Black-throated Blue Warbler - Status and Threats

Status and Threats

The black-throated blue warbler enjoys a large range and a big population. Its population trend is currently increasing. This species is ranked as Least Concern by the IUCN in 2012. Deforestation and habitat fragmentation are threatening the black-throated blue warblers in their tropical wintering areas. A report in 2000 discussed the impact of global climate change on the population dynamics of the black-throated blue warblers by an observation from 1986 to 1998. In particular, the effect of El Niño Southern Oscillation (ENSO) was studied in relation to the survival, fecundity and recruitment of this migratory bird. It was found that El Niño years (the warm oceanic phase) were associated with lower adult survival rate in their wintering ground, Jamaica, lower fecundity in the breeding habitats in New Hampshire of the United States, and lower annual recruitment of yearlings and juveniles to both breeding and wintering grounds. All the three factors were relatively higher during La Niña years when the weather was wetter and the food availability was much more abundant. The long-term global warming can aggravate the ENSO effect, adding to the fluctuation of the black-throated blue warbler population.