Not being Australian, I don't think I am in the core audience for this book. Nonetheless, I found it fascinating. While he dives into the details, especially in the second half of the book, Low always tries to give a wide perspective. I like that he tries to explain why Australian birds are different, the evolutionary reasons. (Of course these speculative explanations could be wrong, but they are still interesting to consider.) I would have preferred to have more anecdotal stories from Low himself about his interactions with birds, or with bird science. He includes a few such stories, but they are very brief and not particularly interesting.
> Twenty million years ago Australia was wetter and largely clad in rainforest. For much of its past it was united with Antarctica by a peninsula of land that gradually narrowed and was finally severed some 45–38 million years ago. … The continent slowly dried as it wandered north, 7–8 centimetres a year, into the dry middle latitudes. … From 100,000 years to about 11,000 years ago it would have been possible to hike 5000 kilometres from northern New Guinea all the way to southern Tasmania.
> One book on the subject expressed the general view that no bird-pollinated flowers exist in Europe, nor in Asia north of the Himalayas. That was proved wrong by a 2005 article, "First Confirmation of a Native Bird-pollinated Plant in Europe," when warblers were seen on rare pea flowers in Spain, but the pool of examples remains ridiculously small. The contrast with Australia could hardly be greater. Many of its best known plants are bird-pollinated: banksias, grevilleas, bottlebrushes, grasstrees, paperbarks, hakeas and hundreds of eucalypts. Birds are not the only visitors of these flowers but often serve as their best pollinators.
> Nectar birds are plentiful in Africa, the Americas and tropical Asia, but the vast majority are tiny hummingbirds and sunbirds. … Australia's biggest honeyeater – the Tasmanian yellow wattlebird – is five times the weight of the largest nectar bird on another continent, the spectacled spiderhunter of South-East Asia, a large sunbird.
> Australia's ample sunshine and depleted soils encourage plants to produce more carbohydrates than they can use. All the sugars produced by photosynthesis cannot be converted into tissues or seeds because the soil nutrients needed as additional ingredients are scarce. The surplus sugar is fed to birds as nectar in return for pollination. Birds can thrive on this sugar because they eat insects as well to provide missing nutrients. Honeyeaters will pursue flies so tiny that more energy is lost chasing them than is gained eating them, but they have bountiful sugar to fund their pursuit of rare phosphorus, zinc, iodine and cobalt. These minerals have become precious because Australia is so flat and geologically stable that there is little new soil created to replace the nutrients leached away by tens of millions of years of rain.
> The large landmasses in the north accumulated so much ice that plants had to relocate to survive. In the Southern Hemisphere, oceans moderated temperatures by carrying warm water south and persistence in situ was often possible. Australia is so infertile that many plants succeed by adapting to certain soils, reducing the value of migration because the soils vary so much from region to region. A strong flowering effort reduces the need to move by assisting genetic turnover in times of change.
> The Sydney region alone has more than twice as many eucalypt species (100-plus) as Britain has total tree species.
> Wind-pollinated trees cannot mingle like this because too much pollen reaches the wrong stigmas. … A large pool of trees can sustain a large community of birds if flowering across a region is staggered to provide continuity. Bird pollination benefits from diverse forests in a way wind pollination does not. … The presence of the honey possum, the world's only non-flying flower mammal, one that depends entirely on pollen for protein, attests to nonstop nectar for millions of years past.
> Parrots may account for the difference in accessibility, since their beak shape means they can't get nectar from tubes unless they tear open and ruin flowers. I suspect that, to limit damage from parrots, Australian flowers evolved readily accessible nectar, and this liberated honeyeaters from the need for specialised bills.
> Honeydew shows up mainly in cool places, perhaps because sugar plays a role as antifreeze in sap. … Cider gums are Australia’s most cold-adapted trees, with sap that thickens into a honey-like syrup you can lick from the tree. In the Northern Hemisphere, maple sap only becomes sweet when it is boiled down to syrup.
> Of the three groups of birds that learn rather than inherit their calls – songbirds, parrots and hummingbirds – the first two count as the most intelligent of birds, some proving better at problem solving than most mammals. … From what we currently know, a capacity for vocal learning has evolved eight times, the other occasions being among humans, elephants, seals, dolphins and whales, and some bats.
> Parrots have a discerning palette, with somewhere between 300 and 400 taste buds, more than chickens (250–350) and many more than pigeons (37–75) and bullfinches (46), though far fewer than humans (9000) and catfish (100 000).
> To conserve scarce nutrients in the highly infertile soils, plants produce long-lasting leaves, protected from herbivores by high levels of fibre and often tainted with aromatic oils and phenolics. These defences are cheap for plants to produce because the key ingredient is carbon fixed during photosynthesis, rather than, as in most toxins, scarce nitrogen extracted from the soil. The oils and lignin in these sclerophyll plants, as they are called, burn readily, resulting in leaves that are often flammable when green. Orians and Milewski stressed that plants are flammable where soils are poor
> Australia has ten times as many pigeon genera as Europe, and twice as many as North and South America combined (they have ten altogether to Australia's twenty).
> Seabird wings, being long and thin for soaring, have reduced value for lift. An albatross on land cannot explode into flight like a startled pigeon; it must leap or lean into turbulence, or lumber along the ground flapping. No albatross or shearwater ever pulled up gracefully in a tree, as their wings have poor braking power and their paddle feet lack a toe for grip. All petrels nest on or under the ground, never up in trees, obliging them to find islands without mammals. … Because its chicks, on their maiden flight, need a long drop to engage their wings, Abbott's booby is the only seabird anywhere to need tall rainforest.