Essays of INTEREST
INTELLIGENT BIRDS
If one needs more evidence as to why I think that the corvids are the smartest birds on the planet, you need not listen to anything else after this.
The corvids, of course, refer to the collective assembly of birds which include ravens, crows, jays and magpies.
In this latest example of uncanny intelligence where birds outsmart humans, it is the Australian magpie from ‘Down Under’ that shines this time. This generalist species not only excels in problem-solving but has adapted well to the extreme changes to their habitat caused by humans. Moreover, they generally live in social groups of between two and 12 individuals, and even breed cooperatively, with older siblings helping to raise young. The victims in this amazing story were Dominique Potvin of the University of the Sunshine Coast, and her research colleagues who just published a paper on these birds in the scientific journal, Australian Field Ornithology.
The goals of their study were two-fold: first, to learn more about the movements and social dynamics of Australian magpies by attaching tiny, backpack-like devices to just five birds as part of a pilot study. And second, to evaluate the durable and reusable tracking devices which were new on the market and weighed less than a gram as well as the special harness devised to affix them to the birds.
The general idea was to use a transmitter to acquire the tracking data, be recharged as needed, and even removed by releasing a magnet, all without recapturing the birds. In other words, remotely. To achieve these actions, the research team trained the wild magpies to come to an outdoor, ground-feeding station. After affixing the transmitters to the five birds, the scientists got quite a surprise! Within ten minutes of putting on the final tracker, an adult female not wearing a tracker used her bill to try and remove the harness from a younger bird. Just a few hours later, almost all of the trackers had been removed, with the final dominant male having his removed by Day 3. It is not known if it was just one individual “rescuing” all of the other birds from the unwanted tracking devices or if the behaviour was shared. Regardless, the important message is that the birds actually needed to problem-solve by pulling and snipping at different sections of the harness with their bills. Most important, they needed to willingly help other individuals of their species, and of course, accept help too. So, it is back to the drawing board for Potvin and her team.
BIRDS HELPING EACH OTHER
Meanwhile, this is not the first time that a magpie species has shown interest in helping other members of their own kind.
Back in 2021, I wrote about a laboratory study of captive azure-winged magpies conducted by Jorg Massen of Utrecht University and colleagues from other European institutions.
They discovered that birds with plentiful amounts of mealworms were not only willing to share their bounty among their own kind, but they were also able to discern whether the recipients had need of the food.
In other words, they were demonstrating sympathy with the less fortunate individuals whether the latter begged for food or not. It will be interesting to see if this trait, which is known as prosocial behavior, will turn up among not only members of the highly evolved corvid family but other bird groups as well.
SMELL IN HUMMINGBIRDS
Speaking of
amazing new discoveries about birds recently,
we have always known that hummingbirds use visual cues to locate flowers and collect their nectar. And they can even use their incredible spatial memories to remember what flowers they have visited.
But who would have thought that they also use smell?!
Ashley Kim and her co-investigators at the University of California at Riverside decided to put this to the test by offering over 100 hummingbirds a choice between two feeders, one with just sugar water and another with added scents indicating the presence of certain insects. You see, bees, wasps and ants not only drain the nectar in flowers they visit, they can also repel hummingbirds from flowers they occupy. Wasps physically chase them off, whereas ants deposit irritating formic acid. Because these creatures sometimes deposit chemical cues during foraging and agonistic interactions, the researchers wanted to find out if bees use smell as part of their procedure to avoid wasting time on flowers already visited by other nectar-seekers or worse, being physically repelled by competitors.
The results were interesting. Publishing in the journal, Behavioral Ecology and Sociobiology, Kim and her team found that their hummingbirds did indeed avoid flowers with the scent of two kinds of ants, but not less harmful honeybees. But would that mean that hummingbirds would also avoid sugar water feeders if wasps and/or ants had left chemical cues on them? While the scientists did not test that hypothesis, I am guessing that the hummers will not avoid them for several reasons.
First, I am not sure that wasps and ants can leave chemical cues on a smooth plastic feeder.
Second, unlike flowers, feeders are only limited in the nectar they supply by how often we fill them. Third, I do not believe that hummingbirds use the same foraging strategies with our feeders. If the wasps and ants are not present on a given feeder, that should mean open season for any hummingbird.
WHO DOES NOT LOVE THE SONG OF A BIRD?
Recent studies have told us that being surrounded by singing birds in one’s environment can make us happier, healthier and even live longer. But would you feel the same way if the source of that song was from a bird in a cage?
Well, some people out there in the world do.
According to a recent study, bird-singing contests are now a major driver in the global songbird trade. Contests take place in no less than nineteen countries but are most prevalent in Southeast Asia.
This is not a new phenomenon, folks!
For thousands of years, people have been keeping wild birds and it is often deeply ingrained in certain cultures. And as far back as the 14th century, India, Japan and China held bird-singing contests.
While most birds can be bought in a market for just a few bucks, the most accomplished birds, the ones with the most stamina, can sell for as much as $15,000 U.S.! No surprise either, considering that the prize money for some contests, such as the President’s Cup in Indonesia, can go as high as $80,000 U.S.
Contests usually start at seven in the morning before it gets too hot. Each competition lasts about 10 to 15 minutes and the judges decide the winners based on a combination of songs, plumage and movement. Winning these contests is not just about money either --- family pride comes into it.
One chap in Suriname keeps no less than 200 singing birds in his house, much to the chagrin of his wife.
From a conservation point of view, these contests are not a good thing. While some birds are captive-bred, many are live-trapped.
The white-rumped shama, brown-headed barbet, and the orange-headed thrush are among the top five most popular species for singing contests and all three of them have declining populations.
As if the birds on our planet did not have enough to worry about!
Readers OBSERVATIONS
GREGORY WEIL, a dear friend of mine and a keen observer of nature, owns a lakefront home on Lac St. Louis in Baie d’Urfe, Quebec. The marsh in front of his home is often frequented by various species of waterfowl. Recently, he noticed that a pair of mallards was spending an inordinate amount of time in and around a fair-sized cavity in a large silver maple in his yard. He was curious to know whether mallard ducks ever nest in trees.
COMMENT
Your question about whether mallards nest in trees is an intriguing one, if only because one usually associates a duck with nesting on the ground somewhere. But there are several species of ducks that do nest in holes in trees; some examples include goldeneye, mergansers, buffleheads and wood ducks. In fact, some of those species will readily use nesting boxes if placed in the right habitats. Back to your mallards though. The vast majority of pairs of this species, both in rural and urban areas, are most likely to make their bowl-like nests, ringed by vegetation and even breast down, on the ground near water and under dense cover for concealment against raccoons, coyotes and foxes. Since mallard ducks are ubiquitous and found all over North America, their preferred habitat will vary with what is available.
Some of the more favored cover plants include reed grass, bulrushes, cattails, sedges and various kind of grasses under a meter high. But mallards are also known to nest in dead treetops, large hollowed out cavities and even in abandoned raptor or crow nests. I suspect that those two large silver maples in your backyard along the river shoreline likely harbour some sort of large, easily accessible rotted out holes in their crotches and the ducks have got their eye on them as a potential nesting site. Which begs a question - how will their ducklings fledge from the nest? Probably in the same fashion as wood duck babies from a nest hole high up in a tree. They have been known to leap from heights up to 65 feet and because they are so light, they just bounce off the vegetation, totally unharmed. I am sure that mallard ducklings can do the same.
GEORGE GILCHRIST, an avid feeder of birds in Hamilton, Ontario, lost not one but two downy woodpeckers to hawks in just one week. A month before that, a hairy woodpecker had been killed in the same way. Observing no similar attacks on his cardinals, finches, juncos and doves, he asked whether there was something about woodpecker behavior that rendered them vulnerable to hawk predation.
COMMENT
Interesting predation behaviour by one or more hawks on your woodpeckers!
Three in a month’s period with no similar attacks on your other backyard birds is certainly worth pondering!
The only things I can think of are the following.
FIRST, perhaps the posture of woodpeckers, i.e. hanging vertically with their eyes looking forward to their food, might make them more vulnerable to an attack from behind. Perhaps even the noise of their pecking might dull their hearing ability? But that begs an important question - why adopt a feeding or resting posture that might be fatal in the first place?
SECOND, the fact that you have had not one but three woodpeckers lost to possibly the same hawk, likely a Sharp-shinned or Cooper’s hawk, might mean that the raptor has developed a particular search image for these birds and perhaps even a successful foraging strategy. The hawk would have to find a way to counteract a woodpecker’s typical response to any predator aside from flying away and that is a quick movement to the other side of the tree they are clinging to. Perhaps that is not possible or useful on your feeder? As for why woodpeckers rather than cardinals, finches, and even doves, a Coop’s favourite prey, I doubt that they taste any different to a hawk!
Sorry, that is the best I can come up with. Thankfully, hairy, downy and many other woodpecker species are not showing any signs of declining numbers in North America.
While I probably should not admit to it, my wife and I do make use of those amazingly low prices at our local Costco store. Yes, I am aware that some folks get sucked in and engage in rampant purchasing of things they don’t need, but we are, at least, smart about it. Besides the great deals, there is one other thing that I can always count on seeing at Costco, at least in western North America where I now reside --- lots of Brewer’s blackbirds strutting about the parking lot. I had initially surmised that they were there to climb up into the front of vehicles and glean dead insects off the radiators like some other songbirds have been observed to do (see below), but after some casual observations, I realized that they are scrounging for dropped food bits from customers munching on the various inexpensive snacks sold over the counter at Costco. And if some kind soul throws them a crumb or two, they won’t refuse it. Upon perusing the scientific literature on this species, it turns out that Brewer’s blackbirds are regulars in a large number of shopping mall parking lots all through its range, with Costco being among their favorite haunts.
My guess is that Brewer’s blackbirds do not suffer from ‘object neophobia’ or a fear of novel objects. No, I had not heard of the term either, that is until it showed up in an interesting paper in the June 2016 issue of the journal, Animal Behaviour. Alison Greggor in the Department of Psychology at the University of Cambridge in the U.K. and her colleagues examined this behavior in several corvid species and a number of non-corvids visiting platform feeders (the British call them ‘bird tables’).
You see, as we humans continue to drastically alter habitats on the earth, how fast birds can respond to novel stimuli may alter their chances of survival. The extent to which they do this can be good or bad for them, depending on what the item is. If it is dangerous, e.g. harbors a toxin or predator, then having a high level of object neophobia is useful. But if they are missing out exploiting something of value to them, e.g. a food item, they are hindering their success.
Past studies have shown that less neophobic birds more quickly interact with and solve novel foraging tasks, and in some avian species that inhabit a wide variety of habitats, specifically common mynas and house sparrows, those dwelling in urban environments are less neophobic and generally faster at solving tasks than their rural cousins. The best example I can think are those house sparrows in Australia that learned to trigger photoelectric doors of an airport lounge to gain access and feed upon crumbs on restaurant tables. At the same time, one has to consider the other side of the coin. Living in a human-altered habitat can present a number of life-threatening situations, e.g. exposure to novel predators or poisons, where having a high level of object neophobia can prolong one’s life. In that same species of sparrow, it has been documented that urban birds demonstrate higher levels of object avoidance than their rural counterparts. This has also been reported for shiny cowbirds.
So Greggor and her team presented free-flying bird communities with three kinds of objects:
1) natural items that mirrored natural stimuli (rocks, leaves or sticks found in that area)
2) litter items that represented food items in urban areas (man-made food wrappers such as potato chip bags, jam jars, styrofoam food packages, etc.)
3) novel objects built out of colorful, shiny artificial materials that did not resemble any naturally occurring shape or animal and contained no parts resembling eyes. They did this by establishing twelve bird tables in distinct geographical regions across the east and southwest of England with varying human population sizes that were representative of an urban and a rural habitat.
The study focused on five European corvid species: jackdaws, jays, rooks, magpies and crows, and seven non-corvid species: blue tits, great tits, European robins, common blackbird, common wood-pigeon, common chaffinch and house sparrow. Greggor and her colleagues were particularly interested in the corvid species if only because this group of birds has been shown to be paradoxically highly neophobic of foreign objects but also highly innovative in exploiting novel food sources.
To aid the study, a goodly number of these birds had been previously captured and leg-banded for identification. Moreover, before presenting the various objects, peanuts were offered to the birds to get them accustomed to visiting the feeding stations.
Greggor and associates predicted that:
1) the corvids would demonstrate a higher level of neophobia than non-corvids towards novel objects within habitats
2) both sets of species would reduce their neophobic behavior in urban areas towards objects that would be less novel there, e.g. litter
3) foraging birds would be more likely to approach objects after a member of their own species visited first.
Of the 77 experimental trials run, the team recorded a total of 4,300 visits to their bird tables whereupon 15,245 pieces of food were consumed. All five corvid species and all seven non-corvid species participated. Since the corvid visits were generally very brief, their presence did not deter the other species from attending the bird tables.
So what did they find? First, corvids were significantly more neophobic than the other species in avoiding tables bearing any one of the three kinds of objects, but were selective in how they responded to object types after a member of their own kind table foraged at the table first. In short, while corvids were willing to visit a table after one of their kind ‘broke the ice’, so to speak, they definitely ate and visited less at tables containing novel items. Second, there was no reduced neophobia in urban birds, as responses toward novel objects were similar in both habitats. However, both corvids and non-corvid groups arrived faster at tables bearing litter items in urban than rural areas. This likely reflects a specific reduction in fear toward a commonly occurring type of object.
Greggar and her team concluded that the corvids’ sensitivity to novelty was so obvious that the presence of new objects on familiar feeding tables, even natural materials that they may have encountered every day, reduced their probability of visiting tables. This should not be surprising, considering the fact that corvids are classified as vermin under U.K. law and are commonly and regularly targeted by various deterrents and culling efforts even in urban areas. On the other hand, the smaller songbirds or non-corvids represent birds that humans actively encourage to feed in their yards. In the U.K., no less than 60 percent of households with gardens provide food for wild birds.
How does all this fit with the corvids’ well known high rates of behavioral innovation? Well, we do not yet know how their neophobia subsides to allow them to manipulate and solve problems, but these highly intelligent birds seem to be able to rapidly learn to categorize novelty as ‘safe’ or ‘unsafe’. A number of studies have previously shown that corvids are able to recognize the faces of ‘dangerous’ humans or known versus unknown predators. The fact that the corvids in Greggor’s study had no problem visiting feeders containing natural and litter items but were less likely to do so at feeders bearing novel objects suggests that they were able to use social cues to classify objects as novel or safer according to their degree of novelty. This would explain why corvids can be so neophobic but at the same time, highly innovative around objects with which they have had prior experience.
With a human population of 7 billion and counting, and more and more wild habitat being turned into suburban and urban habitat, it becomes imperative that more studies on neophobia in birds must be done to better understand its importance in conservation and wildlife management contexts.
On a somewhat related note to all of the aforementioned, I was intrigued by an observation reported in the June 2016 issue of the Wilson Journal of Ornithology. It refers to the use of automobiles as shelter by the ubiquitous house sparrow. In the winter of 2015, Laure Cauchard and Thomas Borderie of the Department of Biological Sciences at the University of Montreal recorded on two different days a group of house sparrows sheltering under the fenders of several cars, i.e. in those empty spaces between the wheels and the fenders. Interestingly, the cars were located 10 to 15 feet from the bushes where the birds usually sheltered. On February 2, the day was bitterly cold (1 degree F) and snow (about 4 inches), while on April 13, the day was warmer (50 degrees F) but rainy. In each case, about 4 to 5 birds were involved and it was their endless chatter that attracted the attention of Cauchard and Borderie.
After ruling out the possibilities that the sparrows were inside the fenders looking for insects in other parts of the vehicles, as has been reported previously in this species, or gathering grit from the tires or inside fenders to aid in digestion, the authors are confident in proposing that the birds were simply using the unusual shelter as a means to avoid inclement weather, i.e. cold, snow and rain. And if the vehicles in question had been recently used, the warmth from the engine might have added even more to the birds’ comfort. Their constant flitting back and forth between the cars and the nearby bushes is suggested by the authors to be sentinel behavior whereupon the birds are simply keeping a vigilant eye out for cats, humans, and the like.
As much as many North American bird-lovers might despise the invasive house sparrow for out-competing native species for nest cavities, its street smarts are something to be respected. A total of 41 examples of innovative behavior have been reported for the house sparrow, but this is the first time one has involved a non-feeding activity, in this case sheltering under an automobile. Furthermore, while this behavior might well have been observed by others previously, Cauchard and Borderie were not able to find any published information on any bird species using a vehicle as shelter from bad weather. With that in mind, they encourage bird-watchers to publish anecdotes of behavior that they believe to be highly unusual or never seen before. It’s the kind of material that ends up in this column.
Certain Birds Suffer FROM 'OBJECT NEOPHOBIA'
