Sunday, July 31, 2011

Review: The Nesting Season

In North America, most birds are wrapping up another breeding season. Some, like Arctic shorebirds, are already leaving their breeding grounds and heading south for the winter. Other birds may be feeding fledglings. Still others may be working on their second or even third broods. Some, like American Goldfinches, are just getting started since they wait for the late summer crops of thistle seeds to become available. Bernd Heinrich discusses all of the activities that go into a bird's reproductive cycle in his new book, The Nesting Season: Cuckoos, Cuckolds, and the Invention of Monogamy.

Reproduction is a core instinct for birds, along with escaping predation and finding enough food to survive.  Reproduction means more than the brief cloacal kiss that most birds use to copulate. Birds have particularly complex reproductive lives. There are a variety of preparatory activities for mating and nesting, and after copulation, the parents need to incubate and care for their offspring. Many of them migrate, which affects when they can start and end their breeding seasons and how their young develop must take account of that.  Most birds also bear young that require substantial care in their early stages so that adults cannot just lay the eggs and leave like reptiles do. Even precocial chicks need some feeding from adults and careful shepherding to keep them from harm. Nest parasites like cowbirds and cuckoos come the closest to abandoning their eggs, but even those birds need to watch their hosts carefully prior to leaving an egg to make sure that the nest is in use and that the timing is right.

Each chapter discusses a different aspect of nesting: establishing a territory, finding a mate, avoiding predation and parasites, selecting a nest site, building a nest, laying eggs, and care for the young after they hatch. Heinrich chose to focus on common problems in reproduction and then discuss how different species approached and solved them. Since Heinrich spent his early years in Germany and traveled in Africa, he is able to incorporate European and African species into his discussion of nesting behaviors, in addition to the birds that will be more familiar to North American readers.

This may sound somewhat dry, but Heinrich's writing keeps the text lively, even over the nearly 300 pages of text. Heinrich builds each chapter around his own observations, which seem to be drawn from his notebooks. To introduce a new topic, he first presents a series of dated observations. These may be the dates bird species arrive in the woods around his home or records from when he checked birds' nests for their contents or materials. Any such observations are related in first person so that the text feels like storytelling even after Heinrich shifts from his own observations to the theoretical explanations for birds' reproductive behavior. This structure suggests not just a writing style but a method. Observation sparks curiosity and investigation, which in turn leads to a better understanding of birds' behavior. This suggests a model that birders could emulate, though some of Heinrich's experiments (especially ones that involve climbing trees or dissecting dead birds) will probably not appeal to many birders to carry out themselves.

I have not read many of Heinrich's other books (a situation I am trying to remedy) so I cannot compare this book to them. However, I can say that The Nesting Season: Cuckoos, Cuckolds, and the Invention of Monogamy is a highly readable and informative discussion of birds' nesting activities. I would recommend it to anyone who wants to learn more about how birds manage their breeding responsibilities or for general nature reading.

This review is based on a copy provided by the publisher.