Brainy
Their brains may be tiny, but that doesn’t prevent birds from being smart. They just pack more brain cells into a smaller space. A team of research scientists counted the number of neurons in the brains of 28 different bird species of all shapes and sizes. “They found that birds have higher neuron counts in their small brains than do mammals or even primates of similar brain size. . . . This tight arrangement of neurons makes for efficient high-speed sensory and nervous systems. In other words . . . bird brains have the potential to provide much higher cognitive clout per pound than do mammalian brains.”
Talkative
Much of the early bird research focused on migratory songbirds in the northern hemisphere, leading us to believe that only male birds sing, primarily to attract a mate. That has proven to be a very incomplete view of avian communication. Approximately 16% of birds, primarily in the tropics, perform male-female duets. What at first take appears to be the song of an individual bird turns out to be a rapid-fire call and response from a male and a female bird: “So impeccable is their timing that canebrake [wrens] answer their mates within sixty milliseconds, around a quarter of the time it takes for a human to chat back.”
In an Australian park, a tiny spotted pardolate warns his neighbours – both avian and mammal – of danger. The calls often change to indicate different kinds of danger. There are mobbing calls inviting other birds to help chase away a predator and alarm calls urging birds to flee and avoid a threat. The calls can convey detailed information: Is danger from above or below? Is it moving fast or slow? “The chickadee-dee-dee mobbing alarms calls of the black-capped chickadees contain messages – coded in the number of dees at the end of the call – about the size of the predator, and hence, the degree of threat it represents. A great horned owl, too big and clumsy to pose much of a risk to the tiny chickadee, elicits only a few dees, while a small, agile bird of prey such as a merlin or a northern pygmy owl may draw a long string of up to twelve dees.”
Piping plovers will pretend to have a broken wing to draw predators away from their nest, while quails will pretend to be dead. Scrub jays will move – or pretend to move – their food stashes if they know they’re being watched.
Birds are also amazing mimics. Lyrebirds can sound like dogs barking, the blows of an axe, the hooves of a trotting horse, as well as the calls of other birds. And they switch between sounds quickly: “Two seconds of eastern whipbird, then two seconds of crimson rosella, followed by three seconds of grey shrike thrush.”
It isn’t easy to imitate a song. You must listen closely, memorize, recall, and practice, adapting your vocal muscles to replicate the song of a different species. So why go to all that effort? It may be to impress a potential mate, but it may also be to deceive and manipulate. There are reports of blue jays mimicking red-tailed hawks and other raptors to startle other birds into dropping their food and providing the jay with a free lunch. Burrowing owls imitate a rattlesnake to stop ground squirrels and other competitors from stealing their burrows.
A Different Way of Knowing
The wedge-tailed eagle can see 3 or 4 times further than a human with extra magnification in the centre of its field of view to focus on its prey. Birds also experience an extra dimension of colour as they are able to detect ultraviolet wavelengths. The dense foliage of the rainforest is uniform and flat to human eyes. Not so for birds. “UV light amplifies the contrast between the tops of leaf surfaces and their undersides, so the three-dimensional structure – the position and orientation – of the leaves pop out. This makes it easier for birds to navigate through complex leafy environments and to find food there.”
Similarly, to humans the ocean appears vast and undifferentiated. But not to seabirds for whom it’s “an elaborate landscape of eddying odor plumes that reflect the oceanographic features and physical processes where phytoplankton predictably amass.”
Let’s Play!
Birds love to play. Warblers and pelicans throw pebbles, while green herons toss sticks, leaves, and fish into the air. Rainbow lorikeets swing from tree limbs, while Arabian babblers wrestle and play tug of war and king of the hill. Birds that engage in social play where they interact with each other have a complex social system. Ravens are particularly prone to playing and it starts when they are still in the nest. Play may be preparation for later life. Investigating different objects helps young ravens distinguish what is safe from what is dangerous, while manipulating objects may help them develop their caching skills. Playing together may also promote social bonds, teaching animals how to interact and establishing a hierarchy.
There is no one way to be an avian parent. The brush turkey male works very hard maintaining a huge pile of garden debris, checking the temperature of the fermenting vegetation on a daily basis to make sure it’s at just the right temperature to incubate the eggs buried inside the pile. He also pays attention to the weather, piling the mound up high to help rain to run off and opening the pile up to dry out once the rain stops.
Leaving your eggs in another bird’s nest may look like the lazy bird approach to parenting, but that’s not necessarily true. Female brood parasites are very picky when choosing nest sites. They want experienced parents with a proven track record and solid nests. Egg laying must coincide with when the host bird is laying her eggs, and eggs must be laid very, very quickly. Each egg is laid in a separate nest so she has to memorize where the nests are located and which ones she’s already used.
Seers and Omens
Jennifer Ackerman concludes The Bird Way by a reminder that in ancient Rome “bird-seers were priests, or augurs, who founded their divinations on the flight patterns of birds.” She goes on to suggest that we “would do well to watch birds more, tune in to their usual and unusual behaviors, learn while we can from their marvelous – and still often mysterious – ways of being.”
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