The book review journal Kirkus Reviews featured mysteries and thrillers in its February 1, 2007 issue, and listed what they referred to as “The 10 Biggest Brands.”
The “brand” that really caught my eye was “Kitty Sleuths.”
Ever since Mr. and Mrs. North's cat Pete helped solve a mystery all the way back in 1939, feline flatfoots have grown in popularity.
Shirley Rousseau Murphy has her Joe Grey, Carole Nelson Douglas has her Midnight Louie, Lilian Jackson Braun has her Koko and Yum Yum, and Rita Mae Brown (along with her feline co-author Sneaky Pie Brown) has her Mrs. Murphy. 
There are also plenty of good canine mysteries out there for dog fanciers.
Tonight after Westminster why not curl up with a barking good dog story?
Laurien Berenson’s character Melanie Travis is a Connecticut dog trainer. Carol Lea Benjamin’s P.I. Rachel Alexander and her pit bull sidekick Dash (short for Dashiell) cover ground in New York City familiar to all of us. And if it isn’t cold enough for you here, you can let Sue Henry’s Jessie Arnold and her sled dogs “mush” you out into the Alaskan wilderness.
I remember reading an old Perry Mason mystery called The Case of the Perjured Parrot, but I don’t know of any series featuring bird detectives. Now there’s a niche just waiting to be filled!