LR lets you have non-unique keywords in the hierarchy (e.g. Birds > Cardinal > Male and Birds > Goldfinch > Male), and it can work OK. But some considerations on doing this:
- It takes a little more care to search non-unique keywords with smart collections or the text-search box in the Library Filter bar. In either, you would use the criterion "Keywords Contains Words Goldfinch Male" or "Keywords Contains Words Goldfinch Female" to distinguish the two. Read carefully this section of the help to understand how LR does text matching: How to find photos in a catalog in Lightroom . It's non-intuitive and trips up many people.
- You can do exact match of hierarchical keywords by using the Library Filter bar's Metadata browser with the Keyword column. A shortcut for opening that column is by clicking to the right of a keyword in the Keyword List panel.
- When you export photos, their metadata will contain both the flattened keywords (e.g. "Birds, Cardinal, Male") as well as the hierarchical version ("Birds|CardinalMale"), but most other applications and Web services don't know how to handle the hierarchical version.
- Rather than having Male and Female as subkeywords of each species, you might make another top-level keyword Sex, with Sex > Male and Sex > Female. Then each photo would be tagged with two keywords, e.g. Birds > Cardinal and Sex > Male. This extends to other attributes of the birds you might want to record. This would reduce the need for non-unique keywords.
I would say it a little more emphatically than John did.
Sex (and similar attributes that don't depend on species) is a top level keyword, not to be placed under species. It doesn't make sense to me otherwise (although I'm sure people do this).
I thank you for taking the time to offer your advice. I appreciate!!!
Thank you John for addressing my issue. With the second response combined with your comments, will cause me to reconsider my structure and adding in this case a SEX parent keyword. Obviously this will also decrease the length of the Keyword Hierarchy in that under each bird I will not have to have Male and Female Keywords. Again thank you.