys tracking the species’ movement on the southwestern slope of Mauna Kea. Currently the species is limited to one, small (<64.4 km2) area, in a dry forest that is highly susceptible to fire. Therefore, Palila are Critically Rare based on criteria B1a,b.
The updated range map is still incorrect. Palila are only found in a small fragment of the green polygon on the southwestern slope of Mauna Kea.
Lastly, Palila qualify as Critically Rare based on its probability to extinction, criteria E. The species has declined at an average of 229 birds/year from 1998-2021, so at this rate from its 2021 point estimate of 678 this would be extinct in less than 3 years. As Genz et al. (2022) show, the rate of population decline has decreased recently, so the projection is not this extreme – but the decrease in detections during annual surveys the last two years suggest the population decline continues. Therefore, the probability of extinction likely exceeds 50% in the next 10 years. Additionally, there is also the threat of avian malaria transmitted by non-native mosquitoes. Currently, this is not an active issue in subalpine Mauna Kea ¬ but Palila are highly sensitive to this disease. Humans are far exceeding climate change projections, and mosquitoes are rapidly moving up the mountains across the Hawaiian Islands, driving multiple honeycreeper species towards extinction, so this factor is likely to occur within the next 10 years.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 26 June 2023. We will now analyse and interpret the new information, and we will post a preliminary decision on this species’ Red List status on this page on 26 June 2023, when discussions will re-open.
Preliminary proposal
We are grateful for the comments submitted during the initial discussion window, and the range map has been further refined to accurately reflect this species’ restricted distribution on the southwestern slope of Mauna Kea. The EOO, based on a minimum convex polygon around the mapped range, is re-calculated as 53 km2, however this is increased to match the AOO of 80 km2 (maximum value calculated by overlaying a 4 km2 grid over the mapped range) as per IUCN Guidelines. Although the rate of decline within three generations (12.5 years) is not thought to exceed the Criterion A threshold, its current listing as Critically Endangered can be upheld under Criterion B. Based on available information therefore, our preliminary proposal for the 2023 Red List would be to list Palila as Critically Endangered under Criterion B1ab(iii,v).
There is now a period for further comments until the final deadline on 2 July 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and we will post a final decision on this species’ Red List status on this page on 10 July 2023.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Palila is recommended to be listed as Critically Endangered under Criterion B1ab(iii,v).
Many thanks for everyone who contributed to the 2023.2 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.