Ducking the Issue


Three days ago on April 20th, the post reported on the tactics used by sheep in maintaining optimum vigilance so as to avoid being eaten while eating. Ducks have similar problems when it comes to ending up as dinner. Zimmer et al of the U of Strasburg have just published their study on duck tactics (1). Tufted ducks, teals and mallards were all recruited to the program. It must be stressed that none ended up as that well-known French dish, Canard a l’Orange, (a recipe is given in reference 2).

The whole time budget for the ducks was recorded. That is the times that they allocated to watching, eating, preening and sleeping. This was for control groups, and groups that had a quiet period followed by a period of predation activity, followed by a period free of disturbance. As mentioned above none were actually eaten and predation was simulated by a fast moving model monster truck rushing at them like a fast moving terrestrial predator determined to dine on duck today. ( The truck was an E-Zilla FWD Hot-bodies™ for the nerdy who wish to check the results at their local duck pond.)

The groups of disturbed ducks, that is those who thought that the radio controlled truck had come to eat them, spent less time eating or preening. The fascinating result is that they did not spend more time keeping watch. So what did they do to balance the budget? They slept.

Sleeping may not seem to be the best strategy to avoid being eaten. However, ducks are light sleepers, and although they may not sleep with one eye open, they do frequently open one eye to take a peek and then it's back to sleep. This peek, sleep, peek cycle make it difficult to creep up on them. Perhaps this is why we invented shotguns?


  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0018977
  2. http://www.foodnetwork.com/recipes/emeril-lagasse/classic-duck-a-lorange-recipe/index.html

Busy Morning

It was a beautiful morning by the Ponds  today. The water level has peaked but it's still high. There was very little wind and the sun felt warm. Warm enough to get the turtles out sunning themselves on the logs, all jumbled up on top of each other.

 The big news though is that the ospreys are back in residence. Lots of new twigs and most of the grass kicked out of the nest. They are still in the middle of the makeover. However, they seemed a little shy about having their pictures taken by the paparazzi and went off for an early lunch over by the river.
 























Hatching has been going on apace and we’ll soon be tripping over goslings as the grass next to the sidewalk is particularly luscious but not too long for little beaks to cope with.


The youngsters are kept under control by uncles and aunts as well as mom and pop whether they are running about near the road or sailing majestically along as a flotilla.


So far there has been no sign of ducklings, ugly or otherwise, and they may have been scheduled for next months entertainment. As usual when the Ponds are full, the cormorants have decamped to other sites. I noticed that the pond behind the Fern Ridge Dam had a log with a dozen of them enjoying an after-lunch doze. I’m not sure what that locality has to offer compared to our ponds unless the rent is cheaper outside the city.


Moldy Choice


Orchids are freewheeling members of plant society. Some hang about in trees, accepting any handout that comes their way. Others are more down to earth, and put down roots. Even these are not trustworthy.

When plants require insects for pollination work, they offer a reward in the form of nectar for a job well done. Orchids are more slippery than that, as they make promises of food or sex to naïve insects with no intention of honoring the deal.

The latest con trick to be studied is with the slipper orchid Cypripedium fargesii found in China. The study by Ren et al is published in The Proceedings of the National Academy of Sciences (1). The chosen mark for the con trick in this case is the flat-footed fly which spends its lowly life munching on mold spores found in rotting vegetation.

The business end of the orchid has lots of little black spots that to you, me or a flat-footed fly look like black mold spores, laid out in a trail promising greater delights to those following it to the source deep within the flower. Exuding from the depths of the slipper comes the tantalizing odor of rotting vegetation with the promise of an abundance of tasty spores. The entrance is low so to get to the feast the fly has to brush against the orchid’s anthers and collects a pollen load but there is no lunch to be found. The hungry fly now rushes to the next promise offered by a nearby slipper. The only ones to get any benefits are the Cypripediums who are now sexually replete while the flatfoots are stomping around in a ravenous state.


http://www.pnas.org/content/early/2011/04/12/1103384108

Flock Wisdom


As a sheep munches on the grass, it has to make important decisions. However, we may not think of sheep as being widely known for their decision-making ability. But to a sheep, the decision to get its head down to munch grass or get its head up to look for wolves, or any hungry predator including the rustler with his truck and plans to sell lamb chops and legs of mutton, is just that. More heads up time means less food, simple but, as always, the risk assessment gets difficult at the boundary between hunger and security.

A part solution to the problem is to flock together and cooperate on sentry duty, and this has been universally adopted from time immemorial. At first sight, the bigger the group the better. With everyone doing their bit, the defense cost to an individual flocker is lower if the flock is larger. This is known as the ‘group size effect’ and as size matters, the flockers will make bigger flocks.

The problem is complacency. Doing your bit for defense in a flock or herd is voluntary, and if there are huge numbers, an individual has less incentive to volunteer. “Not my turn” can be baa’ed too often and a sneak attack from wolves intent on civilizing the flock can occur. Last Friday, a study of the problem was published (1). The authors were Michelena and Deneubourg from U libre de Bruxelles.

Firstly, their study showed that sheep do what sheep do. The tendency to vote with your neighbor resulted in more heads up awareness. Secondly, they highlight the challenge each individual has in balancing public and private information. It is this balance that governs the tempo, that is, whether lots of short heads down are favored over one long head down. The speed of information spread through the social network is key so setting a tempo which will minimize the response time to an attack while keeping the defense cost at a tolerable level. More sentry duty, less green stuff.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0018631

Fun Fishy Fact


The orangutans move around the Borneo forest by swinging among the trees and spending little time on the forest floor. Fruit is the larger part of their diet. They regularly eat figs, and keep regular. They have pretty strong stomachs and will eat the fruit of the climbing plant Strychnos ignatti, which is a source of strychnine. Most of us would keel over after breakfasting on those fruits but not the Orangs, they just drool a lot for a while. They also like honey and birds eggs, and will also indulge in insect eating.

Those Orangs living in Borneo appear to have been paying a lot of attention to current concerns over wellness and fitness programs. The physical exercise and lots of fruit have been a standard part of their lifestyle for a very long time. Minerals they get by occasionally coming down to earth and eating it.

But what about their omega-3 and omega-6 fatty acids? Their only choice is fish, and that’s a problem because they can’t swim. Scavenging dead fish washed up at the edges of large ponds is not Cordon Bleu stuff – fresh is required for that. Russon has reported on their fishing tactics (1). They lean over a pond and stab at the catfish until they give themselves up and flop onto the shore in a panic.

Russon went to the trouble of directing a movie of this by stocking a pond with excitable young catfish extras and filming the stars jabbing away with great élan. Their little grey cells were much enhanced after their dinner. Now all they’ll need is to drink a glass of red wine a day, and maybe try and cut back on the strychnine.


  1. http://news.discovery.com/animals/orangutans-fishing-primates-fish-110418.html

Defensive Moves


Ants come in variety of shapes and sizes and live in large communities in which the various members cooperate to make the colony thrive. Colonies have different specialties, such as cutting leaves for fungal farms or the free range farming of aphids for honeydew. Ant colonies appreciate how well off they are, and will defend their patch vigorously if they can. Some species have nastier habits than others. For example, Protomagnathus americanus makes slave raids on adjacent colonies of other species to carry off brood. They don’t succeed without a fight of course, and the host colony can lose many workers and their queen while trying to defend their young.

Being raided and finding your young carried off is not something that a colony is willing to put up with, and a new study (1), by Pamminger et al from U of Munich, has shown how host colonies of Temnothorax curvipinosus mobilized their militias to seek and destroy any slavemaker spies who had infiltrated to assess the cost/benefit of a raid on their colony. The experiments were carried out under laboratory conditions to eliminate extraneous factors such as the seasons and competing colony crowding.

 A dead spy or two left lying about for a few minutes was enough to set off the chemical alarms and the militias cracked down. Non-nestmates who were not from the slavemakers were not treated so harshly, maybe roughed up a bit on occasion, though. No slavemaker scout was shown any mercy.

Mobilization took up to 5 minutes, and would last at peak for about 3 or 4 days, with a wind down over the next two weeks. The wind down occurred even though it was still raiding season, indicating that the their defense budget considerations came into play. Mobilization of militias is associated with costs. Such as lowering community foraging efficiency and the increased stress levels reducing longevity and brood production. And a well-run ant community has to work out a balanced budget based on resources and risk.


  1. http://beheco.oxfordjournals.org/content/22/2/255.full

Drongos and Cuckoos


The Kalahari Desert appears to be an inhospitable place, but it’s prime real estate if you’re a meerkat. Hot in the day and cold at night is the typical desert weather. The mornings tend to be slow as everything warms up and the meerkats stand up to let the sun warm their chests, in that typical pose seen so often on posters. They dig around for insects but also munch on lizards and scorpions for lunch. With your head in the ground you’re a prime target for predators like hawks, so the troop has sentries standing guard who call a warning if one is seen and then they all dash for cover.

The fork-tailed drongo bird doesn’t have to time or inclination to go digging around, so it just mimics the meerkat alarm and pops down to steal their lunch. Flower from U of Cambridge has published the final version of his study of this sharp practice (1). The dreaded drongos are sharp enough to toss in a few genuine hawk alarms to maintain their credibility. If the meerkats aren’t working hard enough for the drongos, they are not beyond scaring the pied babblers and stealing their lunch instead.

Mimicry of a different order is the annual practice of cuckoos. Spottiswoode and Stevens from U of Cambridge (2) have recorded a defense being developed by some warblers against the cuckoo finch. Very discriminating species may spot slight differences in the cuckoo’s egg compared to their own. Not all warblers are that capable as the cuckoos are pretty capable mimics.

The latest defense strategy has been to lay lots of different colored and patterned eggs so the cuckoo’s egg is way out of fashion and stands out like last years design at a fashion show. The “oh so yesterday’s” egg is then pierced and kicked out. A high price for being unfashionable.



  1. T.Flower, Proc. R. Soc. B May 22, 2011 278:1548-1555
  2. http://rspb.royalsocietypublishing.org/content/early/2011/04/05/rspb.2011.0401.full?sid=1ea23cb9-f497-4607-8183-4f7911b4b548