Birds build nests in a variety of shapes and sizes to meet their needs for breeding and raising young. The type of nest built depends on the species of bird, the location of the nest, and the materials available. One distinctive nest type is the domed nest. Domed nests are closed nests with a small entrance hole on the side or bottom. The dome shape provides shelter, regulates temperature, and protects eggs and chicks from predators and weather. Several types of birds around the world build domed nest structures.
Birds that Build Domed Nests
Here are some of the most well-known birds that build dome-shaped nests:
Weaver Birds
Weaver birds are small passerines found throughout Africa, Asia, and Australia. There are over 100 species of weaver birds, and many are known for their elaborately woven nests. The nests are often retort-shaped with a domed top and a long entrance tube on the bottom or side. The nest entrance is just big enough for a bird to pass through. Weaver birds build nests by weaving together grasses, twigs, and fibers. The nest materials are woven and knotted to form a sturdy structure. Different weaver bird species build nests of varying shapes, sizes, and materials. Sociable weavers build large community nests housing over 100 pairs, while other species have smaller nests for individual pairs.
Ovenbirds
Ovenbirds are small insect-eating songbirds found throughout North and South America. They get their name from their unique domed nest shaped like an old-fashioned oven or Dutch oven. Ovenbird nests have a round central chamber built on the ground or low in a tree or shrub. The nest roof has a side entrance and is made of interwoven grasses, leaves, rootlets, and bark strips. Inside, the nest chamber is lined with softer materials like hair and feathers. Ovenbirds carefully cover their nests with leaves or other camouflaging materials to hide them from predators.
Penduline Tits
Penduline tits are tiny songbirds found across Europe, Asia, and North Africa. They build elaborate domed nests with a side entrance hole. Their nests hang from branches of trees and are constructed from plant materials like seed fluff, grasses, and lichens. The nest materials are bound together with spider silk and cocoons to make a strong, weatherproof structure. The inside of the nest is lined with soft feathers and fur. After the eggs hatch, the weight of the growing chicks causes the bottom of the pendulum nest to swing downward.
Buff-Necked Ibis
The buff-necked ibis is a wading bird found in marshy wetlands of Africa. Using reeds and sticks, buff-necked ibises build large domed nests high in trees near water. Their massive nests are up to 6 feet wide and can be reused year after year. Several pairs may nest together in a single tree colony. The dome shape helps protect the eggs and chicks from predators and shields them from sun and rain.
Bush Thick-Knees
Bush thick-knees are shorebirds found in Australia and Southeast Asia. They build simple ground nests called “scrapes” that are sometimes domed over. Using bark, grasses, and sticks, they construct a partial roof over their nest scrapes. The small entrance is on the side. Bush thick-knee nests blend in with their surroundings in open woodlands and savannas.
Advantages of a Domed Nest
The dome is an efficient and protective structure for nest building. Here are some key advantages of the dome shape:
Shelter from Weather
A domed roof shades the nest from direct sun and insulates from extreme temperatures. It sheds rain and protects from wind. The rounded shape is aerodynamic and resists damage in storms.
Predator Protection
The closed dome with just a small entrance hole makes it difficult for predators to enter the nest. Birds building domed nests high up in trees gain further protection. Camouflaging the nest also helps conceal it from predators.
Strength and Stability
A dome structure is inherently strong and stable, as forces are distributed evenly across the curved surface. Domed nests hold their shape and remain securely attached even in bad weather.
Efficient Use of Materials
The dome shape maximizes interior space while minimizing the amount of material needed for construction. It also allows materials like grasses and twigs to be tightly woven together for structural integrity.
Microclimate Control
The enclosed dome retains heat and allows birds to control humidity and gas exchange. This creates ideal incubation conditions for eggs and habitat for chicks.
Unique Nest Shapes and Sizes
While many birds build domed nests, the size and shape can vary greatly depending on the species:
Giant Domed Nests
Some bird nests are enormous dome structures. The sociable weaver builds massive apartment-style complexes up to 6 feet wide housing over 100 pairs. Buff-necked ibises construct giant platform nests up to 6 feet across.
Tiny Domed Nests
Tiny birds like hummingbirds and penduline tits build diminutive dome nests only a few inches across. These compact nests are works of art perfectly sized for the tiny birds.
Long Entrance Tubes
Weaver birds weave nests with long downward facing entrance tubes up to 2 feet long. This makes it even harder for snakes and other predators to enter the nest.
Pendulum Nests
The amazing penduline tit nest is mounted on a flexible branch so it can swing and rock like a pendulum. This may help deter predators and regulate temperature.
Communal Nests
Some dome nests house multiple pairs of birds. Sociable weaver colonies have separate nesting chambers off a large central dome. Buff-necked ibises build single giant platforms for the whole colony.
Unusual Materials for Domed Nests
Birds construct domed nests from diverse organic and man-made materials they can weave and interlock including:
Plant Fibers
Grasses, leaves, vines, roots, bark strips, and twigs are commonly used as building materials. Different lengths and flexibility allow weaving structures.
Spider Silk
Some birds like the penduline tit weave together materials using sticky spider silk. The silk acts as a natural glue and seals the dome.
Feathers and Fur
Birds line their nests with soft feathers and animal fur for insulation. The Wind River canopy dome nest even incorporated bones among the materials.
Discarded Plastic
Unfortunately, weaver birds in urban areas may incorporate plastic thread, string, and trash into nests where natural fibers are scarce.
Mud Adobe
The Village weaver bird uses mud to construct retort-shaped nests in eaves or embankments. The mud hardens into natural adobe bricks.
Notable Domed Stick Nests
Here are a few remarkable examples of large stick dome nests constructed by innovative birds:
Wind River Canopy Nest
In 2016, a female common raven built a 6-foot wide domed nest atop a Douglas fir in Washington’s Wind River valley. Dubbed the “Wind River Eagle’s Nest”, it incorporated an astounding variety of materials woven together, including twigs, wires, deer antlers, feathers, bones, and plastic.
Long-billed Corella Nest
In 2009, a colony of long-billed corellas in Australia constructed massive domed nests up to 6 feet tall weighing over 600 pounds. The branches supporting one nest snapped under the weight. Their huge communal nests contained multiple chambers.
Altamira Oriole Basketball Nest
In 2006, Altamira orioles built a classic hanging pouch nest that ballooned in size to an over 4-foot diameter sphere. Dubbed the “basketball nest”, it was composed of vines and green leaves skillfully interwoven.
Construction Techniques for Domed Nests
Building a domed nest is an impressive architectural feat requiring engineering expertise. Here are some construction techniques used:
Weaving and Knotting
Most domed nest builders like weaver birds tightly weave flexible materials and use specialized knots. This forms a strong framework shaped into a dome with a secure floor.
Mud Layering
The village weaver bird molds mud pellets around a central ring of grasses. More layers are added and smoothed to construct the hard shell-like dome.
Spiral Branch Layering
Some large stick nests are built by laying branches in an upward spiral pattern. More cross branches fill in the sides and woody vines tighten the dome walls.
Tree Attachment
Tree nests are carefully engineered to attach securely to branches in the high canopy. Some hang pendulum style while others integrate into multiple forks.
Camouflaging
Many dome builders conceal their nests by covering them with materials matching the surroundings. Ovenbird nests look just like part of the forest floor.
Threats to Domed Nests
Despite their secure construction, domed nests face threats from both nature and manmade factors:
Severe Weather
High winds and intense storms can damage dome nests or blow them out of trees entirely. Extended heavy rainfall can also soak and deteriorate nest materials.
Predators
Snakes, raccoons, monkeys, large birds, and arboreal mammals will raid dome nests for eggs and chicks despite defensive designs.
Parasites
Bird mites, lice, fleas and other parasites can infest the interior of domed nests, harming developing chicks.
Habitat Loss
Deforestation, urbanization, and wetland drainage destroys essential nesting habitat for sensitive bird species that build domed nests.
Invasive Species
Introduced predators like rats, cats, and snakes decimate ground and tree nesting birds and take over tree cavities needed for nest sites.
Climate Change
Changing weather patterns and reduced availability of native nest materials may make traditional dome nests less viable for some species.
Conservation of Birds that Build Domed Nests
Protecting habitat and reducing threats is critical to conserve birds that build specialized domed nest structures. Some conservation strategies include:
Habitat Preservation
Protecting wetlands, forests, and savannas from development provides essential nesting areas for sensitive birds. Trees with old cavities for nesting should also be preserved.
Nest Site Management
Providing artificial nest platforms and boxes helps supplement declining natural nest sites. Predator-proof boxes can boost reproductive success.
Reducing Predators
Controlling populations of nest-raiding predators like rats, snakes, crows, and raccoons in habitat areas can reduce losses.
Parasite Control
Treating nests chemically or physically removing old nests helps control parasites. Hygiene of nest boxes also reduces parasite loads.
Wildlife Protection Laws
Legal protections prohibiting destruction or disturbance of active nests during breeding seasons supports threatened populations.
Community Engagement
Educating the public about unique nesting birds fosters community support for conservation. Citizens can also assist in monitoring programs.
Examples of Endangered Birds that Build Domed Nests
Habitat loss and other threats have made some dome-nesting birds endangered. Two examples are:
Philippine Eagle
The majestic Philippine eagle is the world’s largest, most powerful eagle. Using large branches, it builds a 5-foot wide stick nest high in a tree with a domed canopy and side entrance. Deforestation has decimated its rainforest habitat.
Mauritius Fody
This small weaver bird native to Mauritius island crafts finely woven domed nests with long downward tubes. Invasive plants and predators brought the fody close to extinction, but its population has recovered through intensive conservation.
Future Directions in Domed Nest Research
Further scientific research could provide new insights on domed nest construction, including:
Nest Engineering
Studying the structural engineering principles used by birds to create sturdy domed nests could have bioinspired engineering applications.
Materials Science
Analysis of unique synthetic materials like spider silk woven into domed nests could inspire new biocomposite manufacturing techniques.
Microclimate Control
Understanding how domed nests regulate incubation temperature and humidity could improve artificial incubator technology to help rare birds.
Cognitive Research
Investigating how birds gain the complex building skills to expertly construct elaborate domed nest structures provides cognitive insights into animal intelligence.
Evolution of Nest Diversity
Examining how diverse domed nest designs and materials evolved across different habitats and selective pressures provides clues into avian evolutionary ecology.
Conclusion
Birds build domed nests across habitats worldwide, incorporating a range of natural and man-made materials into their intricate structures. While the size and shape of domed nests vary by species, the fundamental dome design provides key advantages for shelter, protection, and microclimate control. Unfortunately, habitat loss and other factors threaten specialized dome-building birds. Targeted conservation efforts combined with further scientific research into their amazing domed architectural abilities can help ensure the continuation of this unique nest building tradition.