Is west nile only via mosquito bites, or can you catch it from cleaning up dead birds in your yard or on the street?

Needs a vector: West nile requires a vector (or transmitter). In this case, a mosquito. I am not aware of any evidence suggesting it can be acquired by other means. However, it is wise to use gloves and wash your hands thoroughly when handling any dead animals.

Per CDC:: "Can I get West Nile virus directly from birds? There is no evidence that a person can get infected from handling live or dead infected birds. However, you should avoid bare-handed contact when handling any dead animal. If you must pick up a dead bird, use gloves or an inverted plastic bag to place the bird’s carcass (body) in a garbage bag." REF: https://www.cdc.gov/westnile/dead-birds/index.htm