Hong Kong 148 Bird Flaw?

Hi all! I was sorting through a tote of stamps and found this set in an envelope. I shared this set in a group I am in and someone commented, and I quote, " it looks like you could have a error on the left hand side of the flag pole,"bird flaw".
I have done a search and have come up empty-handed. Does anyone have any information about said flaw/error? Any and all input is appreciated. I thank you in advance.

It does not look like it has the green color of the background ??.All the flaws,spots lines ect should match the background color.
http://www.silverjubileestamps.com/...lklands.html

Thank you for the link. I appreciate it.