BirdLife species factsheet for Foothill Elaenia
The recently discovered Foothill Elaenia (Myiopagis olallai) occurs in a severely fragmented range in the northern Andes. The species is restricted to a few, disjunct localities of occurrence in the Central Cordillera in Colombia, the Sierra de Perijá, the eastern slopes of the Andes in Colombia and Ecuador (Napo, Sucumbíos, Pastaza and Zamora-Chinchipe), as well as in southern central Peru (Pasco, Cusco) (Coopmans and Krabbe 2000, Cuervo et al. 2014, Fitzpatrick 2018). Many records and reported sightings of the species remain unconfirmed. The global population size has not been quantified, but the species is described as uncommon in Sucumbíos, Ecuador.
Foothill Elaenia occurs at elevations between 890 and 1500 m. It inhabits the interior and edges of very humid to wet primary submontane forest (Coopmans and Krabbe 2000). There is not much known about the ecological requirements of the species (Fitzpatrick 2018).
The species’s population is suspected to be in decline owing to ongoing habitat loss. On the eastern slope of the Ecuadorian Andes, forest clearance and less intensive habitat destruction and fragmentation may already have resulted in the loss of around half of the forest cover in the species’s range. It is reported that unspecified development projects, which have already received approval, are likely to increase the future rate of forest loss in Ecuador (D. F. Cisneros-Heredia in litt. 2010). Even within protected areas, forests within the species’s altitudinal range are under imminent threat of illegal logging (Fitzpatrick 2018). However, the species’s preferred areas in superwet forest are to date only under moderate risk of logging (Fitzpatrick 2018).
Currently, Foothill Elaenia is listed as Vulnerable under Criterion B1ab(i,ii,iii), indicating a very small Extent of Occurrence (EOO) and declines in habitat availability.
Following IUCN guidelines, the EOO for this species has been re-calculated using a Minimum Convex Polygon, which is “the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence” (IUCN 2001, 2012, Joppa et al. 2016). After re-calculating the EOO for Foothill Elaenia, this species appears to warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.
The initial topic on this analysis can be found here.
Criterion A – The population trend has not been estimated directly. However, Tracewski et al. (2016) measured the forest loss within this species’s range between 2000 and 2012 as c. 80 km2. This roughly equates to a rate of forest loss of 1.6% over three generations (10.8 years) for this species, with the assumption that habitat loss has continued at the same rate to the present day.For a highly forest-depending species like Foothill Elaenia, population changes may be proportional to forest cover change. Even though Foothill Elaenia is restricted to primary forest, it is highly unlikely that the rate of population decline based on habitat loss alone approaches the threshold for Vulnerable. Therefore, Foothill Elaenia may be listed as Least Concern under this criterion.
Criterion B – Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) has been calculated as 1,020,000 km2. This is far too large for listing the species as Vulnerable under Criterion B1. Tracewski et al. (2016) estimated the remaining tree area within the species’s range to be c.4,300 km2. We can tentatively assume that for a highly forest-dependent species like Foothill Elaenia, the area of forested habitat equals the maximum Area of Occupancy (AOO); as such the maximum AOO is close to the threshold for Vulnerable under Criterion B2 (AOO < 2,000 km2). Given that Foothill Elaenia is known from less than ten locations and EOO, AOO and habitat availability are in decline, the species may approach the threshold for listing as threatened. As such, Foothill Elaenia may be listed as Near Threatened under Criterion B2ab(i,ii,iii), although in fact the maximum AOO may be too large even for this.
Criterion C – The population size of this species has not been estimated. Therefore, it cannot be assessed against this criterion.
Criterion D – The population size of this species has not been estimated. Therefore, it cannot be assessed against this criterion.
Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.
Therefore, it is possible that Foothill Elaenia (Myiopagis olallai) could be listed precautionarily as Near Threatened under Criterion B2ab(i,ii,iii), although the maximum AOO value available may even be too large for this. Further information regarding the population size of this species is needed to get a clearer assessment of its extinction risk. We welcome any comments on this proposed listing and specifically request up-to-date information on the population size of Foothill Elaenia.
Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic.
An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.
Coopmans, P.; Krabbe, N. 2000. A new species of Flycatcher (Tyrannidae: Myiopagis) from eastern Ecuador and eastern Peru. Wilson Bulletin 112: 305-443.
Cuervo, A.M.; Stiles, F.G.; Lentino, M.; Brumfield, R.T.; Derryberry, E.P. 2014. Geographic variation and phylogenetic relationships of Myiopagis olallai (Aves: Passeriformes; Tyrannidae), with the description of two new taxa from the Northern Andes. Zootaxa 3873: 1–24.
Fitzpatrick, J. 2018. Foothill Elaenia (Myiopagis olallai). In: del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D.A.; de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona, Spain. https://www.hbw.com/node/57136 (Accessed 14 September 2018).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria.
Joppa, L.N.; Butchart, S.H.M.; Hoffmann, M.; Bachman, S.P.; Akçakaya, H.R.; Moat, J.F.; Böhm, M.; Holland, R.A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370. Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.