I find that being overly in tune with nature you tend to pay attention to the little things. The way the leaves move, how a passing animal looks at you, weather patterns, planting, blooming, fruiting, harvesting, seeding. Without this consciousness we cannot call ourselves witches.
Many animals live around us in the Thicket. I've gained their favor by holding funerals for their fallen, but more importantly I feed them. I grow flowers for the insects, leave seeds for the birds, and offer fruits and veggies. And sometimes a little bit of our dinner for the bigger critters.
I nearly missed this bumblebee as I went out onto the balcony to replant the strawberries (I've been meaning to for weeks, just haven't gotten around to it) plus clean up and sweep the outside altar. He was sleepy so I moved him from the floor to the iron table outside where he sat, little purple wings glistening in the sun. We have a nest of bumblebees outside my altar room window and they see and hear many of my spells and rituals. I find them rooting around my plants and outside altar. They slam into the windows like little drunkards. And they come to me often. Sometimes as an omen, sometimes to say hello.
Most witches will say that animals come to them to die. For some this is true, even the smallest beast has put themselves in my path to ease them into the Otherworld. Remember the Mockingbird and Squirrel? Also, plenty of insects find their way into my little home. It's our reverence that draws us to them and them to us.
All this being said, do I consider all animals messengers? Yes and no. All animals have connections to the divine. Some do a better job of getting those messages through; birds, insects, rabbits, you know the types. Sometimes I find it easier to work with tactile animal spirit messengers. When I call upon spirits, I'm also calling on animals I've worked with or helped. Who are yours?