Peter Goodfellow 2011. Avian Architecture: How Birds Design, Engineer & Build. Princeton University Press, Princeton and Oxford. 160 pp. ISBN 978-0-691-14849-6.
Birds build nests when they are in the breeding mode. These nests serve as secure containers for their eggs. Here, the chicks are raised until they fledge, after which the nests are mostly abandoned. These nests come in a variety of shapes and sizes, each with its advantages and disadvantages in terms of exposure to predators, ability to avoid detection and how the chicks adapt under these circumstances.
In the book, the author has grouped nests into 12 categories. The cup-shaped is the classic model and the commonest of all nests. Found firmly lodged between the forks of branches, those of the Yellow-vented Bulbul (Pycnonotus goiavier) can be commonly encountered in any urban areas in this part of the world LINK (below left). Spider silk is sometimes used to secure the nest, especially when it is attached to horizontal branches, as seen in that of the Common Iora (Aegithina tiphia) LINK.
Cup-shaped nests can be modified to give protection against sun and rain by providing a dome above, as seen in the nest of the Mangrove Pitta (Pitta megarhyncha) LINK.
The simplest nest is a mere scrape on the ground as made by most terns LINK and nightjars LINK. Flamingoes similarly construct a simple nest, except that is makes a slight mound with a depression at the top to hold the eggs. This is categorised under mound nests.
Platform nests are also simple to construct. Built with twigs or branches lodged in trees and shrubs, the simplest seen are those of doves and pigeons LINK and the more complicated ones are built by many raptors LINK. Aquatic birds like grebes LINK make a floating structure anchored between plants growing in the water, the so-called aquatic nest.
Then there are the hanging nests, usually woven and stitched as in those of weaver birds LINK and sunbirds LINK. With tailorbirds LINK, the nest is built between the sides of a curled leaf.
There are some birds that nest in cavities. The primary hole nesters chisel a cavity from an old rotting tree trunk like barbets LINK or excavate a tunnel from a mud bank as in bee-eaters LINK. Secondary hole nesters make use of cavities abandoned by other animals, as seen in hornbills LINK and parakeets LINK.
Mud nests may be open cups made by Pacific Swallow (Hirundo tahitica) LINK or an enclosed structure with an entrance as in Cliff Swallow (Petrochelidon pyrrhonota).
An interesting category is the “edible nest and food store.” The former is seen in the nest of the Edible-nest Swiftlet (Aerodramus fuciphagus) that uses its saliva as nesting material. The latter is encountered in shrikes LINK that impale prey on sharp spines to serve as “pantries.”
The court and bower nesters are a unique group where the male build the decorative bower LINK to entice females (above right) while the female leaves after mating to build a normal nest to raise the young.
A major group is categorised under “colony and group nests,” where the nests include the various architectural types featured above. The former is where numerous pairs nest in close proximity to their neighbours. This is seen in many species of penguins, terns, swifts and martins. The latter is seen in the Social Weaver (Philetairus socius) where many individuals cooperate to build a huge structure but each pair has a separate compartment.
Each chapter of the book covers a specific category of nest, followed by blueprints, materials and features, and case studies. The book is lavishly illustrated, covering more than 100 species of birds from all over the world. I find the book an easy read, full of useful information on how and why birds build the various nests that birdwatchers study and photographers document.
The author is a retired English teacher and lifelong birdwatcher. Besides Avian Architecture, he has published Birds as Builders and A Naturalist’s Guide to the Birds of Britain & Northern Europe. A serious birder, Peter Goodfellow can serve as an inspiration to our newer birdwatchers – to enthuse them to become citizen scientists rather than mere tickers and listers.
(Image of Yellow-vented Bulbul’s nest by YC Wee and that of Satin Bowerbird (Ptilonorhynchus violaceus) by Dr CH Lee)
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