The moment you get your binoculars on a bird it flies away.
You birdwatch with a group. A good bird is spotted. When you get on the bird, someone moves to stand in front of you, blocking your view. Or, an overenthusiastic someone comes to stand beside you, jolting your arms away. The someone doesn’t realize what they did.
A warbler plays hide-and-seek behind thick foliage.
You are observing a raft of ducks and find a mystery duck. Just as you begin to study it for diagnostic markings, the duck takes off.
The accipiter sp. is silent.
The bird is between you and the sun. Back-lighting ruins your enjoyment of looking at the bird. You have no way of circumventing so that the sun is behind you. The dark splotch doesn’t care.
Your binoculars won’t stop fogging up.
You are observing a special bird. A raptor appears out of nowhere and catches the bird for a meal.
Someone in your group spots a bird. Initially, others struggle but eventually get on it. Everyone but you sees it.
You are on a bird. While trying to move to view it from a different angle, you trip.
You deceive yourself into thinking that any moving inanimate natural object is a bird. Falling leaves are especially irksome. Or, you spend minutes trying to identify a bird, and you finally discern it is actually a stump. Or, you are birdwatching by car, catch a glimpse of a large bird among a clump of trees, and turn around to get a better look – only to learn to that what you saw is a tattered paper sign billowing in the wind.
There are no birds.
You leisurely spend time observing a bird. Suddenly, a loose dog runs close by and the bird takes off. The dog’s owner is nowhere to be seen.
It is raining.
It is very windy. The birds have taken cover and refuse to come out. This is especially loathsome during a Christmas Bird Count.
A perched passerine faces away from you. You can only see its back. It won’t ever turn around, or budge. The bird is all back.
You chase a bird. You arrive, but you just missed it.
You chase a bird. The location is far from where you live. You spend hours trying to find it with no success. You leave. Sometime after, the bird is spotted again.