March is a big month for animal migrations. The onset of Spring signals many animals to make moves to locations for breeding and better food. Continue reading to find out who is on the move this month!
The Ruby throated hummingbird is one of the smallest animals to make such a big trek with their journey being about 1,400 miles long. Weighing in at only three grams (the weight of a penny!) they have one of the most extreme body weight to metabolism ratios in the world. Their little hearts can beat up to 1260 beats in one minute and even at rest they have a breathing rate of around 250 breaths per minute. The small birds fly over the gulf of Mexico to central America when the Northeast becomes too cold. At the beginning of March they typically migrate back into Florida and by the end of the month can be seen coming into North Carolina. As April comes along the tiny birds continue to follow the spring weather up into the northern states.
Similar to ruby throated hummingbirds, the green darner dragonfly migrates up and down the East coast of North America. Scientists have had a hard time collecting good quality data on the insect due to their small size and the fact that they do not typically travel in a swarm like the well-known monarch butterfly. Instead, the Darner dragonfly prefers to keep a low profile when migrating. Because of this, scientists have had to adapt their methods to gather data on the dragonflies and sadly it does not involve strapping small GPS tracking systems onto their backs’. Instead, scientists look at the hydrogen isotopes in their wings and from that information, they are able to assume the general area from which a dragonfly spent it’s early larvae days in.
On the west coast at this time, Gray whales can be seen trekking back North to Alaska. The journey is risky with gray whales going up against Orcas, fishing boats and lack of food. In total, the trip is around 12,000 miles and takes place over the course of a few months. This lengthy trip is one of the longest mammal migrations. Watching the whales from shore and by boat has become a huge part of ecotourism in California.
The length of migration in caribou populations depends on the size of the herd. Larger herds tend to move farther distances and can reach up to 400 miles in search of the Arctic tundra’s coastline. This summer retreat helps the caribou nurture their young with a seabreeze that keeps insects at bay and plenty of nutrient dense food. As the winter approaches the land becomes a brutal, windy environment and the caribou, with their new calves, make the journey back to Alaska’s boreal forest. The boreal forest also known as the Taiga or snow forest is a harsh environment, but one that the caribou are well suited for. Their wide hooves make excellent snow shoes and their hollow hairs insulate them well. Their special hair also acts as a personal life vest and helps to keep them afloat when crossing the many rivers they encounter on their migration.
A very well- known migratory route is that of the Arctic Tern. This bird migrates between the Arctic and Antarctic. Going between the two poles is no easy feat and the Arctic tern has one of the longest migratory routes on the planet with its yearly tour of about 25,000 miles. These birds continue to do this for decades. The oldest Arctic Tern ever recorded was 34 years of age from the state of Maine. A picture of their annual trip can be found down below.