You might have heard about migration in birds and studied about the routes of some. Did you also ever ponder on the question regarding how animals know when to migrate and where to migrate? When an animal sets out on a thousands-of-kilometres long journey, it must have a motive behind. That motive is, obviously, there. But how do they know when it is the right time to undertake that journey.

There are multiple responses tothe query, “How do animals know when to migrate? Usually, there are changes in the environment that trigger the need in the animals to relocate to some other place. Therese Shea (2015) in “What Is Animal Migration?”, expresses the same opinion that something in the environment makes the animals feel that it is time to leave.

How Do Animals Know When to Migrate?

Listed below are some of the factors which let the animals feel when to migrate.

Low Temperature:

Temperature is an important factor behind a long migration. While the cold-blooded creatures may go for hibernation during winter, the warm-blooded animals migrate to warmer regions to spend winters when it becomes difficult for them to survive in the freezing cold weather.

For example, the bar-tailed godwit flies thousands of kilometres from the Arctic and other colder regions to as far a location as Australia and New Zealand to spend winters in these warmer areas.

Less Food:

When animals cannot get enough food to survive in their habitat, they feel the need to undertake a long migration. On the way, they have to face several troubles such as harsh environmental conditions and encounters with predators which hunt down many members of the group.

For example, many birds and animals in North America migrate south each fall for food despite the fact that a safe homecoming is not guaranteed for them. In winter, when the ground is covered with snow, the insects, fruits, and the vegetation they feed on become scarce, they relocate to the areas where there’s plenty of food.

Water Scarcity:

According to Holden Strauss in “Animal Migration”, when animals migrate, they do so for the sake of a certain kind of land, weather, water, or food source. So, the scarcity of water also plays an important role in this regard.

Breeding:

Sometimes, animals migrate for the sake of finding suitable breeding grounds. Here you can again take the example of the bar-tailed godwits. After spending winters in warmer areas like Australia and New Zealand, they migrate back to the Arctic for breeding. This factor provides an answer to the question, “How do animals know when to migrate?”

Competition Among Species:

The competition among different species of animals for food and space may also force some species to relocate to other areas. When the competition becomes fierce, those on the weaker side resort to migration.

Amount of Sunlight Available:

As you can guess, the factors for migration ‘low temperature’ and ‘amount of sunlight available’ are related to each other. When an animal is travelling to a warmer area, it is looking for more amount of sunlight.

Genetic Factors:

Scientists are not pretty sure how a new generation of the globe skimmer dragonflies knows where to go in its path of migration between India and Africa. They have found that each individual does not follow its parents or remember a route it travelled before.

This makes answering the question “How do animal know when to migrate?” even more difficult. Trying to respond to this query, Therese Shea (2015) opines that dragonflies are born with a sense that tells them which path to follow during migration.

Preparing for the Trip:

Responding to different environmental and genetic factors, a migratory bird’s brain cues its body to prepare for the trip. Before setting off on a journey, many animals like whales and birds eat a lot more than usual because a long migration takes a huge amount of energy.

Fast Facts about Animal Migration:

Here are some mind-boggling facts about animal migration.

• Did you know about the bird that outdoes all human-made aircraft? The bar-tailed godwit is a bird that holds the world record for the longest non-stop flight!
• Scientists use satellite and different forms of radio transmitters to pinpoint a bird’s location in realtime.
• Using advanced technologies, scientists have made amazing discoveries about the duration and pattern of albatrosses’ flight. According to their findings, some albatrosses travel all the way around the world at least twice in one year!
• The globe skimmer dragonflies are known for the longest insect migration. It travels as many as 17,700 kilometres over four generations!
• The bar-tailed godwits can fly for 8 to 9 days consecutively without a break to drink or eat something!
• These wading birds (godwits) fly from the Arctic – where they breed during summer – to Australia or New Zealand (in winter) with a round-trip distance of 29,000 kilometres!
• In their lifetime, these brownish shorebirds (godwits) fly for about 460,000 kilometres, i.e. more than the distance between the moon and the earth!
• Before setting off on migration, the bar-tailed godwit eats so much that it nearly doubles its weight!
• A humpback whale is known for one of the longest migratory journeys of any mammal on the planet! It migrates about 5,000 kilometres on average.
• Did you know? A migrating Canada goose, weighing about 14 pounds, can fly about 966 kilometres without stopping!
• The red knot, a shorebird, uses all of its body fat for energy during migration. This amazing bird makes an amazing three-day nonstop flight of 3,700 km over the Brazilian rainforest!
• April Pulley Sayre (2018) in “Here Come the Humpbacks” makes an amazing revelation about the humpback whales saying that they swim in every ocean on earth.