The Birds at my Table

by Darryl Jones

  The BSA standards also list a series of items that are “Nil Allow-able”: “ingredients that are not permitted in mixes displaying the BSA logo.”58 These banned items are large striped sunflowers, whole peanuts, biscuit, extruded dried pellets, all seasoned/spiced/salted ingredients, len-tils, whole pulses, vetch, whole maize, flaked barley, dried rice, split peas, and barley. Other authorities have produced similar “not-to-be-used” lists that include avocado, chocolate, fruit pits, persimmons, onions, and mushrooms. I am sure there are plenty of others too. The issue here is that many of these food items are actually things people eat and are therefore readily available in the cupboard or fridge. These things are familiar and convenient—and easy to add to the bird’s menu. The birds at our tables are, after all, welcome guests. Why not share our all our food?

  Sharing food might sometimes be a significant problem. Provocatively, New York writer Jim Sterba regards the recent transition (through clever marketing) of our companion animals from simple pets to pampered family members as similar to the evocation of wild birds as “outdoor pets” by the birdseed companies.59 The next step is obvious. Sterba’s point is that if feeding chickadees is fine, why not raccoons or groundhogs—or bears? His argument is heading away from my current theme (but can be followed in Sterba’s eye-opening book, Nature Wars,60 though don’t expect subtlety) but does return us to the important issue of our responsibilities as provisioners to wild visitors. Birds certainly consume all manner of items they find, at feeding stations or elsewhere, but that does not mean that they should. The list of forbidden items provided above is based, in part at least (some of the items are just too big and could result in choking), on nutritional standards or components genuinely harmful to birds. In many cases, most birds are unlikely to consume enough of such items to be of serious concern. Some things, however, are a real worry. Anything with salt, for example, should definitely be avoided.

  Possibly the most commonplace human food supplied to wild birds globally is bread. It seems that every pond in every park in the known universe experiences the phenomenon of duck feeding, typically involving many, many slices of bread, almost daily. This is a traditional, cross- cultural, immensely popular, and worldwide interaction of humans and wildlife worthy of an entire book in itself. While the feeding of birds in gardens has now started to be the subject of serious research, we still know almost nothing about almost every aspect of duck feeding. Most crucially, despite plenty of concerns, claims, and rumors about the impact of all that bread, remarkably little can be stated reliably. Probably the most attention has been paid to ecological implications of the massive inputs of bread on the functioning of closed lake ecosystems. For example, several studies have described eutrophication and alarming levels of phosphorus in urban ponds with lots of duck feeding.61 About the ducks themselves, however, virtually nothing.62

  Closer to home, bread is a very common component of many garden menus. But while some promote its use, many authorities warn against it.63 Most agree that bread provides little nutritional value and may actually ex-acerbate malnutrition by filling the birds with low-quality ballast. It would be nice to be definitive, but the reality is that we just don’t know what effect a bread-heavy diet might have on the health and well-being of birds.

  Is Meat a Meal?

  Although somewhat unusual globally, the provisioning of meat for garden birds is quite typical in Australia, where large omnivorous species such as Australian Magpies, butcherbirds, and Laughing Kookaburra are favorite visitors to feeding stations.64 All sorts of human foods are offered to these species—cheese, bread, rice, pasta, leftovers—but it is the various types of meat that are preferred (as described in Chapter 5). Thankfully, some aspects of this practice have been studied. Investigations of the blood chemistry of experimentally fed magpies found that birds consuming substantial amounts of minced meat (ground beef) or “dog sausage” (moist pet food), two commonly used feeder items, found significant increases in plasma cholesterol and fatty acids.65 Although the health and condition of these birds appeared to be identical to unfed magpies, there are well-established physiological impacts of a prolonged fat-rich diet, including impaired liver function.

  More alarmingly, however, is the possibility that birds consuming large amounts of what is usually straight beef meat may become susceptible to the calcium/phosphorus imbalance mentioned above. Beef contains about 0.01% calcium compared to 0.19% phosphorus, with a ratio of around 1:17. Were such food to dominate the diet, there is a significant chance of the birds suffering from a pathological condition known as nutritional secondary hyperparathyroidism.66 This is associated with an inability to absorb calcium and often results in thinning of the bones (as the body seeks a supply of the mineral it can no longer obtain through ingested food) and a range of skeletal and physiological malfunctions. This particular condition is best known from captive parrots with diet limited to sunflower seeds, peanuts, and oats (calcium:phosphorus ratio of 1:10) but is also familiar to zookeepers responsible for carnivorous species such as birds of prey. Rather than feeding these birds raw meat, most zoos now include whole animals, or add skin, bone, and fur, to help balance the crucial Ca:P ratio. It is also a key reason that the guidelines for the private feeding of reintroduced Red Kites in English gardens (as described in Chapter 4) suggests that whole animals be offered rather than just meat.67

  Concerns about the possible implications of the vast number of Australian Magpies partaking daily of the protein-rich, calcium-poor beef mince offered throughout the country were reduced when our studies showed that feeder foods made up only a small proportion of their diets.68 Even when numerous feeding stations piled high with the stuff were just a few blocks away, most suburban magpies continued to dig up worms and grubs as they always had. Making this discovery—some time ago now— was genuinely welcome news. Confirming that at least one species that we had expected was likely to forsake natural foraging but did not was greatly reassuring. There was also some relief in finding that these birds retained their diverse diet and were not simply focused on the easy-to-find junk food option. At the time I was not aware of the potential risks associated with meat-heavy diets, so these more recent revelations about the possible implications of having a grossly unbalanced calcium:phosphorus intake was something to be reconsidered carefully. Returning to our data showed that many recently independent magpies, experiencing the realities of life away from the home territory, often congregated in numbers at some of the more generous feeding stations. These were often located in constricted gardens, typically hemmed in by hostile territorial male magpies, but represented safe havens and a source of plentiful food. Most suburbs seemed to have such sanctuaries, filled with high numbers of nervous teenage magpies, and always centered on a well-used feeding platform. Understandably, the people involved, confronted with a persistent but obvious appreciative cliental, typically respond with ever-greater piles of mince. These are the very circumstances in which the problems associated with a meat-rich—maybe even a meat-only—diet could very well be a serious problem. Whether this is the case has yet to be confirmed. What is somewhat reassuring is that these dense concentrations of magpies do not last forever. Most individuals seem to find a mate and eventually leave in search of their own patch elsewhere. And resort to the natural diverse diet of sensible grown-up magpies. I hope.

  And just when you think you have seen it all, or at least been sent the YouTube clip, something entirely unexpected turns up. A journalist friend of mine, Matt Watson, recently e-mailed me a single photograph accompanied by a disconcertingly simple question: “What do you think about this?” The image had an unremarkable setting (for an Australian backyard): a typical magpie feeding station with a sizeable mound of beef. There was one glaring anomaly: the birds perched atop the pile of meat and clearly partaking with enthusiasm, gobs of mince smearing their faces, were Rainbow Lorikeets, the abundant and familiar parrots that visit my own feeder every day. To see this species, one I thought I knew reasonably we
ll, clearly eating meat was really unsettling.

  Although it started out as one of those animal curiosity pieces at the back of an online edition, the story of the meat-eating parrots rapidly acquired a virtual life of its own. Once it hit the big international outlets, especially the ultracool science website IFLS (Vegetarian Birds Turns Carnivorous! ), it reached a vast audience, spawning plenty of great head-lines of course (including Piranhakeets).69 When I collated the locations and considered the over 500 completely unsolicited e-mails I subsequently received, it was obvious that this phenomenon was both common and widespread.

  This provided an opportunity to investigate a completely new bird-feeding phenomenon, and I soon contacted the e-mail senders to invite them to provide more details. While this research obviously has a long way to go, a number of significant aspects have already begun to emerge. First, and very surprisingly, it has become clear that meat eating is not at all unusual among lorikeets, or, indeed, a long list of other parrots. A large number of people described pet parrots of many species being strongly attracted to meat, with tales of free-roaming birds joining the family to chew on roast dinners or steal chicken bones from plates. While a modest number of species were reported feeding on meat at feeding stations, many more were mentioned feeding on meat in the wild, usually road kill or dead farm animals. While this certainly seems bizarre, we soon discovered that almost all parrots, including those apparently specializing in nectar, pollen, and fruit, also actively seek animal food in the form of insect pupae and grubs, especially those infesting flowers and fruit.

  The picture that is slowly emerging is one of birds that have always sought animal protein to add to their diet, and have done so opportunistically whenever the chance arose: insects encountered during normal foraging, a dead animal, or the discovery of an infestation of wood beetles, for example. Generally, such bonanzas will be fairly rare, unpredictable, and short-lived. Adding protein to a plant-dominated diet is essential for regular nutrition. Having access to such a typically unpredictable resource—such as a feeding station laden with fresh raw meat every day— was simply never part of the picture. But it sure is now. And at least some of these birds are making the most of it, feeding in a manner that suggests that their meat intake is dominating their daily diet. If so, this could be genuinely serious.

  The material gathered in the development of this chapter has often been unexpected, alarming, and, frankly, depressing. But it is an essential and unavoidable part of the story. The act of feeding birds can have serious consequences. Some of the risks are now clear. But feeding can also be profoundly important, actually playing a role in preventing extinction. To consider this aspect of bird feeding, let’s head far, far south.

  7

  FEEDING FOR A PURPOSE

  Supplementary Feeding as Conservation

  It’s a long way to New Zealand from just about everywhere, though thankfully, not from Australia. For such a remote and relatively small collection of islands almost at the bottom of the planet, its place in the minds of birders and conservationists is distinctive and rightly celebrated. Tales of the decidedly odd kiwi, sheep-eating parrots (Kea), and those gigantic though extinct moa are more than enough to fire the imagination of any keen naturalist.1 All too often, however, the reality for visitors seeking to encounter the remarkable endemic birdlife of Aotearoa (the increasingly used Maori name for the country) is typically disappointing. Since the arrival of humans, first the Polynesians and, more recently, the European settlers have been extraordinarily successful in transforming a land of dense, dark forests into an almost exact replica of genteel rural England. And that includes thriving populations of European birds, many declining or rare in the UK and Europe. Wander through the delightful parklands in Auckland, Wellington, or Christchurch and Chaffinches, Song Thrushes, and Greenfinches are everywhere. Set up a feeding station—as demonstrated so clearly by Josie Galbraith—and it will soon be swarming with House Sparrows, Blackbirds, and Starlings.2

  But where are the native species? Certainly, some are there in the gardens and parks as well—small ones such as Silvereye (or White-eye), Tui (a vibrant, vocal honeyeater), and Grey Warbler—and even larger birds such as Kererū (the huge fruit- and leaf-eating New Zealand pigeon) and Kākā (a close relative of the Kea parrot of the mountains) are increasingly being seen in towns and cities, a direct result of habitat restoration and, to some extent, garden feeding. But these successes are limited though welcome exceptions to the conservation status of many New Zealand birds. Despite the extraordinary efforts of many passionate New Zealanders, their birds are in serious trouble. There is no mystery to this terrible state of affairs. Starting with the arrival of the first humans only about 800 years ago, several devastatingly effective processes were unleashed: the mass clearing of the dense temperate forests, unusually efficient hunting by people, and the impact of the mammalian predators that accompanied them. The destruction of huge swaths of forest and the rapid extermi-nation of the nine species of moa by the Polynesian predecessors of the modern-day Maori are disturbingly well understood; these were events that occurred relatively recently, allowing researchers to piece the puzzle together all too well.3 After all, New Zealand was the last major land-mass on earth to be colonized by people, allowing the waves of calamity to be mapped and dated with alarming precision. Until around the 13th century—a time when King Edward I reigned in England and the Mongols were raiding central Europe—these mist-shrouded islands, stretching for 1200 kilometers (745 miles) across the cold southern ocean, remained unknown to humanity. Their remoteness and isolation from all other lands allowed a remarkable community of animals and plants unlike anywhere else to evolve, most significantly because an entire major component of the vertebrates was missing. When the bits of land that were to become New Zealand split off from the original supercontinent of Gondwana, there were no mammals onboard. As a result, over the following 80 million years, these islands became the land of birds, diversifying into around 200 species and occupying every possible niche from the dark floor of the dense podocarp forests to the tops of the soaring snowy mountaintops.4 There were minute wrens seeking insects along the coastal beaches, formidable Adzebills (a huge rail) striding through forests, and, of course, all those moa, ranging from goose-sized to the towering Giant Moa that could stretch its neck to over 3 meters (10 feet) in height, taller than any other bird. Remarkably—and very significantly—a large proportion of the land birds of New Zealand became flightless.

  This propensity for New Zealand’s birds to stay on the ground instead of flying was not simply because there were no predators. The broad diversity of lifestyles that evolved included plenty of carnivorous species including those Adzebills and Haast’s Eagle, the largest bird of prey in the world.5 Some of the moa were also predatory, but it appears that for most birds, running, hiding, or freezing were the best means of survival. Avian predators tend to be visual, relying on movement to detect their prey. Mammals, in contrast, smell out their potential meals. You can tell where this story is heading.

  When those first waka (the massive Polynesian ocean-going canoes) crunched onto the pebble beaches of the northern extremities of New Zealand,6 it was not only the stone axes, firebrands, and hunting spears accompanying the people who disembarked (into what would have been a bewilderingly different world) that were to utterly transform this land. Also aboard, either as typical ship-dwelling vermin or possibly as fresh meat for the long voyage, were Kiore, the Polynesian rat, a species found throughout the islands of the Pacific.7 Their first encounter between a New Zealand bird—say a North Island Snipe wandering along the nearby dunes—would have been predictably brief and fatal. The complete lack of fear the bird would have probably shown, frequently reported as innate stupidity or beguiling innocence, is better explained by the mammal-free eons of isolation. Nothing had prepared them for the fur-bearing catastrophe that was about to engulf them. As is continuing to happen today, the bird would have simply stopped where it was, trusting
in its camouflaged plumage. The Kiore is only a relatively modest-sized rat (40–80 grams [1–3 ounces]), but it appears to have wiped out or greatly reduced many of the land birds within a remarkably brief time.8 Perhaps most significantly for the overall ecology of the country, the rats appear to have ravaged massive colonies of ground-burrowing petrels, forcing entire populations to abandon traditional breeding grounds and relocate to offshore islands. According to recent analyses, the sudden cessation of millennia of guano production by unimaginable numbers of seabirds would have had enormous and long-term consequences for the fertility of vast areas downhill of the colonies.9 It seems hardly possible, but the arrival of a small rodent hundreds of years previously would profoundly influence agricultural production in the future.

  While the work of the kiore would have happened unseen in burrows and in the dark of night, the ruthless efficiency of the daytime Maori moa hunters was proceeding apace. Again, it appears that the lack of fear of humans made the moa pathetically easy to hunt and kill, at least until inevitably they became harder to find. Enormous butcheries consisting of the bones of vast numbers of moa attest to the scale of the bonanza; one site alone (Shag River on the South Island) accounted for over 6000 individuals.10 Of course, such protein riches were not to last; some authorities have suggested that moa meat fueled considerable growth among the Polynesian populations and that the collapse of this resource had major consequences for Maori society and culture.11 While the social implications of these events continue to be debated, the ecological impact of the rapid loss of what would have probably been the most influential players in the complex bird community can only be guessed at.