Justification of Red List Category
This species is considered to be undergoing a moderately rapid decline, even though the threats to the species have been difficult to ascertain. Therefore, it has been listed as Near Threatened.
Rosenberg et al. (2016) estimate the population size to be 19,000,000 mature individuals.
Rosenberg et al. (2016) estimated reduction of 60% between 1970 and 2014, roughly equating to a reduction of 25.4% over three generations (14.1 years). Sauer et al. (2017) also suggest that the reduction is not only historical. Conversely, Christmas Bird Count data shows an annual increase between 1966 and 2017 (T. Meehan in litt. 2018), but only a very small proportion of its non-breeding range is within the United States.
Looking at short-term trends, Sauer et al. (2017) present year by year records, and so we can extrapolate trends for any three generation period. Extrapolating trends between 2004 and 2015 to 2018 in order to estimate the population trend over the past three generations shows the population has been, in general, decreasing with a significant, estimated annual decrease of 2.23% (1.21 to 3.40%) (Sauer et al. 2017). This equates to a reduction of 27.2% (15.8-38.6%) over three generations. The Sauer et al. data appears to show that the rate of decline slows after 2006, however, Partners in Flight also gives the species a future half-life of 34 years, which would equate to a decrease of 25.0% over three generations (Rosenberg et al. 2016). Therefore, it is tentatively assumed that declines will continue into the future at the current rate of 20-29% over three generations.
Selasphorus rufus is a migratory hummingbird that breeds in western North America from south-eastern Alaska (U.S.A.) through western Canada and into north-west U.S.A.. In the non-breeding season it migrates to southern California, the Gulf Coast of U.S.A. and across much of Mexico.
During the breeding season this species occurs in a broad range of habitats from secondary succession vegetation and mature forest to parks and residential areas (Healy and Calder 2006). In the non-breeding season it occurs in a variety of habitats, including scrubland, arid thorn forest and mixed pine-oak-juniper forest (Healy and Calder 2006, Powers et al. 2018). It feeds on nectar from several different plant species, as well as on arthropod prey (Powers et al. 2018), and breeding may be timed to coincide with the flowering of food plants (Powers et al. 2018) (recorded from end of March to mid July; Healy and Calder 2006).
In some cases human activity may actually benefit this species. Forest degradation may increase the availability of certain food flowers (see Healy and Calder 2006), and food availability can be artificially increased by the presence of feeders, which can also help increase abundance (Healy and Calder 2006, Powers et al. 2018). However, while the species may tolerate some forest degradation, habitat destruction could impact the species (Rosenberg et al. 2016, Powers et al. 2018), and as this species is typically found in cooler climates, climate change is likely to be a potential threat (Rosenberg et al. 2016). However, the full reasons behind the continued declines are not fully understood.
Conservation Actions Underway
No direct actions are known, but it is placed on the Yellow Watch List by Partners in Flight (Rosenberg et al. 2016).
Conservation Actions Proposed
Conduct targeted research to get better ideas of the population size and trends and the threats to this species. There are also a range of potential ecological questions that may require further research such as more accurately assessing the diet and population dynamics of the species, further investigating the breeding biology of the species, and investigating its ability to colonise new potential habitats (see Healy and Calder 2006).
Text account compilers
Butchart, S., Westrip, J., Ekstrom, J.
BirdLife International (2019) Species factsheet: Selasphorus rufus. Downloaded from http://www.birdlife.org on 18/01/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/01/2019.