Two Short Stories: Cat and Geneticist

[Ruthless Editor]

I'm trying to find the author/name of story/any further information about the following short sci-fi/fantasy stories:

1) I probably read this story in a collection of short stories that I checked out from our public library about 12 years ago. I read it to my daughter and she wants the story to read to her school kids.

A story about a cat who persistently drags home her 'catch of the night' -- on one occasion, she drags home a leprechaun (I think it was a leprechaun -- or some other mythical creature of like nature.)

2) I'm fairly certain these "genetics" stories were in Isaac Asimov collections, either the magazine or an anthology of short stories from the magazine. I'm hoping the author has an anthology of all the stories at this point.

A story about geneticist who designs brightly colored bats to control an enviromental problem her group of settlers are having on the planet they settled. Also, either from the same story, or a story by the same author set in the same world -- in the eradication of some noxious weeds, they find they are endangering a species of bird who lays it's eggs among the weeds.