Friday, 5 August 2016
Friday, 3 June 2016
Saturday, 2 January 2016
|New Caledonian crow uses a ‘hooked stick tool’ |
to hunt for insect prey.
Dr Jolyon Troscianko, from the University of Exeter, and Dr Christian Rutz, from the University of St Andrews, have captured first video recordings documenting how these medium sized, all black crows fashion these particularly "complex" tools in the wild.
The two scientists developed tiny video 'spy-cameras' which were attached to the crows, to observe their natural foraging behaviour.
They discovered two instances of hooked stick tool making on the footage they recorded, with one crow spending a minute making the tool, before using it to probe for food in tree crevices and even in leaf litter on the ground.
The findings appeared in the Royal Society's journal Biology Letters on Wednesday, December 23.
Dr Troscianko is a Postdoctoral Research Fellow in Exeter's Biosciences Department based at the Penryn Campus in Cornwall, who worked on the project while at the University of Birmingham.
"While fieldworkers had previously obtained brief glimpses of hooked stick tool manufacture, the only video footage to date came from baited feeding sites, where tool raw materials and probing tasks had been provided to crows by scientists. We were keen to get close-up video of birds making these tools under completely natural conditions. New Caledonian crows are notoriously difficult to observe, not just because of the challenging terrain of their tropical habitats, but also because they can be quite sensitive to disturbance. By documenting their fascinating behaviour with this new camera technology, we obtained valuable insights into the importance of tools in their daily search for food." said Dr Troscianko.
To obtain a 'crow's-eye view' of this elusive behaviour, the two researchers developed video cameras that are attached to the crows' tail feathers. The cameras are about the weight of a British 2-pound coin, and a tiny integrated radio beacon let the scientists recover the devices once they had safely detached after a few days. Dr Christian Rutz, Reader in the School of Biology in St Andrews, explains: "These cameras store video footage on a micro-SD card, using technology similar to that found in people's smart phones. This produced video recordings of stunning quality."
The team deployed 19 cameras on crows at their chosen dry forest study site, where in hundreds of hours of fieldwork, despite two brief glimpses with binoculars, they had never managed to film crows manufacturing hooked stick tools.
The scientists were excited to record two instances of this behaviour on footage recovered from ten birds in their latest study.
"The behaviour is easy to miss -- the first time I watched the footage, I didn't see anything particularly interesting. Only when I went through it again frame-by-frame, I discovered this fascinating behaviour. Not once, but twice!" said Dr. Troscianko.
"In one scene, a crow drops its tool, and then recovers it from the ground shortly afterwards, suggesting they value their tools and don't simply discard them after a single use." According to Rutz, this observation agrees with recent aviary experiments conducted by his group: "Crows really hate losing their tools, and will use all sorts of tricks to keep them safe. We even observed them storing tools temporarily in tree holes, the same way a human would put a treasured pen into a pen holder."
|Still images from footage obtained with miniature video cameras attached to wild new caledonian crows.|
- Jolyon Troscianko, Christian Rutz. Activity profiles and hook-tool use of New Caledonian crows recorded by bird-borne video cameras. Biology Letters, 2015; 11 (12): 20150777 DOI: 10.1098/rsbl.2015.0777
Tuesday, 20 October 2015
|Honey bee foraging at a feeder with caffeinated sucrose solution|
Credit: Dr. Roger Schürch
We all love to start our day with a hot cup of coffee. Now, a new study appearcing in the Cell Press journal Current Biology on October 15 finds that honey bees find caffeinated nectar irresistible too.
In fact, it seems that honey bees may select caffeinated nectar over an uncaffeinated but otherwise equal-quality alternative. As a result, the researchers believe plants may be lacing their nectar with caffeine as a way to pass off cheaper goods.
"We describe a novel way in which some plants, through the action of a secondary compound like caffeine that is present in nectar, may be tricking the honey bee by securing loyal and faithful foraging and recruitment behaviors, perhaps without providing the best quality forage." said Margaret Couvillon of the University of Sussex.
"The effect of caffeine is akin to drugging, where the honey bees are tricked into valuing the forage as a higher quality than it really is. The duped pollinators forage and recruit accordingly." added Roger Schürch, of the University of Sussex and the University of Bern.
Couvillon, Schürch, and their colleagues were aware of earlier studies, which found that honey bees are better at learning and remembering particular scents when they are under the influence of caffeine. The findings suggested a role for reward pathways in the bees' brains.
"I could not help but wonder how caffeine would affect the natural behaviors as seen in the field." Couvillon said, noting that the nectar of many flowering plants contains caffeine in low concentrations.
To investigate, the researchers tested bees' responses to a sucrose solution with field-realistic doses of caffeine or without. They found that the caffeine caused honey bees to forage more and to direct their friends to the caffeinated forage more frequently with waggle dances. The caffeine quadrupled the recruitment dances of bees to those feeders in comparison to uncaffeinated controls.
Bees were more persistent about returning to sites where they'd previously found caffeinated nectar, even after the feeder had run dry. After sipping caffeine, bees were also less inclined to search for other resources, a behavior that could be useful when the well runs dry.
"We were surprised at how, across the board, we saw an effect of caffeine just about everywhere we looked in foraging and recruitment, and all in the direction to make the colony more faithful to the caffeinated source compared to an equal-quality, uncaffeinated source." said Schürch.
Based on their observations of the individual bees' behaviors, the researchers' model suggests that caffeinated nectar could reduce honey production in colonies if indeed plants reduce the sweetness of their nectar. The findings come as a reminder that the interests of plants and their pollinators don't always align.
The researchers say it would now be interesting to find out whether plants that lace their nectar with a secondary compound like caffeine also make nectar that's less sweet. And, they note, caffeine isn't the only secondary compound found in nectar.
"It would be interesting to determine the effects of other compounds. It may be that chemistry is a popular way in which plants can get the upper hand on their pollinators." saidCouvillon.
The authors are funded by the Nineveh Charitable Trust, the Natural Environment Research Council, the University of Sussex, Damascus University, and Rowse Honey Ltd. Additional research funding was provided by Waitrose Ltd. and Burt's Bees.
|Pet me dolphin!!|
This is probably one of the cutest and strangest youtube videos you have ever seen! A cat and dolphin playing together at the Theater of the Sea, a marine animal park in Islamorada, Florida in 1997. The names of the dolphins are Shiloh and Thunder and the cat is Arthur. Enjoy: