Featured Research

from universities, journals, and other organizations

Coastal Birds "Feel" Their Prey Under The Sand

Date:
February 11, 1999
Source:
Netherlands Organization For Scientific Research
Summary:
Knots (a kind of sandpiper) can locate their favourite food -shellfish- under wet sand by inserting their beak half a centimetre into the sand for a few seconds. Scientists at the NWO's Netherlands Institute for Sea Research (NIOZ) and the universities of Groningen and Leiden have carried out experiments to demonstrate this. The birds' ability to do so seems to be based on a hydro-dynamic principle.

Knots (a kind of sandpiper) can locate their favourite food -shellfish- under wet sand by inserting their beak half a centimetre into the sand for a few seconds. Scientists at the NWO's Netherlands Institute for Sea Research (NIOZ) and the universities of Groningen and Leiden have carried out experiments to demonstrate this. The birds' ability to do so seems to be based on a hydro-dynamic principle.

The locational ability of the knots was demonstrated in experiments in which the researchers hid little stones in the sand. That the birds can detect stones is remarkable because stones –obviously enough– do not send out any signals. They do not move, their temperature does not differ from that of the sand, and they have no smell or electro-magnetic field; they can therefore not be observed with the birds' normal sense organs. The birds' ability to detect them nevertheless must therefore be based on their beaks' being sensitive to differences in currents in the water in wet sand between the individual grains, stones, or shells. Tame knots used in the experiments were unable to find hidden stones in dry sand.

Under the horny layer of the end of their beak, knots have clusters of 10 to 20 corpuscles of Herbst in the bone and these are sensitive to differences in pressure. When the bird sticks its sensitive beak into the sand at low tide, it produces a pressure wave because of the inertia of the water in the interstices between the particles. The pattern thus created betrays the presence of objects which are larger than the grains of sand. Knots are able to read the disturbances in the pressure field and perhaps even amplify it to some extent. The rapid up-and-down movements of the bird's beak loosen the grains of sand, which then become packed together more tightly, displace the interstitial water and cause the residual pressure around the object concerned to increase.

The birds' ability to detect food also explains why knots can find enough to eat on intertidal flats where there are only few shellfish. It also explains for the first time why these wading birds only forage on wet sand; in dry sand, the sensor in their beak does not work. As soon as the tide has gone out far enough for the shallows to dry out, the birds therefore fly to areas which are still wet. The nature of their localising ability means that knots are unable to distinguish between stones and shellfish in the sand. It is therefore no wonder that they never look for food in areas where the sand contains stones, no matter how much shellfish could be found there.


Story Source:

The above story is based on materials provided by Netherlands Organization For Scientific Research. Note: Materials may be edited for content and length.


Cite This Page:

Netherlands Organization For Scientific Research. "Coastal Birds "Feel" Their Prey Under The Sand." ScienceDaily. ScienceDaily, 11 February 1999. <www.sciencedaily.com/releases/1999/02/990211072751.htm>.
Netherlands Organization For Scientific Research. (1999, February 11). Coastal Birds "Feel" Their Prey Under The Sand. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/1999/02/990211072751.htm
Netherlands Organization For Scientific Research. "Coastal Birds "Feel" Their Prey Under The Sand." ScienceDaily. www.sciencedaily.com/releases/1999/02/990211072751.htm (accessed August 27, 2014).

Share This




More Plants & Animals News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Super Healthful Fruits and Vegetables: Which Are Best?

Super Healthful Fruits and Vegetables: Which Are Best?

Ivanhoe (Aug. 27, 2014) We all know that it is important to eat our fruits and vegetables but do you know which ones are the best for you? Video provided by Ivanhoe
Powered by NewsLook.com
Panda Might Have Faked Pregnancy To Get Special Treatment

Panda Might Have Faked Pregnancy To Get Special Treatment

Newsy (Aug. 27, 2014) A panda in China showed pregnancy symptoms that disappeared after two months of observation. One theory: Her pseudopregnancy was a ploy for perks. Video provided by Newsy
Powered by NewsLook.com
Raw: Firefighters Rescue Puppy Stuck in Tire

Raw: Firefighters Rescue Puppy Stuck in Tire

AP (Aug. 26, 2014) It took Houston firefighters more than an hour to free a puppy who got its head stuck in a tire. (Aug. 26) Video provided by AP
Powered by NewsLook.com
Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Newsy (Aug. 26, 2014) A study published in the journal "Neurology" interviewed more than 19,000 people and found 15 percent suffer from being "sleep drunk." Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins