As Pentiuum10 mentioned above, BigQuery doesn't support reading from non-Google Cloud Storage URLs. The logistics involved would be tricky ... we'd need credentials to access the data, which we don't really want to have to be responsible for. If this is a popular request, we might end up supporting external paths that are either unrestricted or support oauth2. That said, we haven't had a lot of users asking for this so far.
Feel free to file a feature request via the public issue tracker here: https://code.google.com/p/google-bigquery/issues/.