Tuesday, March 4, 2014

The Nesting Season by Bernd Heinrich

The Nesting Season: Cuckoos, Cuckholds, and the Invention of Monogamy by Bernd Heinrich Cambridge, MA, Harvard University Press. 2010 337pp. ISBN: 978-0-674-06193-4

Heinrich seems to be incapable of writing a lousy book. Once again he has taken an aspect of nature and parsed it into a highly readable book. In this case it is the nesting and rearing of chicks as seen from many different birds. In it he clarifies the perils of anthropomorphizing. Birds are very good at being birds and they do not do avian things in a manner that we might do them should we be able to fly and nest and all. They have their own natural agenda.

When we watch birds especially this time of year as mating instincts kick into gear, we often see the male and female together. In a short while we may see some males feeding and otherwise appearing to be affectionate with the mother of its chicks. Some birds mate for life…or so it seems. Heinrich distinguishes between biological mating and social mating. Birds are not nearly as faithful as it appears and the author suggests many advantages to polyandry and polygyny.

He also discusses the courtship rituals largely from the males and the costs of such behavior. All that bright plumage and highly stylized lekking also marks the male for predation should he be less prudent. With success in selecting mates, neurological changes occur. Nest building we are told, inspires hormones needed to prepare for the egg fertilization and the rearing of the chicks. The nests themselves are very particular to the species. Some are very efficient and others more ornate. John Burroughs wrote over one hundred years ago about the changes in nesting behavior that came with closer proximity to humans. Once again at a cost.

Cuckoos and cowbirds drop their noisy progeny into the nests of other birds who get stuck with the feeding and rearing bills at the peril of their own offspring. The loudest infantile cheeping garners the most food.  Then there is the rearing of the young. Some birds are precocial meaning that they can perform many functions of adults immediately. Mallards for instance swim and feed themselves upon emerging from the egg. Yellow crown night herons which I observe, are altricial meaning that like humans they are pretty much helpless at birth. Some birds grow to adulthood quickly and others such as ravens do not mate for several years. The ravens stay near to their (social) parents for several years both helping and training for their own future.

The book is rife with information about our avian friends and Heinrich describes activities and behaviors in a way the avid amateur can understand. He also makes several points about nature and evolution along the way that helps understand how birds work.

Birds have no plan. They have instinctual responses as seen in mating behavior and they have many levels of learning as the author has pointed out in some of his other works. What they do most is select mates that have shown vigor by their coloration, birdsong, nest building and place in the pecking order. They have spent much effort on the process of mating, breeding, nesting and raising chicks to fledge. In some cases there is even post fledge costs and benefits. They do not do any of this for our benefit but all for the continuation of their species.

There is always incredible depth to a Heinrich book; far more than can be reflected in a review. I hope he lives to be 1000 so that I will always have a new book to read.

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