Homing pigeons use local natural odors to find their way

Reproducibility study disproves a popular hypothesis about how pigeons successfully return home

Date:  July 26, 2018

Source:  Springer

Homing pigeons use familiar smells to navigate their way across hundreds of kilometers of unfamiliar territory. Researchers have now confirmed that artificial odors cannot be used to stimulate or trigger a pigeon's navigation system. This means that the so-called olfactory activation hypothesis -- which has been proposed by some researchers -- should be disregarded, argues Anna Gagliardo of the University of Pisa in Italy. Gagliardo and her colleagues have published their research in Springer's Journal of Comparative Physiology A.

The researchers set out to test the olfactory activation hypothesis proposed by a team of Portuguese and American scientists in 2009 and 2010, by using similar steps and methods. In order to replicate the study, Gagliardo and her colleagues used 63 adult inexperienced pigeons that were allowed to perform spontaneous flights in their home area. The birds were divided into three experimental groups then each fitted with a GPS-tracking device, and released singly 53 kilometers from home.

The first group was transported in open crates and released without manipulation. Pigeons in group two were carried and kept at the release site in airtight containers ventilated with natural air before they were released. The third group also travelled in an airtight container, with the air filtered to remove most of the natural odorants it might contain. During their travels and before their release, the birds in this group were exposed to the scents of lavender, eucalyptus, rose and thyme. Prior to their release, the nasal cavities of the birds in the second and third groups were washed with a zinc sulphate solution in order to make them temporarily unable to smell.

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Bird senses can improve drone navigation

February 8, 2018 by Signe Brinkløv, ScienceNordic

South American oilbirds combine echolocation and extremely sensitive vision to find their way through dark caves. Decoding how they do this could help develop autonomous drones.

The Danish Drone Strategy aims to put Denmark at the forefront of state-of-the-art drone technology. Both the number of commercial users and authorised drone operators are rising. But for security reasons, the law requires drones to operate within the drone pilot's range of sight.

This limits the use of drones to good visibility conditions and limits their full potential. For example, routine monitoring tasks could be hindered by foggy or cloudy weather. And emergency situations, such as a forest fire or a burning building, could benefit from a drone controlled not by a pilot on the ground, but autonomously via automatic recognition of obstacles.

The question is, how can we further develop and optimise drone technology to avoid such concerns?

Oilbirds, form South America, also known as the guácharo, might hold the answer. But before we get to that, let's consider some examples of how we imitate nature.

Active sensory perception and biomimetic inspiration

By mimicking the shape and function of nature, biologists and engineers have created so-called biomimetic robots that are experts in parkour, able to hear like a lizard, and smell like a sniffer dog.

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Pigeon 'chain of command' aids navigation

Date:  June 9, 2015

Source:  University of Oxford

Summary:  Having a hierarchical social structure with just a few well-connected leaders enables pigeon flocks to navigate more accurately on the wing, new research shows.

Hierarchical organisation also enables flocks to cope better with navigation errors made by individual birds.

Researchers from Oxford University and the Zoological Society of London created 'virtual flocks' of homing pigeons to test how different social networks affect the navigation performance of these groups. The team's simulations looked at everything from no networks (all connections between individuals were of equal strength) to random networks (some connections were stronger than others but randomly distributed) to hierarchical networks with just a few well-connected individuals leading the way.

Flocks in which each individual follows just a single other bird, allowing information to rapidly pass down this 'chain of command', perform best at navigating accurately to a desired location, the study suggests.

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Protein helps birds to navigate via magnetic field

Protein helps birds to navigate via magnetic field

IANS. London | Update: 10:31, Mar 01, 2015

Researchers have found that a magnetically sensitive protein called Cryptochrome that mediates circadian rhythms in plants and animals helps birds to sense the earth’s magnetic field and use it to navigate over long distances. Blue or green light triggers electrons in the protein to produce pairs of radicals whose electron spins respond to magnetic fields.

“As we vary the strength of the magnetic field, we can alter the progress of these photochemical reactions inside the protein,” said Peter Hore, Physicist and lead researcher at University of Oxford.

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Explainer: How Do Homing Pigeons Navigate?

By Tim Guilford, University of Oxford | April 26, 2014 02:10am ET

This article was originally published at The Conversation.The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Pigeons have extraordinary navigational abilities. Take a pigeon from its loft and let it go somewhere it has never been before and it will, after circling in the sky for while, head home. This remarkable capacity extends to places tens even hundreds of kilometres from its home and is all the more remarkable to humans because we are apparently incapable of it ourselves.

But we have long made use of the pigeon’s homing ability, principally for carrying messages in the past. And for several decades now the pigeon has played centre stage in scientists’ attempts to understand the map and compass mechanisms fundamental to bird navigation.

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How Pigeons May Smell Their Way Home

Nov. 5, 2013 — Homing pigeons, like other birds, are extraordinary navigators, but how they manage to find their way back to their lofts is still debated. To navigate, birds require a 'map' (to tell them home is south, for example) and a 'compass' (to tell them where south is), with the sun and the earth's magnetic field being the preferred compass systems. A new paper provides evidence that the information pigeons use as a map is in fact available in the atmosphere: odors and winds allow them to find their way home.

The results are now published in Biogeosciences, an open access journal of the European Geosciences Union (EGU).

Experiments over the past 40 years have shown that homing pigeons get disoriented when their sense of smell is impaired or when they don't have access to natural winds at their home site. But many researchers were not convinced that wind-borne odors could provide the map pigeons need to navigate. Now, Hans Wallraff of the Max Planck Institute for Ornithology in Seewiesen, Germany, has shown that the atmosphere does contain the necessary information to help pigeons find their way home.

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