how do birds find their nests

Birds nests are familiar structures, yet we know surprisingly little about them. Research is starting to reveal how these homes function

Given that a birds nest is something so commonplace, it is strange that we dont really understand how or why they are constructed. With recent research, however, we are beginning to understand what causes such variation, and how nests function.

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How the song thrush builds its nest

how do birds find their nests

A female song thrush chooses a location, usually a triple branch fork, and builds a twig base platform there. This is then filled with moss.
She weaves grass stems into a cup by tucking and twisting them into one another. Finer grasses are woven into the rim for strength.
She covers the outside cup with moss and a few leaves to make it look more natural. She then lines the nest with wood pulp and mud, smoothing it down with her body.

How do birds build nests?

How these materials are used also varies. The bullfinch constructs its stick nest near the tips of its branches, using the strongest twigs at the base. In contrast, the larger hawfinch builds its nest in the bend of a branch close to a tree trunk, where it can receive the most support from below. The strongest twigs are then positioned around the sides of the nest, where the most support is required. Both species’ “twiggy” nests may seem fragile, but it is surprisingly difficult to disassemble them.

What are nests made of?

Hence, why do birds build their nests in such a diverse manner and with such a wide range of materials? Does all of this work actually succeed in keeping the eggs and chicks warm, safe, and secure, and if so, how?

Both the blackbird and the bluetit need to expend more energy than twice their bodyweight in order to build their nests, which in turn forms their eggs. The blue tit’s clutch of ten eggs is the same weight as she is. Therefore, anything that reduces the amount of heat lost from the nest will assist the adult in preserving its energy reserves. The adults who are incubating will stay healthy and be able to successfully hunt food for their soon-to-be hatchlings.

Nonetheless, a nest is not a simple egg-container. The structure of the walls can be intricate, and they are made of an astonishing variety of materials derived from plants and animals that change depending on the climate. Blackbird and tit nests are better insulated in the north during the colder springs than they are in the warmer south. However, studies have revealed that a variety of small garden bird species construct nests that offer, generally speaking, comparable levels of insulation despite this variance.

The amount of moss and hair in the nest walls appears to have an impact on insulation. With differing degrees of success, birds seem to have discovered a variety of solutions to the heat-retention dilemma. For example, chaffinches line their nest cups with an abundance of feathers and hair, according to research done in my lab. Even though this layer is only 610 cm thick, or roughly one-third the thickness of the wall, it accounts for 90% of the total insulation for the entire nest wall. In comparison, the grassy blanket lining a blackbird’s nest, while the same thickness, only provides 40%

The poor old blackbird is suffering from the current weather while the blue tit is snugly in her little nestbox, preparing her eggs. She keeps the eggs from getting wet and cold by tightly covering her clutch when it rains, allowing the water to run off her back and into the nest walls.

When it rains, a nest’s constituent materials are very important. Even though the nest wall allows water to drain freely, some of it will be absorbed. Particularly moss absorbs moisture like a sponge, so it will take a long time for a nest covered in moss to dry out. On the other hand, moss-free nests quickly dry out. For example, the “classic” stick nest of a hawfinch drains very freely and dries out quickly. Blackcaps appear to achieve the same result by merely constructing their nests out of grass.

A degree of moisture is important, though. During incubation, eggs must be maintained at an appropriate humidity level to prevent excessive water loss through their pores. Because the walls of the nest are rather leaking, vital oxygen can enter and carbon dioxide can exit. It appears that they can also hold onto just the right amount of water vapor to bring the nest’s humidity up to the required levels, kind of like a fluffy duvet.

Because a nest must be able to support the weight of both the incubating bird and its whole brood of nestlings, it must also be structurally sound. A bird species’ dependence on woody materials for structural integrity increases with size.

FAQ

How do birds know where nest is?

There are magnetic anomalies birds may recognize as intrinsic earth features. For instance, homing pigeons use landmarks like buildings to help find the way back to their domicile. A few species, like storm petrels, may even use smell to find their home burrows.

How do birds choose where to nest?

To deal with flying predators, birds look for places where they can hide or at least partially cover their nests. There’s a reason the cliche of the nest in the nook is ubiquitous; a nook provides great cover in every direction but one. Birds look for high places in homes where they can nest.

What do birds do when they lose their nest?

If an active nest is destroyed late in the breeding season, or if the birds belong to a species that doesn’t re-nest, the birds will simply move into the non-breeding part of the year. Some species will build a new nest and try again, if the loss is early enough in the year.

How far away do birds fly from their nest?

These range from 15 to 55 miles per hour, depending on the species, prevailing winds, and air temperature. At these rates, migratory birds typically fly from 15 to 600 miles or more each day.