The bird and its nest, where everything starts…
Conclusion of the study of non-passerine’s nests
Throughout these pages, we were able to admire the ingenuity of the birds at the breeding time. From the selection of a nest-site and the nest-building to the first flight of the young, many obstacles have been overcome.
If some vulnerability is clearly apparent, especially for nests placed on the ground, this problem is generally compensated by a carefully chosen location. The birds that lay their eggs on rocky ledges in cliffs are in an environment only accessible to birds. Eggs laid directly on the ground, in sand, gravel, pebbles, or earth, usually have a cryptic colour similar to that of the soil. In the case of vegetated areas and grassy field, grasses or leaves are used to camouflage the eggs when the adults leave the nest for foraging and feeding.
The nests of numerous waders are a simple scrape almost invisible, and the eggs merge with the ground.
Several birds nesting on the ground have a cryptic plumage and are almost invisible when they sit motionless on the nest, among the leaf litter. Have you ever tried to find a nightjar on its nest? You will need good eyes!
The floating nests are threatened by variations in water levels but they are usually anchored to aquatic plants. However, every year, numerous nests are flooded during heavy rains, and the nesting burrows suffer the same threats or the birds are killed by predators.
The nests built in trees offer more protection, but they also have some predators such as snakes, larger bird species and arboreal mammals, and in addition, the bad weather. However, the big nests of raptors, herons, storks and other large birds are placed high in trees, or on old buildings, poles or cliffs, in order to provide good access to these imposing birds.
But the most protected eggs are probably those of the cavity-nesters. The brood is well-protected and invisible from the outside. Unlike the eggs of birds nesting on the ground, the eggs of these species are often white, because they don’t need to be camouflaged.
The colonial-nesters are protected by the high density of breeding pairs, but sometimes, disputes break out due to the close proximity of the nests. And they are vulnerable to disturbances when the colonies are established on beaches.
Examples are numerous. The birds put special care in nest-building. This structure must provide protection, shelter and safety to the chicks, in order to help them to grow and fledge and fly away from their parents to become independent.
The nest is their home. Numerous species reuse the same nest in several following years, whereas other birds build a new nest each year, sometimes in the same site or close to. The nest-site is usually close to the foraging areas, and the chicks can be fed regularly.
This is not the case of penguins, albatrosses and other seabirds that have to travel long distances to find food. But parents take turns and the chick is always under the protection of an adult.
We have learnt a lot about the nests of non-passerine bird species. The next study will be about the nests of Passeriformes, a very long work indeed, but these small birds are able to build wonderful, ingenious, elaborate and sometimes surprising nests. They deserve our full attention !
Many thanks to the photographers! The high quality of their images and the diversity of the photographed species allowed me to make this study and to display numerous photographs in order to explain, better than words, how the birds are nesting.
You can find their galleries here:
The Photographers
Text by Nicole Bouglouan