All birds lay eggs, but where they care for them and how their young develop can be remarkably different from species to species. This spring, I've been watching several families of birds.
Barred owls don't do any home building. They search forests for old, decaying trees with readymade cavities. They don't do anything to the space. It must be in move-in condition or they will move on. Once their young can regulate their own body temperatures, they spend several weeks sitting on branches near the nest before they attempt to fly.
Flickers, a medium-size woodpecker, also look for decaying trees, but they spend a significant amount of time building their homes. Both the male and female drill an opening that's barely wider than they are. Once inside, they peck to enlarge the cavity. During the construction season, you'll see a flicker fly into the tiny hole and minutes later stick its head back out with its beak full of wood chips, which it spits out onto the ground below. When the cavity is large enough for an entire flicker family, it continues to peck to generate more wood chips, which it leaves in the nest for softness and insulation.
Bald eagles mate for life and use the same nest year after year. Like many humans, though, bald eagles seem to want larger and larger dwellings. Each year, they add onto their nests. As a result, bald eagles have the largest nests of any North American bird. Their nests can be more than 8 feet wide and weigh more than a ton.
Ducks and geese typically nest on the ground in somewhat hidden areas along a pond or body of water that's relatively still. The wood duck, however, nests in tree cavities. As soon as they're able, their young ducklings jump from the nest into the water below. With ducks and geese, the young can be swimming less than a week after they hatch.
When photographing nesting birds, it's critically important not to disturb them. Nesting season is the most sensitive time of year for any bird. Even a minor disturbance can cause them to abandon their nest.
My nesting photos are typically captured with a 600mm lens with a "doubler" attached. This combination gives me the equivalent of a 1200mm lens. This combination allows me to fill the viewfinder with a bald eagle's nest, for example, even though I'm nearly 200 feet back from it.
Powerful lenses are a serious investment, but not having one is no license to jeopardize wildlife. For that matter, having such a lens doesn't give you that right either.
Frequently, even I wish I had a more powerful lens. For smaller nests, like the flicker, I still keep my distance. I just crop the image later in Photoshop. Technically, the pixels in the image would be of higher quality if I got closer, but no image is worth risking the lives of animals. Besides, it's better for the birds, and the artistic quality of my images, if they aren't the least bit interested in me.
If you're aware of a nest near you, feel free to photograph it, even if you don't have a huge telephoto lens. Just keep your distance and crop the image later. Or just observe the birds through binoculars. I enjoy watching wildlife even when I can't get "the shot."