Summer World: A Season of Bounty – Bernd Heinrich, 2009

Read for Nature and Environment. We liked it, although not as much as Winter World – it’s not as focused; it rambles all over the map. It’s a beautifully designed book, with green print on cream paper, but not quite enough contrast for easy reading.


The possibility of individual caterpillars to generate amazingly different forms makes me appreciate what is possible in the debate over nature versus nurture. Much of what we are and become depends on minute subtleties, and that gives me hope in the reality of free will, and its power if we choose to exert it.

The sugar borers have achieved, or are held to, something enviable. They are in a world of plenty, so none go hungry, destroy their habitat, or jostle and interfere with each other. Somewhere there is a check on their natural rate of increase, and you can be sure of one thing—that if they could tell us what they wanted at any one time, they would vote to obliterate the forces that hold them in check, the forces that ensure their long-term benefits. And so, probably, would we, if we voted merely on the basis of our individual interests.

We can still compete with cheetahs, lions, and leopards in running down antelope, but we can do it only in the midday heat. And the reason is that we have the mental capacity to pursue a goal that we can neither see nor smell but that we can imagine. Additionally we have a unique suite of adaptation to deal with internally generated body heat under the blazing sun. They include our nakedness, our ability to route blood to the surface of our extremities so that our veins bulge at the surface of exposed skin, and our ability to sweat profusely over the skin. These are capacities needed by hunters who get their edge through endurance in the heat.

In this book I learned

  • Reason for separate leaf/flower buds (which I learned to distinguish when doing spring observation of “Order of Bloom” at the Botanic Garden): strategic time-wise separation, for example wind-pollinated before leaves, bee-pollinated in late summer when insect activity is peaking
  • Woodfrogs “often freeze solid, and in that condition they don’t have a heartbeat, breathing, digestion, or activity of the brain cells. A reputable human pathologist … would conclude that they are dead.”
  • Red-eyed vireos decorate their nests with bits of hornet nests – not as insulation, not structural, and “hornet paper is hard to come by.” Heinrich theorizes maybe it deters squirrels (e.g.) from approaching the nest?
  • Additionally, he says wood thrushes incorporate snake skin, catbirds line their nests with rootlets and decorate with grape bark, and ravens and chickadees use fur – no speculation as to why.
  • In his studies of bumblebees, Heinrich found that individual bees became specialists in particular flowers – “they developed ‘search images’ of what flowers to look for.”
  • Some caterpillars eat leaves selectively so they look the same but smaller (rather than full of holes) – to avoid giving away their presence
  • Longhorn beetles can detect tree injury – “when I chop down a pine, fir, or spruce, one group of these beetles, the sawyers, Monochamus, come flying in—within minutes!”
  • Before flower nectar is available, hummingbirds rely on the insects that yellow-bellied sapsuckers draw to their weep holes
  • “We breed ’em, you feed ’em” — bumper sticker of the Maine Blackfly Breeders Association
  • “Sand grouse in Africa have special feathers on the breast that soak up water so that it can be easily carried back to the nest. The young sip the water from the tips of the feathers, like baby mammals suckling on their mother’s teats.”
  • Cicadas are active when it’s too hot for their predator, cooling themselves with the equivalent of sweat glands.
  • Welwitschia – I love visiting the big one at Smith Botanic Garden!
  • “Perpetual summer species” – long-distance migrating birds. “They can always live in a summer world, thanks to energy-rich berries and heroic sustained exercise. … We manage the same trick of living in perpetual summer, although not by strenuous biannual migrations but by creating and retreating into ‘climate bubbles.'”
  • Heinrich claims humans are unique because we have 3 species of lice (head, body, pubic) and no other bird or mammal does. Really??? Is it possible they just haven’t been looked at closely enough? Why would that be? It only took a minute of searching to find that great apes in general have lice of both Pediculus and Pthirus genera, so I’m a little disappointed in the scholarship there.
  • “We still [post-DDT] release about fifty new chemicals into circulation per week. They are tested on lab rats—animals that never experience summer or winter, that live in dumps, and that when tested have no relation to any ecosystem except a sterile cubic plastic box.”
  • Some tree species “time their blooming by not blooming, and thereby control the seed predator population.”
  • “What we observe now is a result of evolution over hundreds of millions of years. But the selective pressures that have acted on some features in the past are now unlikely to occur every year and may be seen only rarely. Instead, they are probably witnessed only at bottlenecks.” That’s like what Beak of the Finch described.
  • I compared notes with my book group on Heinrich claiming he didn’t know rhododendrons rolled their leaves in the cold until he read it in a 2007 paper about rhodys in the mountains of northern China. “I could not believe my eyes when I saw the leaves of rhododendron of two species planted on our campus also rolling up.” We all knew that from first-hand observation. Plant blindness?

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