birch.prod.bigleaf.net has no CNAME records.
Question and response
Question
dig birch.prod.bigleaf.net. NS
Answer
The response has no answer records.
Authority
bigleaf.net. 600 SOA bigleaf.net. admin.bigleaf.net. 1772064000 3600 120 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0