When you start to draw animals most people use photographs. When you start nature journaling you are at the mercy of the animals. Will they stay for more than a few second in the poses you started? Not likely. This is where quick gesture drawings come in handy. If you have ever been in a live model drawing class you know that the drawing will start with a few 30 second gesture drawings. There is no way to get a good drawing in 30 seconds but you can get the gesture, or the essence of that figure. This is not only warm up drawings for longer poses but getting the gesture or essence of your subject is vital. This skill becomes extremely important when drawing some animals, especially songbirds. Learn to sketch quickly and multiple poses. If the animal moves, make a new sketch. When/if the animal goes back to a pose you started, finish it! I spent the time on the ride home from the zoo to add ink and some sloppy watercolors. Make all your time count!
If you can do it the zoo is a great place to try this out. If you really want a challenge, take a toddler with you!