By Chloe Winkler and Amy Phillips
Fall affects us all in many different ways! As humans we tend to snuggle up inside with pumpkin-themed drinks and wait for cold weather, anticipating the holidays. Animals on the other hand have hard preparations for the looming winter or extension travel to warmer wintering grounds. We will touch on a few of the fascinating ways that animals prepare for winter in this changing season.
Birds
As days get shorter and temperatures start to drop many species are triggered into frantic modes. Either gathering food, finding mates, or storing up fat. Migration for birds occurs in the spring and the fall. However, fall migration is vital for many different bird species to escape extreme weather conditions and find more available food resources. When days start to shorten, and nesting locations change as trees lose their leaves birds undergo hyperphagia. This is where they begin to eat excessive amounts of food for a couple of weeks or more to store fat before migration. This supply of fat helps provide the traveling birds with necessary energy and nutrients to survive the physically demanding journey.
Some species like Blue-jays, Killdeer, and White-crowned Sparrows generally stay within North America roaming to find better weather conditions, not traveling too far. While others like Swainson’s Hawks, Turkey Vultures, and Hummingbirds travel hundreds to thousands of miles to reach their wintering grounds. Peak migration occurs from mid-August to mid-October. Although it is still largely a mystery, scientists have learned that migrating birds use various techniques along their journey to find their way. Including navigation by the stars, sensing changes in the earth’s magnetic field and even potentially smell.
Along their routes, many birds utilize stopover sites between migratory flights to rest, refuel and sometimes seek shelter before resuming their journeys. Uniquely most birds migrate at night while we are sleeping. Scientists have developed live migration maps to view summaries of radar-based measurements of nocturnal bird migration. Check out BirdCast – Bird migration forecasts in real-time if you are interested in seeing how many migrating birds are passing through your own backyard. Just one of the many struggles for migrating birds especially those traveling at night are bright lights. They can disorient the birds and cause collisions with buildings. Turn off all non-essential lights from 11pm to 6am each night during migration season.
Mammals
For ungulates like deer, elk, and pronghorn, the seasonal change means moving from the high country to lower elevations. The journey is energetically expensive, but necessary to avoid the deep snow and colder temperatures of higher elevations. Migration routes are learned and maintained year after year. While the herd may change their route in response to wildfire, mass wasting events (e.g., landslides), and other obstructions, migration routes generally stay the same for long periods. Increased development in the form of roads, houses, and fences can make migration more dangerous. As migration begins, you may notice more movement along roadways. You can help migrating ungulates by staying aware and being prepared to stop.
Compounding the energetic expense of movement in the fall is a period of breeding, known as “the rut.” This energetically expensive period is the breeding season when male ungulates compete for access to females. The male ungulates become territorial and aggressive toward each other, occasionally fighting. If a challenge goes awry, an animal can also become injured. Male ungulates often lose substantial body weight—their focus during this time is on breeding rather than eating. A bull elk can lose about 20 percent of its body weight during the rut. From this period of frenzied activity with both the migration and rut, ungulates enter winter, a time of food scarcity.
Looking forward to a brighter future
Migration is important for animals and humans. By observing birds and ungulates scientists, researchers, conservationists, and everyday people can develop a better understanding of migratory behavior. Learning how migration plays a critical role in maintaining abundant and healthy animal populations as well as how we can better conserve habitat and ecosystems for these amazing animals.