I've noticed my mare is a little sensitive lately. Usually she is a very calm horse with a good head on her shoulders, but lately she's been a bit jittery and very alert with everything around her. She's got a lot of pent-up energy in her as well and gets a little impatient being in the barn. She's not badly behaved mind you, just a little more "alert."
Today I was hand-walking and hand-trotting her up the road and she spooked at something, I have no idea what. She rarely spooks, but today she actually seemed AFRAID. I could really sense it in her. I think one defense mechanism for her is putting up her dominant front -- meaning, she tucks in her chin and does a head frame, and kind of prances. She was getting a head of me a little when I was leading her.
I calmed her down as best I could by talking to her and petting her, but I decided to bring her back to the barn because she really did seem scared of something. It could have been a coyote or a bear she smelled in the air, because we have both around the barn. Or, she could just have been a little hyper-sensitive and hearing all the "weird" sounds of Spring. With the snow melting, water is rushing everywhere, etc.
I find the more time I spend with her, lunging or walking or riding or whatever, she seems to calm down. I think its mainly her having a lot of energy from standing around in the snow all winter. She is by no means a spooky horse. She just seems a bit more sensitive to things these days...