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BurnOutBrighter6 t1_irpz4ht wrote

Birds have the ability to sense the Earth's magnetic field, giving them a sense called "magnetoreception" that acts like an internal compass. The actual physical mechanism allowing this magnetic perception to function is currently poorly understood, unless this textbook chapter from 2015 is out of date (in which case someone with more relevant knowledge in the field please update us!).

Chapter 8 - Magnetoreception in Birds and Its Use for Long-Distance Migration

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limacharley t1_irq04yh wrote

Some animals sense magnetic fields. Others follow the stars. Of course, it is pretty easy to tell what direction you are headed just by noting where the sun is. In the morning your shadow points west. In the evening your shadow points east. At noon your shadow points north (in the northern hemisphere)

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smashkraft t1_irq5vw4 wrote

Replying to BurnOutBrighter6 (#68,067)

I’m pretty certain that a while ago I found an article in another sub with additional discoveries. I cannot find the Reddit thread, but this article captures some development that I remembered seeing - it is proteins in their eyes, instead of some feature in their brains, that allows for the magnetoreception.

https://www.sciencealert.com/birds-see-magnetic-fields-cryptochrome-cry4-photoreceptor-2018/amp

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PuzzleMeDo t1_irq93xo wrote

Replying to limacharley (#68,105)

Note that without the magnetoreception, this leads to fairly haphazard navigation. Can't follow the stars on a cloudy night. Still, if you're just trying to head somewhere warm rather than a specific area, it's good enough.

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Saoirsenobas t1_irqrh59 wrote

Replying to araujoms (#68,779)

In the fall the Indigo Bunting becomes restless and wants to constantly move towards their southern migration. Studies were conducted in an observatory with a simulated night sky. With a normal sky the birds almost always trended in the correct direction (south) even if their magnetic sense was interupted. scientists then had the observatory simulate the night sky rotated 180 degrees and noted that the birds now wanted to go north.

Edit: apparently I am bad at making links can anyone help?

Migratory Orientation in the Indigo Bunting, Passerina cyanea. Part II: Mechanism of Celestial Orientation

Stephen T. Emlen

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limacharley t1_irr43v8 wrote

Replying to araujoms (#68,779)

It has been well documented that migratory birds will get confused and circle certain sources of light pollution at night. Some will circle the same building/light source until they die of exhaustion

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iayork t1_irr5x2k wrote

Replying to Saoirsenobas (#68,980)

Square brackets around the text (e.g. title) followed by regular brackets around the link.

[Migratory Orientation in the Indigo Bunting, Passerina cyanea. Part II: Mechanism of Celestial Orientation](https://academic.oup.com/auk/article/84/4/463/5198008)

> I propose that Indigo Buntings are able to determine their migratory direction in a similar manner, by responding to the Gestalt stimuli provided by the patterning of stars

—Migratory Orientation in the Indigo Bunting, Passerina cyanea. Part II: Mechanism of Celestial Orientation

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