{"id":5358,"date":"2023-01-04T22:00:00","date_gmt":"2023-01-04T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=5358"},"modified":"2022-12-11T15:06:50","modified_gmt":"2022-12-11T15:06:50","slug":"how-do-geese-know-how-to-fly-south-for-the-winter","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/how-do-geese-know-how-to-fly-south-for-the-winter\/","title":{"rendered":"How do geese know how to fly south for the winter?"},"content":{"rendered":"\n
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\n Geese fly day or night, depending on when conditions are best.\n sharply_done\/E+ via Getty Images<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\nTom Langen<\/a>, Clarkson University<\/a><\/em><\/span>\n\n
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Curious Kids<\/a> is a series for children of all ages. If you have a question you\u2019d like an expert to answer, send it to curiouskidsus@theconversation.com<\/a>.<\/em><\/p>\n\n

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How do geese know how to fly south for the winter? \u2013 Oscar V., age 9, Huntington, New York<\/strong><\/p>\n<\/blockquote>\n\n

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To be ready to migrate in the fall, geese start preparing in midsummer. Babies born in the spring are mostly grown up by then. Adult geese grow a new set of plumage<\/a> after shedding their old feathers \u2013 a process called molting<\/a>.<\/p>\n\n

They need flight and body feathers to be in good condition for the long flight ahead, and to insulate their bodies from the winter cold. For a few weeks during this process, geese can\u2019t fly at all, and they stay out on the water to avoid predators.<\/p>\n\n

Geese have a clock in their brain that measures how much sunlight there is each day<\/a>. The days grow shorter during the late summer and early fall, and that\u2019s how geese know it\u2019s time to get ready for the journey south. Families join together in larger flocks. Geese gorge on grains and grasses to fatten up in preparation for their journey.<\/p>\n\n

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\n Geese fattening up by eating some underwater foods.<\/span>\n Jennifer Yakey-Ault\/iStock via Getty Images<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

When it\u2019s time to go<\/h2>\n\n

There are two different types of bird migration. For most bird species that migrate from temperate climates to the tropics in winter, migration is instinctual<\/a>. These birds, such as swallows, orioles and warblers, leave their northern breeding place before weather turns harsh and food becomes scarce.<\/p>\n\n

Most migrate at night, individually rather than in flocks, and they know where to go and how to get there without guidance from parents or other birds. They migrate continuously, except for short stopovers to fuel up on insects, fruit, or seeds before continuing on their way. <\/p>\n\n

Canada geese and other migratory geese species are different. They usually remain in their summer range until the weather is cold, water starts to freeze, and food gets hard to come by. Once conditions become so tough<\/a> that they can\u2019t find enough to eat, geese migrate.<\/p>\n\n

Maybe you\u2019ve observed flock members signaling they\u2019re ready to go: They honk loudly and point their bills toward the sky<\/a>. Single families of geese, or flocks of several families together, take off and head south. Flocks join with other flocks. Geese fly by day or night, depending on factors like weather conditions or brightness of the moon.<\/p>\n\n

Geese navigate based on experience<\/a>, using landmarks including rivers, coastlines and mountain ranges. They may also use celestial cues such as the sun and stars. Geese have a physical compass in their head that allows them to tell north and south by detecting the Earth\u2019s magnetic field<\/a>.<\/p>\n\n

Young geese learn the migration route and landmarks by following their parents and other experienced geese. People who have raised and socially bonded with geese have even taught the birds new migration routes by leading them in an ultralight aircraft \u2013 as in the movie \u201cFly Away Home<\/a>.\u201d<\/p>\n\n[Expertise in your inbox. Sign up for The Conversation\u2019s newsletter and get expert takes on today\u2019s news, every day.<\/a><\/em>]\n\n

On their way<\/h2>\n\n

Geese are heavy birds, and they fly fast \u2013 over 30 miles per hour \u2013 using powerful wing beats, rather than gliding like eagles or vultures. All this flapping for a heavy bird takes a lot of energy<\/a>. Geese work very hard during migration flights. To reduce the effort, geese fly at night when the air is calmer, or in the day when there\u2019s a helpful tailwind<\/a>; they avoid flying into a headwind that would blow them backward.<\/p>\n\n

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\n The different wing positions of these greylag geese show their flapping motion, with the individual at the tip of the V working the hardest.<\/span>\n Anagramm\/iStock via Getty Images<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

In addition, they have another energy-saving trick. To reduce drag and to receive a little extra lift, geese fly close behind and about one wing length to the side of the one immediately in front. When all flock members do this, the familiar V shape appears.<\/p>\n\n

This form of drafting, also called vortex surfing<\/a>, saves a lot of energy. Following another bird at the right distance blocks any headwind. The flapping of the bird ahead creates a forward movement of air called a slipstream, which helps pull the trailing bird forward. And little pockets of spinning air, called vortices, produce lift that helps keep a trailing bird aloft. The same physics explains why fighter jets fly in V formation to conserve fuel.<\/p>\n\n

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