For the prefix, use the day you were born on. For the suffix, use the month. If you're not comfortable sharing your birthday, use a random date— today's date, holiday, etc.

Prefix:
1. Black
2. Crow
3. Raven
4. Coal
5. Dark
6. Shade
7. Pitch
8. Dim
9. Dusk
10. Night
11. Gloom
12. Jet
13. Grackle
14. Starling
15. Misty
16. Dull
17. Clouded
18. Soot
19. Sable
20. Murky
21. Panther
22. Storm
23. Eve
24. Twilight
25. Cold
26. Mist(y)
27. Fog(gy)
28. Ink(y)
29. Slate
30. Sloe
31. Faded

Suffix:
January: claw
February: face
March: foot
April: pelt
May: whisker
June: feather
July: tail
August: heart
September: fur
October: shade
November: cloud
December: step

I'm Shadetail.

Sources
• http://www.surfbirds.com/namericanbirds/blackbird-cardinal.html
• https://www.thesaurus.com