Nests of Birds
Nests of the Chestnut-collared Swallow (Petrochelidon rufocollaris) made of mud mixed with vegetal matter.
Nest of Birds
Definition: The nest of birds is the place and structure chosen and built by a single, a pair, or multiple birds with the purpose of laying and incubating the eggs, as well as, sheltering and rearing the young.
The nests of birds vary according to the taxonomy and natural history of the species. Orders, families, and species generally have similar nests.
Because birds are descended from a group of dinosaurs called theropods, birds and reptiles show certain similarities in some aspects of their reproduction. However, birds are much more advanced in terms of the courtship to find a mate, the construction and positioning of their nests, and the care of their progeny. In this article, we talk about the characteristics of the most common types of bird nests.
General Aspects of the Nests of Birds
The most common type of nest built by birds is the cup-shaped nest. But there is a great variety of shapes, sizes, substrates, and materials that birds use to make their nests. The shape, material used, and positioning of the nest respond to basic needs of the birds, which are to protect the eggs and chicks from inclement weather and perhaps more important the protection from predators.
Types of Nests
The choice of the place where the nest is located and its construction are extremely important events because this will be the place where the egg-laying, incubation, and caring for the young activities take place. The nest is a structure built or conditioned by the parents, although sometimes they can use a natural depression of the land or existing nest. Depending on the location of the nest, parents may camouflage the nest or cover the eggs with twigs and dead leaves to conceal them from possible predators.
Nest in a depression in the ground. See the nest with two eggs in the lower center part of the photo.
Common Types of Bird Nests
Nest in a Depression on the Ground
This is one of the simplest constructions of nests and consists of a small depression in the ground or vegetation. This depression has to be deep enough to prevent the eggs from rolling out of the nest. The depression on the ground is sometimes reinforced or lined with pieces of vegetables, branches or even small rocks. Depression in the ground as nests are used by quails, most shorebirds and seabirds, rails, and nightjar.
A mound nest consists of a pile of plant material and dirt with buried eggs. The decomposition of the material generates heat, which imitates the incubation process. Nest of a Megapode (Leipoa ocellata). Photo: Glen Fergus/Wikipedia.
Nest in a Mound
This particular form of nesting includes the construction of a pile of plant material and dirt. The eggs are placed in the middle of this pile and buried with more branches, dirt, and leaves. The mounds and eggs are abandoned by the parents. The decomposition process of organic matter radiates heat, which incubates the eggs until they hatch. The chicks never know their parents and they find food and take care of themselves from the moment they hatch. The size of these nests can reach sizes of more than 100 m2 of material. Mound nests are exclusive to the Megapods of Australasia.
Burrow in a vertical dirt bank inside the forest. Nest of Momotus sp.
Nest in a Burrow
Most birds that construct this type of nest dig their own burrow but others use abandoned or already existing burrows dug by other animals. The purpose of this type of nest is to lay and incubate the eggs and protect the chicks from the elements and predators by positioning and taking care of them underground or out of sight of possible predators.
Female of a Versicolored Barbet in a cavity in a dead and rotten trunk. Barbets can dig their own cavities as well as use already-made cavities.
Nest in a Cavity
This type of nest consists of a chamber located in the wood of living or dead trees or trunks of arborescent ferns or cactus. Nests in cavities also include chambers dug in termite nests. The nests in cavities in wood are found in any region where there is wood as a substrate. The nests in termite nests are mostly restricted to tropical regions where termite nests are prevalent. The birds using cavity nests include woodpeckers, toucans, trogons, barbets, as well as a few members of the family Tyrannidae (flycatcher), which use existing cavities.
The nest in the form of a cup or bowl, with some variations, is the most common bird nest type.
Nest in Cup or Bowl
The nests in the shape of a bowl or cup are mostly circular or semi-circular in shape. It can also be said that this type of nests has the shape of a cup or half a cup. The materials used for the construction of this type of nests vary between purely plant material and threads of spider webs or caterpillars, mud, lichens, saliva that the bird produces or a mixture of mud or saliva with plant materials.
Depending on the materials used, these nests can be flexible or rigid. They can be placed on a simple branch, in crossings of branches or pitchforks, as well as, in the case of nests made with saliva, be glued to vertical rock or similar substrates. Cup-shaped nests are the most common and are made by most birds. Birds that use this type of nest include sparrows, thrushes, warblers, and swifts.
A platform nest is generally re-used for many years. The pair using the nest adds a layer of material each season making the nest grow in size each year. Photo: Neil Demaster/Flickr.
Nest on a Platform
As its name says, platform-type nests are in themselves an accumulation of plant material with a flat surface with a depression in the center to house the eggs and prevent them from rolling out of the nest. The platform nests are generally placed on bifurcations of large branches between which the material is first placed as a base. Then, additional material is added.
In general, platform-type nests are used by the same or different pair for many breeding stations. The users add a new layer of nest material and this is how the nest grows in size every year. The nest can grow in size and add weight to the point that it causes structural damage to the substrate that supports them. If the nest falls by the size and volume, it is usually reconstructed in the same structure if the structure still remains. Birds that make platform nests include herons, storks, and birds of prey among.
A Russet-backed Oropendola (Psaracolius angustifron) arriving at its hanging nest. Hanging nests are prevalent in the Icteridae family.
The hanging nests are the most sophisticated among the nests of birds. There are many types of hanging nests and they usually have in common an upper part of varying length woven to the support branch, a chamber, and an entry at variable locations on the nest. The entrance can be close to the part where the nest is woven to the branch, to one side of the chamber, as well as, at the bottom of the nest. In some hanging nests, the entrance is covered with nest material and it is difficult to see where it is.
The shape, size, and placement of hanging nests are very variable and specific to certain families and birds. Most species within the family of Icterids (Orioles and caciques), as well as several species of Flycatchers of the Tyrannidae family, build hanging nests.
The spherical nests have a roof with a lateral entrance that is usually camouflaged.
Spherical nests generally have a spherical shape or a shape that conforms to the structure in which they are built. The spherical nests have the appearance of being an accumulation of twigs and leaves with an entrance also concealed and difficult to detect. Inside there is a very well woven cup where the eggs are placed and the chicks grow. The spherical nests are usually placed in hidden places and the non-striking appearance responds to the intention of going unnoticed by predators.
Gannet Piqueros nesting colony. Photo: Shellie / Flickr.
Individual Versus Colony Nesting
Most small birds that nest individually must deal with the risk of predation of their clutch and chicks by placing and building a concealed nest. Large birds have exposed large nests because they can defend their eggs and chicks against most predators.
Small birds also build an exposed nest in colonies. Birds nesting in colonies can detect and defend their nest more easily by having many more eyes watching and many individuals attack and repelling predators from their nests.
Another advantage of nesting in colonies is that synchronized breeding produces many eggs and offspring at the same time. Predators can only take so many eggs and chicks at one time before they are satiated. Predation in colonies results in a proportionally smaller loss at the population level than if the same birds would nest individually over a longer period of time.
Colonies can also serve as an information center. Birds that were not successful at finding food can follow those birds that are better able to find food.
- Gill, F. (1995). Ornithology. W.H Freeman and Company, New York.
- Wimberger, P. H. (1984), The use of green plant material in bird nests to avoid ectoparasite», Auk 101: 615-616