Are bird populations in tropical and subtropical forests of South America affected by climate change?

The tropical and subtropical moist forests of South America have been seen as remarkable for their great wealth of animals and plants and as the world leader in bird diversity. However, a problem is apparently affecting bird populations in these habitats, to the extent that most of the sites that I have studied in the last few years were practically ornithological deserts. Censuses conducted in the Amazon rainforest in Ecuador and Bolivia have revealed no more than 15 species and 18 individuals in 1 day. It is evident that this is not a problem of the kind usually induced by humans at a local level, such as deforestation, hunting or pesticide use. The low diversity and activity were observed not only in disturbed habitats, but also in well-preserved national parks and reserves. If it is related to human activities, then this must be more widespread. One such possibility is global warming. For ornithological studies, this is a very severe problem that must be closely examined to see whether it is also a threat to bird survival and if it is related to climate change.