How many bird species are in the US?

well its not that we have found the total number of species of birds

they are not yet discovered yet

but from the present research

and after goggling about 150 sites related to the topic

i found out that there are approximately 190000 species of birds

and approx 2,90000 species in total including the prehistoric birds

and if you are asking how many birds are there on earth

then dear it is not yet counted

as the population of birds increase day by day

varying from ten to thousand

so if this is your question is then

there are about 75,56,000 birds

if you think it as a lie

you can count yourself