In situations when there are physical limitations to approach birds, such as those on the water, high magnification binoculars are the best solution. On the other hand, to observe birds from a relatively close distance when they more relatively quickly, a wide field of view binoculars at around 10x magnification might be your better option.
IS modes can be selected depending on the usage: Normal IS is good for viewing birds flitting around while POWERED IS is good for viewing birds perching on trees.
If you are viewing from a distance, binoculars with a higher magnification of 10x or more is recommended. As image shaking is more obvious on binoculars with 8x magnifications or higher, make sure to choose a pair with an IS function.