Just like the birds that make them, bird nests come in many different forms. Depending on the size, habitat, and lifestyle of their maker, bird nests can range greatly in complexity — from simple scrapes in the sand made by many beach nesting birds, to intricately woven hanging nests crafted by birds like orioles and weavers.
Most people would probably picture the familiar grass or stick cup created by many songbirds when imagining a bird nest. Nests like this can be found nestled between tree branches and leaves or even in manmade structures or items, such as a hanging flower pot on a front porch. These cup nests may be constructed with a variety of materials, including grass and sticks, and may be lined with feathers, hair, and other fibers. Hummingbirds use materials like plants and spider webs to create small cup nests that can actually expand to accommodate chicks as they grow.
Birds such as orioles and the aptly named weaver birds make woven nests. By using their beaks to poke and pull strands of grass and other fibers together, female orioles create cozy hanging structures to hold their eggs. On a much larger scale, sociable weavers in Africa create giant woven nest complexes that hold entire communities of birds.
Some birds prefer to nest in cavities. These cavities may be premade by natural causes, other animals or humans, or they might be excavated by the birds themselves. Some examples include tree cavities, nest boxes, and a variety of other enclosed spaces. Birds that use cavities to nest include wood ducks, many species of woodpeckers, some types of owls, chickadees, bluebirds, and more. While these birds typically reside in cavities well above the ground, there are also birds such as burrowing owls that create or utilize underground cavity nests, or burrows.
Platform nests are commonly made by large raptors and wading birds, such as eagles, egrets and herons. Bald eagles create their platform nests high in the tops of trees, while wading birds will typically nest in shrubs or trees close to a body of water or wetland area. Platform nests can also be found floating on the water itself in certain areas. These nests are made by several water bird species, including grebes and gallinules.
Certain types of birds nest on cliffs and other man-made structures, such as bridges. Cliff swallows, for example, create enclosed nests out of mud that they typically attach to the side of a cliff. Some seabirds similarly use cliffs for nesting, but instead opt to lay their eggs directly on a cliff ledge with little to no nest material. While this nest placement might seem precarious, many of the birds who choose this method lay eggs that are slightly more pointed on one end, which can keep the eggs from rolling around too much.
Finally, some of the simplest nests are the scrapes created by many beach nesting birds. Using their body and feet, birds such as plovers, terns and others will create shallow depressions in the sand to hold their eggs. This nest might be located in a small territory guarded by a single pair, or some beach nesting birds choose to nest in large colonies with others of the same species or a mixed group of species. Some species that nest in colonies include black skimmers and least terns.
These examples are some of the most common types of bird nests, but there are other birds that make unique nests that might not fall in these categories. Every nest-making strategy has been tailored to each group of birds over time to best suit their needs. This process has led to the diverse array of bird nests that we can see and appreciate today.