Green-crowned Woodnymph (Thalurania fannyi) is being split: list T. hypochlora as Near Threatened?

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2013 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

Green-crowned Woodnymph Thalurania fannyi is being split into T. fannyi and T. hypochlora, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, T. fannyi (BirdLife species factsheet) was listed as Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. This species was estimated to have a very large range, and hence did not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence [EOO] of 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 is not known, but the population was not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (at least a 30% decline over ten years or three generations). The population size has not been quantified, but it was 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).

T. fannyi (as defined following the taxonomic change) occurs in eastern Panama through western Colombia to north-western Ecuador (del Hoyo et al. 1999). The global population size has not been quantified, but it is described as abundant in Colombia and uncommon to locally fairly common in Ecuador (Ridgely and Greenfield 2001, Restall et al. 2006,). It is able to use disturbed or fragmented forest in many areas, inhabiting humid forest and adjacent edges, tall secondary growth and semi-open habitats (coffee and cacao plantations, overgrown clearings, woody parks, shaded gardens), avoiding open, scrubby areas, to 1,200 m on the Pacific slope and 800-1,900 m on the slopes of Cauca Valley in Colombia (del Hoyo et al. 1999, Restall et al. 2006). The species is thought to warrant listing as Least Concern on the basis that it is no thought to approach the thresholds for Vulnerable under any of the IUCN criteria.

T. hypochlora occurs in the Pacific lowlands of Ecuador from north-eastern Guayas and south-western Chimborazo south through El Oro to western Loja and extreme north-western Peru (del Hoyo et al. 1999, Ridgely and Greenfield 2001). It is described as uncommon in humid forest, up to 950 m in Tumbes, Peru (Schulenberg et al. 2007), and uncommon to locally fairly common in the lower growth of humid forest, secondary woodland and adjacent clearings in the lowlands and foothills, up to c.1,100 m in Ecuador (Ridgely and Greenfield 2001). Overall numbers of T. hypochlora have doubtless declined substantially as a result of deforestation, particularly in the west Ecuadorian lowlands (del Hoyo et al. 1999, Restall et al. 2006), but it remains reasonably numerous at Manta Real in north-west Azuay and Buenaventura in El Oro, although both are areas where a significant amount of forest destruction has taken place (Ridgely and Greenfield 2001).

T. hypochlora could qualify as Near Threatened under criterion B1ab(i,iii,v), if its habitats are considered to be very fragmented (approaching 50% in patches too small to support viable populations), as its EOO is estimated at c.19,600 km², in which suitable habitat is in decline, and the population is consequently inferred to be in decline.

Comments are invited on these suggested categories and further information is requested.

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World, vol. 2: New World Vultures to Guineafowl. Barcelona, Spain: Lynx Edicions.

Restall, R., Rodner, C. and Lentino, M. (2006) Birds of northern South America: an identification guide. Volume 1: species accounts. London, UK: Christopher Helm.

Ridgely, R. S. and Greenfield, P. J. (2001) The birds of Ecuador: status, distribution and taxonomy. Ithaca, NY and London, UK: Cornell University Press and Christopher Helm.

Schulenberg, T. S., Stotz, D. F., Lane, D. F., O’Neill, J. P. and Parker III, T. A. (2007) Birds of Peru. Princeton, NJ: Princeton University Press.

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3. Archived 2011-2012 topics: Neblina Metaltail (Metallura odomae): request for information
4. Archived 2010-2011 topics: Noble Snipe (Gallinago nobilis): is this species declining?
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