Sunday, July 21, 2013

Sea birds use sense of smell to navigate

Scientists have long known that reversals in the Earth’s magnetic field can affect climate, habitats and navigation of humans and wildlife. In the past 10 million years, there have been 4 or 5 reversals or "excursions" per million years.

Migration and motion of creatures like bats, the dung beetle, and sea birds is not affected because they use other sensory means of navigation. Some bats use vision and others navigate using a system of sonar called "echolocation." The African "rolling" dung beetle navigates by visual clues taken from observing the Milky Way.

A recent study of sea birds reveals that they rely on olfactory clues. Here is a summary of that report:

Pelagic birds, which wander in the open sea most of the year and often nest on small remote oceanic islands, are able to pinpoint their breeding colony even within an apparently featureless environment, such as the open ocean. The mechanisms underlying their surprising navigational performance are still unknown. In order to investigate the nature of the cues exploited for oceanic navigation, Cory's shearwaters, Calonectris borealis, nesting in the Azores were displaced and released in open ocean at about 800 km from their colony, after being subjected to sensory manipulation. While magnetically disturbed shearwaters showed unaltered navigational performance and behaved similarly to unmanipulated control birds, the shearwaters deprived of their sense of smell were dramatically impaired in orientation and homing. Our data show that seabirds use olfactory cues not only to find their food but also to navigate over vast distances in the ocean. 

Read the full report here.

Between geomagnetic reversals, volcanism, earthquakes, tsunamis, climate changes, and the expansion and contraction of the seas, Earth is constantly changing. Life on Earth is constantly adapting. How wonderful is God's design!

The British Geologic Survey reports, "There is no obvious correlation between human development and reversals. Similarly, reversal patterns do not match patterns in species extinction during geological history.

Some animals, such as pigeons and whales, may use the Earth's magnetic field for direction finding. Assuming that a reversal takes a number of thousand years, that is, over many generations of each species, each animal may well adapt to the changing magnetic environment, or develop different methods of navigation."

Related reading:  The Dung Beetle and Heavenly Lights; Climate Cycles Indicate a Dynamic Earth; The Bi-Polar Seesaw

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