How many birds are there in the world?
About 10 years ago, two scientists decided to estimate the total number of birds on the planet. The number they came up with was 200 to 400 billion individual birds.
I think that this is one of the loveliest birds of Hong Kong. 普通翠鳥 . Common Kingfisher . Alcedo atthis -
That is a lot of birds....BUT... bird numbers have been declining both in terms of species numbers (by about 500 species) and numbers of individuals (by about 20-25%). This decline is due to human activities, such as the cutting down of forests, contamination, invasive species (like cats) , and climate change.