Again...from the"evidence," and I appreciate your consideration, bird beaks growing smaller or larger or things like that...they still remain...birds.
Of course, they remained birds.
But birds are not species, YoursTrue. Birds, or it biological taxon name is
class Aves.
There are whole lot of subclasses, orders, suborders, families, subfamilies, genera, species, subspecies, clades, and so on. Birds or Aves are just umbrella name of some shared but very general physical traits.
Saying that every birds having beaks or wings or feathers, “are still birds”, just demonstrates your illiteracy in biology, your incompetency of not learning more about the vast diversity of species.
While falcons and eagles are both birds of prey, they don’t belong into the same order, so their respective families, genera and species differed.
But even the name “falcon” and “eagle”, are not names of their species, they are names of their respective genera, so:
- genus Falco (falcon) include all different species and subspecies of the Falco, so the species Falco tinnunculus, otherwise known as “common kestrel”, the species Falco peregrinus or “peregrine falcon”, and species Falco rusticolus or “gyrfalcon”, are 3 different species of falcons or of the genus Falco. With the kestrels, there are many different species for the kestrels.
- genus Aquila, a Latin name eagle, and like the genus Falco, there are many different species of eagles. Examples, Aquila audax or “wedge-tailed eagle”, Aquila chrysaetos or “golden eagle”, are 3 different species of the genus Aquila (eagle).
You are ignoring that their order or family or genus, these taxons are not species.
No one is saying they are not birds, as birds doesn’t tell us much about the different orders, families & species. Biologists are very specifics in details, while you are being ignorantly general.
The questions to you -
Do the peregrine falcons (Falco peregrinus) belong to the same species as the common ostriches (species Struthio camelus)?
How do they differ, anatomically or morphologically, physiologically?