Featured Research

from universities, journals, and other organizations

Birds Have A Good Sense Of Smell

Date:
July 16, 2008
Source:
Max-Planck-Gesellschaft
Summary:
Sight and hearing are the most important senses for birds -- this is at least the received wisdom. By studying bird DNA, however, researchers have now provided genetic evidence that many bird species have a well-developed sense of smell.

The nocturnal Kakapo, one of the nine bird species in the study, probably recognises fruit according to their aroma. The same applies to the brown kiwi of New Zealand.
Credit: Don Merton

Sight and hearing are the most important senses for birds - this is at least the received wisdom. By studying bird DNA, however, researchers at the Max Planck Institute for Ornithology, along with a colleague at the Cawthron Institute in New Zealand, have now provided genetic evidence that many bird species have a well-developed sense of smell (Proceedings of the Royal Society B, 16.07.2008).

The sense of smell might indeed be as important to birds as it is to fish or even mammals. This is the main conclusion of a study by Silke Steiger (Max Planck Institute for Ornithology) and her colleagues. The sense of smell in birds was, until quite recently, thought to be poorly developed.

Recent behavioural studies have shown that some bird species use their sense of smell to navigate, forage or even to distinguish individuals. Silke Steiger and her colleagues chose a genetic approach for their study. Their research focused on the olfactory receptor (OR) genes, which are expressed in sensory neurons within the olfactory epithelium, and constitute the molecular basis of the sense of smell. The total number of OR genes in a genome may reflect how many different scents an animal can detect or distinguish. In birds such genetic studies were previously restricted to the chicken, hitherto the only bird for which the full genomic sequence is known.

In addition to the chicken, the researchers compared the OR genes of eight distantly related bird species. They estimated the total number of OR genes in each species’ genome using a statistical technique adapted from ecological studies where it is used to estimate species diversity. They found considerable differences in OR gene number between the nine bird species. The brown kiwi from New Zealand, for example, has about six times more OR genes than the blue tit or canary.

"When we looked up the relative sizes of the olfactory bulb in the brain, we also noticed similar big differences between species", said Steiger. "It is likely that the number of OR genes correlates with the number of different smells that can be perceived. As the olfactory bulb is responsible for processing olfactory information, we were not too surprised to see that the number of genes is linked to the size of the olfactory bulb." Wide variation in numbers of OR genes, and sizes of olfactory bulbs, has also been found amongst mammals.

The implication of this finding is that different ecological niches may have shaped the OR gene repertoire sizes in birds, as has been suggested for mammals. The high number of OR genes in the kiwi could be explained by this bird’s unusual ecological niche. Unique among birds, the nostrils of the night-active kiwi are at the tip of the bill. When kiwis probe the forest floor in search of food, they are guided by smell rather than sight. Indeed the snuffling, nocturnal kiwis are sometimes considered to be New Zealand’s equivalent of a hedgehog!

Besides the total number of OR genes, the researchers estimated which proportion of these genes are functional. This was done because, in mammals, a reduced dependence on the sense of smell is associated with OR genes gradually accumulating mutations and so becoming non-functional. For example, in humans, which have a poor sense of smell compared with most other mammals, only about 40% of all OR genes may be functional. However, in the bird species studied by Steiger et al., the large majority of the OR genes were functional, again indicating that the sense of smell is much more important in birds than previously thought.

From the analysis of the chicken genome three years ago a new class of OR genes was found. Now Silke Steiger and her colleagues have shown that this class of genes seems to be a shared feature of all birds, while such OR genes are not found in other vertebrates such as fish, mammals or reptiles. The specific function of this class of bird-specific OR genes remains unknown.


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Journal Reference:

  1. Steiger et al. Avian olfactory receptor gene repertoires: evidence for a well-developed sense of smell in birds? Proceedings of The Royal Society B Biological Sciences, 2008; 1 (-1): -1 DOI: 10.1098/rspb.2008.0607

Cite This Page:

Max-Planck-Gesellschaft. "Birds Have A Good Sense Of Smell." ScienceDaily. ScienceDaily, 16 July 2008. <www.sciencedaily.com/releases/2008/07/080716111421.htm>.
Max-Planck-Gesellschaft. (2008, July 16). Birds Have A Good Sense Of Smell. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2008/07/080716111421.htm
Max-Planck-Gesellschaft. "Birds Have A Good Sense Of Smell." ScienceDaily. www.sciencedaily.com/releases/2008/07/080716111421.htm (accessed October 22, 2014).

Share This



More Plants & Animals News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Reuters - US Online Video (Oct. 21, 2014) Police in Gary, Indiana are using cadaver dogs to search for more victims after a suspected serial killer confessed to killing at least seven women. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
White Lion Cubs Unveiled to the Public

White Lion Cubs Unveiled to the Public

Reuters - Light News Video Online (Oct. 21, 2014) Visitors to Belgrade zoo meet a pair of three-week-old lion cubs for the first time. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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