The phrase "a bird which" is correct and usable in written English.
It can be used when introducing a clause that provides additional information about a specific bird.
Example: "I saw a bird which was singing beautifully in the tree."
Alternatives: "a bird that" or "a bird who".
Mark Cocker, in his wonderful Birds Britannica, waxes lyrical over a bird which got William Blake's dander up: "A robin redbreast in a cage / puts all Heaven in a rage".
The tube is stolen by a bird, which flies away.
A mosquito becomes infected by biting a bird which carries the virus.
On the way, his jet had hit a bird, which knocked out the radar.
Or should he follow the Samurai adage that haunted him, "Even a hunter cannot kill a bird which flies to him for refuge"?
Likewise, the plastic flamingo does look generally like a bird, which fishers eat, but not like anything they could find in New York.
The phoenix, an emblem increasingly associated with her during her lifetime, is a mythical bird which enjoys a long life and then miraculously and asexually renews itself from the ashes of its own funeral pyre.
I. The New Testament In Living Color A dream sequence which refers to a red-letter edition of "Crime and Punishment", the Word "Yes", a landlord, & a dark bird which springs out of the ground.
A rogue bird which invaded a peregrine falcon nest where four eggs are being nurtured, apparently threatening to destroy them, has been caught on camera.
Among infested birds, no correlation was found (R = 0.01) between the number of larvae and nymphs on a given bird, which is an indication that most larvae and nymphs were not host-seeking at the same time and place.
More concretely, bird watchers may see a new bird, which reminds them of a prior bird that they have seen.
